Breeding and Genetics of Prunus and Rosa Adapted to Mild Winter Humid Climates

BREEDING AND GENETICS OF PRUNUS AND ROSA ADAPTED TO MILD WINTER HUMID CLIMATES

Sponsoring Institution

National Institute of Food and Agriculture

Project Status

COMPLETE

Funding Source

HATCH

Reporting Frequency

Annual

Accession No.

0092534

Grant No.

(N/A)

Cumulative Award Amt.

(N/A)

Proposal No.

(N/A)

Multistate No.

(N/A)

Project Start Date

Jul 22, 2008

Project End Date

Jul 21, 2014

Grant Year

(N/A)

Program Code

[(N/A)]- (N/A)

Recipient Organization
TEXAS A&M UNIVERSITY
750 AGRONOMY RD STE 2701
COLLEGE STATION,TX 77843-0001

Performing Department
Horticultural Science

Non Technical Summary
Fruit production in the southern half of the USA is limited by a lack of well-adapted varieties. The development of high-quality, early-ripening varieties for southern climates will allow growers to tap the lucrative market window beginning in early April, after imported South American fruit is no longer available, and ending before the major fruit growing zones of California and Georgia begin to saturate the market in late May. This project combines a traditional breeding program with research into better methodology to produce the appropriate progeny and better information about the diversity of germplasm to enhance our ability to use this germplasm. With a series of peach and nectarine cultivars that ripen consecutively to allow a continuous supply of fruit to market, production in the southern half of the USA could increase from the present 5,000 acres to 50,000 acres or more. Roses in southern hot humid climates suffer from a lack of heat tolerance and resistance to black spot. This project combines a traditional breeding approach with the development of further information on the genetics and markers associated with important traits as well as the genetic diversity of the breeding germplasm to improve the breeding approach. The project will result in new rose varieties well adapted to the hot humid climate that will not require pesticide sprays to maintain them in a healthy state.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
202	1114	1081	10%
202	1116	1081	10%
202	1114	1080	10%
203	1111	1081	10%
203	1113	1081	20%
203	1114	1081	20%
203	1116	1081	10%
212	2110	1081	10%

Knowledge Area
212 - Pathogens and Nematodes Affecting Plants; 203 - Plant Biological Efficiency and Abiotic Stresses Affecting Plants; 202 - Plant Genetic Resources;

Subject Of Investigation
1111 - Apricot; 1114 - Peach; 2110 - Ornamental trees and shrubs; 1113 - Nectarine; 1116 - Plum;

Field Of Science
1081 - Breeding; 1080 - Genetics;

Keywords

Goals / Objectives
Prunus: develop low chill and early ripening peach varieties with enhanced organoleptic, handling, and health promoting properties (goal: 5 variety releases), improve the ability to grow immature peach embryos from early ripening peaches (goal: improve survival rate by 10%), survey the health promoting properties of stone fruit (goal: identify varieties with health promoting qualities and the phytochemicals responsible for these qualities), and understand the diversity among peach germplasm from South America, North America, and China (goal: characterize 150 selected peach genotypes for 20 SSRs and do analysis to better design germplasm collection and introgression strategies). Rosa: develop landscape rose varieties that are resistant to black spot and powdery mildew, heat tolerant, and with a compact plant form, high flower production, no prickles, and a range of flowers forms and colors (goal: release 5 new rose varieties), and develop basic information on the genetics of the rose (goals: develop genetic-physical map, map black spot resistance and recurrent bloom traits, characterize 200 roses for 30 SSR markers to assess the genetic diversity of the chinensis group and the Moore rose breeding collection).

Project Methods
Both crops will be developed using traditional recurrent selection approach with the introgression of exotic germplasm to incorporate specific traits related to quality, adaptability, and disease resistance as needed. In the rose project work is done at both the diploid and tetraploid levels. Microsatellites are used in the mapping as well as the diversity studies. The rose mapping population is being evaluated in the field for a range of horticultural and black spot resistance and in the laboratory for 400 SSR markers. This data will be analyzed to develop a map using MapMaker software and markers identified that are linked to important traits. Diversity data will be analyzed with NTSYS software. Embryo rescue experiments will test various variations on the standard method on multiple genotypes and years to determine which variations consistently improve survival. A set of commercial stone fruit will be assayed for their effect on LDL oxidation, platelet aggregation, and their abilities to inhibit the proliferation of various cancer cell lines. Once these are characterized a few selected varieties will be further studied to identify the phytochemicals and mechanisms involved in the characterized bioactivity. The ultimate result of this project will be the release of peach and rose varieties adapted to the hot, humid climate of the southern USA to enhance both commercial and backyard production of peaches and the landscape use of roses.

Progress 07/22/08 to 07/21/14

Outputs
Target Audience: Releases and information developed by the applied stone fruit and rose breeding programs are developments for the farmers, nursery industry, and gardeners in Texas and in areas of similar environments. This information is distributed via talks at various garden and hobby fruit groups, a web page, a Facebook page, an email Rose Research Update Newsletter, Agrilife Extension, TAMU Agricultural Communications as well as through commercial partners. The scientific information developed in the areas of stone fruit and rose genetics and the health benefits of stone fruit is aimed at the scientific community. It is distributed via referred scientific journals, national/international scientific meetings, and articles in the popular press. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Two Brazilian visiting scientist and six graduate students (Jake Ueckert, Qianni Dong, Muqing Yan, Shuyin Liang, Xuan Wu, Ellen Roundey) have worked and been trained in the scientific approach to applied plant breeding on this project. How have the results been disseminated to communities of interest? Releases and information developed by the applied stone fruit and rose breeding programs are developments for the farmers, nursery industry, and gardeners in Texas and in areas of similar environments. This information is distributed via talks at various garden and hobby fruit groups, web pages, a Facebook page, Rose Research Update email newsletter, Agrilife Extension, TAMU Agricultural Communications as well as through commercial partners. The scientific information developed in the areas of stone fruit and rose genetics and the health benefits of stone fruit is aimed at the scientific community. It is distributed via referred scientific journals, national/international scientific meetings, and articles in the popular press. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Ten new medium chill and three new low chill selections were made and propagated for additional testing. Fifteen new peach and 7 new nectarine cultivars were released for both the commercial and backyard markets. This includes the peaches - TexFirst, Flame Zest, King Zest, the Royal Zest series (4 cv), Golden Zest, the White Delight series (4 cv), White Zest, and the Flat Delight Series (2 cv) and the nectarines - Smooth Texan (3 cv), Smooth Delight (2 cv) and Smooth Zest (2 cv) nectarine cultivars. These releases are a major advance in the classes of fruit available for this zone as it improves on the traditional yellow-flesh peaches (Royal Zest series) but also introduces adapted varieties of more classes such as nectarines, white fleshed peaches and donut peaches. The Rosbreed project has developed SNP markers for flesh texture, flesh color, fruit type, red blush, acidity, ripening time and bacterial leaf spot which were used to survey the breeding germplasm. This information will be used in designing crosses for 2014. An analysis of 8 peach progenies planted in Texas and California indicated that there was a significant genotype x environment interaction for fruit red blush, fruit size, fruit shape, and fruit ground color, red in the flesh, fruit firmness, and soluble solids indicating that regional selection is essential in cultivar development. The rose crosses this year concentrated on the introgression of the Moore germplasm into the highly black spot resistant Basye and TAMU derived roses as well as the creation of diploid rose populations to study the inheritance of black resistance, heat tolerance, flower yield, and other important commercial traits. Preliminary analysis indicates that partial black spot resistance, components of plant architecture and flower size are moderately heritable. The triploid rose 'Home Run'produces approximately equal numbers of haploid and diploid pollen in crosses with several diploid and tetraploid female parents.

Publications

Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Kongsri, S., U. Boonprakob, and D. H. Byrne. 2014. Assessment of morphological and physiological responses of peach rootstocks under drought and aluminum stress. Acta Hort. 1059:229-236.
Type: Theses/Dissertations Status: Published Year Published: 2014 Citation: Ueckert, J. 2014. Understanding and manipulating polyploidy in garden roses. M.S. thesis. Texas A&M University, May, 2014.
Type: Theses/Dissertations Status: Published Year Published: 2014 Citation: Dong, Q. 2014. Characterization of black spot resistance in partial diallel cross populations of Rosa spp. Ph.D. Texas A&M University. December, 2014.
Type: Journal Articles Status: Published Year Published: 2014 Citation: Bhimanagouda S. Patil, Kevin Crosby, David Byrne and Kendal Hirschi. 2014. The Intersection of Plant Breeding, Human Health, and Nutritional Security: Lessons Learned and Future Perspectives. HortScience 49(2):116-127.
Type: Journal Articles Status: Published Year Published: 2014 Citation: Greyvenstein, O., H. B. Pemberton, T. Starman, G. Niu, and D.H. Byrne. 2014. Effect of Two Week High Temperature Treatment on Flower Quality and Abscission of Rosa L. 'Belinda's Dream' and 'RADrazz' Under Controlled Growing Environments. HortScience, 49 (6): 701-705.
Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Byrne, D. H. 2014. Progress and potential of low chill peach breeding. Acta Hort. 1059:59-66
Type: Journal Articles Status: Published Year Published: 2014 Citation: Wang, Q., T. Cheng, X. Yu, J. A. Teixeira, and D.H. Byrne. 2014. Physiological and biochemical responses of six herbaceous peony cultivars to cold stress. South African J. Botany 94:140-148.
Type: Journal Articles Status: Published Year Published: 2014 Citation: Vizzotto, M., W. Porter, D. Byrne, and L. Cisneros-Zevallos. 2014. Polyphenols of selected peach and plum genotypes reduce cell viability and inhibit proliferation of breast cancer cells while not affecting normal cells. Food Chem. 164:363-370.
Type: Journal Articles Status: Published Year Published: 2014 Citation: Byrne, D. H. and N. Anderson. 2014. Smooth Texan nectarines, Three medium chill, early season yellow cultivars. HortScience 49 (8):1095-1096.
Type: Journal Articles Status: Published Year Published: 2014 Citation: Byrne, D. H. and N. Anderson. 2014. Smooth Delight One and Two, medium chill subacid nectarines. HortScience, 49(12):1593-1594.
Type: Journal Articles Status: Published Year Published: 2014 Citation: Noratto, G. D., J. F. Garcia-Mazcorro, M. Markel, H. S. Martino, Y. Minamoto, J. M. Steiner, D. Byrne, J.S. Suchodolski, and S.U. Mertens-Talcott. 2014. Peach (Prunus persica) and plum (Prunus salicina) extracts alter fecal microbial ecology in obese Zucker rats. PLOSOne 9(7): e101723. doi:10.1371/ correction journal.pone.01017239(8):e106128.
Type: Journal Articles Status: Published Year Published: 2014 Citation: Noratto, G. W. Porter, D. Byrne and L. Cisneros-Zevallos. 2014. Polyphenolics from peach (Prunus persica var. Rich Lady) inhibit tumor growth and metastasis of MDA-MB-435 breast cancer cells in vivo. J. Nutr. Biochem. 25:796-800.

Progress 01/01/13 to 09/30/13

Outputs
Target Audience: Releases and information developed by the applied stone fruit and rose breeding programs are developments for the farmers, nursery industry, and gardeners in Texas and in areas of similar environments. This information is distributed via talks at various garden and hobby fruit groups, Agrilife Extension, TAMU Agricultural Communications as well as through commercial partners. The scientific information developed in the areas of stone fruit and rose genetics and the health benefits of stone fruit is aimed at the scientific community. It is distributed via referred scientific journals, national/international scientific meetings, and articles in the popular press. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? One Chinese, one Pakistani, and 2 Brazilian visiting scientist and eight graduate students ( Amy Tsai, Jake Ueckert, Tim Hartmann, Qianni Dong, Ockert Greyvenstein, Muqing Yan, Shuyin Liang, Xuan Wu) have worked and been trained in the scientific approach to applied plant breeding on this project. How have the results been disseminated to communities of interest? Releases and information developed by the applied stone fruit and rose breeding programs are developments for the farmers, nursery industry, and gardeners in Texas and in areas of similar environments. This information is distributed via talks at various garden and hobby fruit groups, Agrilife Extension, TAMU Agricultural Communications as well as through commercial partners. The scientific information developed in the areas of stone fruit and rose genetics and the health benefits of stone fruit is aimed at the scientific community. It is distributed via referred scientific journals, national/international scientific meetings, and articles in the popular press. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Thirty-six new low and medium chill peach selections were made and additional ones were planted into 2nd and third test evaluation trials. Twelve new peach and 7 new nectarine cultivars were released this year for both the commercial and backyard markets. This includes the peaches - Royal Zest series (4 cv), Golden Zest, the White Delight series (4 cv), White Zest, and the Flat Delight Series (2 cv) and the nectarines - Smooth Texan (3 cv), Smooth Delight (2 cv) and Smooth Zest (2 cv) nectarine cultivars. These releases are a major advance in the classes of fruit available for this zone as it improves on the traditional yellow-flesh peaches (Royal Zest series) but also introduces adapted varieties of more classes such as nectarines, white fleshed peaches and donut peaches. The Rosbreed project has developed SNP markers for flesh texture, flesh color, fruit type, red blush, acidity, ripening time and bacterial leaf spot which were used to survey the breeding germplasm. This information will be used in designing crosses for 2014. An analysis of 8 peach progenies planted in Texas and California indicated that there was a significant genotype x environment interaction for fruit red blush, fruit size, fruit shape, and fruit ground color, red in the flesh, fruit firmness, and soluble solids indicating that regional selection is essential in cultivar development. The rose crosses this year concentrated on the introgression of the Moore germplasm into the highly black spot resistant Basye and TAMU derived roses as well as the creation of diploid rose populations to study the inheritance of black resistance, heat tolerance, flower yield, and other important commercial traits. The diploid rose map was aligned with the tetraploid rose map indicating substantial synteny. The tetraploid progeny displays both disomic and tetrasomic inheritance. Cell membrane stability after a short heat shock was not well correlated with field performance of roses although the degree of flower abortion and leaf damage was well correlated to field hot season performance. The development of medium and low chill Prunus varieties will open up the southern regions of the country for peach production advancing the commercial harvest by 2-3 weeks. Current releases are a major advance in the cultivars available in this zone as it expands the traditional yellow peach available but also expands the products available to nectarines, low and high acid white peaches and sweet donut peaches. Disease resistant rose varieties would expand the market for roses as a landscape plant and reduce the amount of pest and disease control chemicals needed to maintain the plants’ health.

Publications

Type: Journal Articles Status: Published Year Published: 2013 Citation: Niu, G., T. Starman, and D. H. Byrne. 2013. Responses of growth and mineral nutrition of garden roses to saline water irrigation. HortScience 48:756-761.
Type: Journal Articles Status: Published Year Published: 2013 Citation: Byrne, D. H. and N. Anderson. 2013. White Delight peach series: A low acid white-flesh peach series for the medium chill zone. HortScience 48:1056-1058.
Type: Journal Articles Status: Awaiting Publication Year Published: 2014 Citation: Greyvenstein, O., H. B. Pemberton, T. Starman, G. Niu, and D.H. Byrne. Effect of Two Week High Temperature Treatment on Flower Quality and Abscission of Rosa L. 'Belinda's Dream' and 'RADrazz' Under Controlled Growing Environments. HortScience, in press.
Type: Journal Articles Status: Published Year Published: 2013 Citation: Farooq, A., M. Kiani, M. A. Khan, A. Riaz, A. A. Khan, N. Anderson, and D. H. Byrne. 2013. Microsatellite analysis of Rosa damascena from Pakistan and Iran. Hort. Environ. Biotechnol. 54:141-147.
Type: Journal Articles Status: Awaiting Publication Year Published: 2014 Citation: Bhimanagouda S. Patil, Kevin Crosby, David Byrne and Kendal Hirschi. 2014. The Intersection of Plant Breeding, Human Health, and Nutritional Security: Lessons Learned and Future Perspectives. HortScience, in press

Progress 01/01/12 to 12/31/12

Outputs
OUTPUTS: Fifty-six new low and medium chill peach selections were made and additional ones were planted into 2nd and third test evaluation trials. The TexFirst peach and the White Delight subacid white fleshed peach series were released. The White Delight series is the first series of subacid white fleshed peaches adapted to the medium chill zone. Collaborative work with Drs. Talcott and Turner showed that peach and plum juice consumption protected obese Zucker rats against obesity-induced metabolic disorders. Plum juice due to its three fold higher phenolic concentration also prevented weight gain. The rose crosses this year concentrated on the introgression of the Moore germplasm into the highly black spot resistant Basye and TAMU derived roses as well as the creation of diploid rose populations to study the inheritance of black resistance, heat tolerance, flower yield, and other important commercial traits. These progenies will also be genotyped and searched for marker-traits associations that may be useful in rapid introgression from wild species and parental selection. The TAMU-Moore rose germplasm collection was found to have tetraploid (78%), triploid (7%), and diploid (14%) accessions. Two years of heat tolerance evaluations in the field as measured by flower production in August indicated that 6% of the TAMU-Moore rose collection has high heat tolerance. This tolerance appears to be well correlated to lab measurements of cell membrane stability. Laboratory detached leaf measurements appear to be well correlated to field assessments of black spot resistance in roses. PARTICIPANTS: One Chinese visiting scientist worked with the program on peach breeding and genetics. In addition, one employee (Natalie Anderson) and five graduate students ( Amy Tsai, Jake Ueckert, Tim Hartmann, Qianni Dong, Ockert Greyvenstein) have worked on this project. I have also collaborated with both commercial partners (Burchell Nurseries, Modern Agriculture Company-Pico, La Tiesa, Colors, Grupo Alta, Seville Nurseries, Antique Rose Emporium, Greenheart Nurseries, Kawamoto Nursery, Capstone Plants, Greenleaf Nursery) and public institutions (EMBRAPA, Kasetsart University, USDA, Clemson University, Zhengzhou Fruit Research Institute) in various aspects of my projects. TARGET AUDIENCES: Releases and information developed by the applied stone fruit and rose breeding programs are developments for the farmers, nursery industry, and gardeners in Texas and in areas of similar environments. This information is distributed via talks at various garden and hobby fruit groups, Agrilife Extension, TAMU Agricultural Communications as well as through commercial partners. The scientific information developed in the areas of stone fruit and rose genetics and the health benefits of stone fruit is aimed at the scientific community. It is distributed via referred scientific journals, national/international scientific meetings, and occasional articles in the popular press. PROJECT MODIFICATIONS: None

Impacts
The development of medium and low chill Prunus varieties will open up the southern regions of the country for peach production advancing the commercial harvest by 2-3 weeks. Varieties of peach, nectarine and plums have been shown to have health benefits that include high antioxidant activity, good antiproliferative activity against breast, colon, and prostate cancer cells, excellent LDL oxidant inhibition, anti inflammatory activity and protection against obesity-induced metabolic disorders. The level of the health benefit varied with the specific variety assayed. Disease resistant rose varieties would expand the market for roses as a landscape plant and reduce the amount of pest and disease control chemicals needed to maintain the plants' health.

Publications

Byrne, D. H., N. Anderson, Q. Dong, J. Ueckert, and O. Greyvenstein. 2012. Field evaluation of heat tolerance in rose. (abstract). Annual American Society of Horticultural Sciences meeting. August, 2012. Miami, Florida.
Carver, S. M. Arnold, D. Byrne, A. Armitage, and A. King. 2012. Three plant growth regulators modify growth and flowering responses of Rorrichia frutescens (L.) DC. Produced in containers (poster # 141). (abstract). Annual American Society of Horticultural Sciences meeting. August, 2012. Miami, Florida.
Greyvenstein, O., T. W. Starman, H. B. Pemberton, G. Niu, and D. H. Byrne. 2012. Cell membrane stability provided better resolution for screening heat tolerance in garden roses than did chlorophyll fluorescence (poster #398). (abstract). Annual American Society of Horticultural Sciences meeting. August, 2012. Miami, Florida.
Frett, T. J., K. Gasic, J. R. Clark, D. H. Byrne, T. Gradziel and C. Crisosto. 2012. Standardized phenotyping for fruit quality in peach [Prunus persica (L.) Batsch]. J. Amer. Pomol. Soc. 66 (4): 214-219
Byrne, D. H. and N. Anderson. 2012. `TexFirst', An early ripening low chill peach for the subtropics. HortScience 47:1803-1804
Ueckert, J., D. Stelley, K. Crosby, and D. H. Byrne. 2012. The ultilization of the polyploidy nature of roses (poster #396). (abstract). Annual American Society of Horticultural Sciences meeting. August, 2012. Miami, Florida.
Dong, Q., D. H. Byrne, and X. Wang. 2012. Characterization of resistance genes of Rosa spp. To black spot by molecular markers (poster #399). (abstract). Annual American Society of Horticultural Sciences meeting. August, 2012. Miami, Florida.
Byrne, D. H. 2012. White Delight peach series: medium chill, low-acid, white-fleshed peach cultivars (poster #193). (abstract). Annual American Society of Horticultural Sciences meeting. August, 2012. Miami, Florida.
Patil, B. S., K. Crosby, D. H. Byrne, and K. Hirschi. 2012. The intersection of plant breeding, human health, and nutritional security: Lessons learned and future perspectives. (abstract). Annual American Society of Horticultural Sciences meeting. August, 2012. Miami, Florida.
Badenes, M. and D. H. Byrne (eds.) 2012. Handbook of plant breeding: Fruit breeding. Springer, New York. 875 p., 83 illus., Hardcover. ISBN: 978-1-4419-0762-2
Gasic, K., D. H. Byrne, et al., 2012. Loci important for peach and cherry fruit size and quality: What is known about their functional alleles (abstract). Annual American Society of Horticultural Sciences meeting. August, 2012. Miami, Florida.
Byrne, D. H. 2012. Trends in fruit breeding, p 3-36. Handbook of plant breeding: Fruit breeding. In: M. Badenes and D. H. Byrne (eds.). Springer, New York.
Byrne, D. H., M. C. Raseira., S. Perez, D. Bassi, M. C. Piagnani, M. C. Moreno, K., Gasic and G. Reighard. 2012. Peach breeding, p 505-570. Handbook of plant breeding: Fruit breeding. In: M. Badenes and D. H. Byrne (eds.). Springer, New York.
Wargovich, M., J. Morris, V. Moseley, R. Weber, and D.H. Byrne. 2012. Developing fruit cultivars with enhanced health properties, p 37-68. Handbook of plant breeding: Fruit breeding. In: M. Badenes and D. H. Byrne (eds.). Springer, New York.

Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: Forty-two new low and medium chill peach selections were made and additional ones were planted into 2nd and third test evaluation trials. The low chill peach, TexFirst was released and series of nectarines, low acid white peaches, and yellow peaches were selected for release in this coming year. The populations of high sugar progenies being used in the ROSBreed project was planted in both California and Texas. Research into the health benefits of stone fruit indicated that the antioxidant polyphenolics found in plum extracts help lessen weight gain in obese rats. The Ralph Moore Rose collection has been evaluated in California and Texas. Of the 600 roses evaluated, there was about 1% that were very heat tolerant as determined by their growth and flowering in field plots during August (mean temperature 90 F). Growth chamber studies showed that a heat shock at the time when the flower bud is visible has as much effect as a constant heat treatment. In addition, there was a good correspondence between the heat tolerance as rated in the field and that as measured by cell membrane stability. We developed a tetraploid rose map in collaboration with partners in Israel. PARTICIPANTS: One Ph.D student from China(Beijing Institute of Landscape Architecture) was trained in Rose Breeding and Genetics and another from Thailand (Kasetsart University) worked on abiotic stress resistance in Prunus rootocks. In addition, two employees (Natalie Anderson and Manuel Michel) and five graduate students (Amy Tsai, Tim Hartmann, Ockert Greyvenstein, Jacob Ueckert, Qianni Dong) have worked on this project. I have also collaborated with both commercial partners (Burchell Nurseries, Modern Agriculture Company-Pico, La Tiesa, Colors, Seville Farms, Rhew Farm, Cooper Farms, Ham Orchard, Grupo Alta) and public institutions (EMBRAPA, Kasetsart University, USDA, Zhengzhou Fruit Research Institute, Hebrew University) in various aspects of my projects. TARGET AUDIENCES: Releases and information developed by the applied stone fruit and rose breeding programs are developments for the farmers, nursery industry, and gardeners in Texas and in areas of similar environments. This information is distributed via talks at various garden and hobby fruit groups, Agrilife Extension, TAMU Agricultural Communications as well as through commercial partners. The scientific information developed in the areas of stone fruit and rose genetics and the health benefits of stone fruit is aimed at the scientific community. It is distributed via referred scientific journals, national/international scientific meetings, and occasional press releases and articles in the popular press. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The development of medium and low chill Prunus varieties will open up the southern regions of the country for peach production advancing the commercial harvest by 2-3 weeks. Varieties of peach, nectarine and plums have been shown to have health benefits that include high antioxidant activity, good antiproliferative activity against breast, colon, and prostate cancer cells, excellent LDL oxidant inhibition, and anti inflammatory activity. The level of the health benefit varied with the specific variety assayed. Disease resistant rose varieties would expand the market for roses as a landscape plant and reduce the amount of pest and disease control chemicals needed to maintain the plants' health.

Publications

Puerta-Gomez, A. F., D. H. Byrne, and L. Cisneros-Zevallos. 2011. Postharvest studies beyond fresh market eating quality: Phytochemical antioxidant changes in peach and plum fruit during ripening and advanced senescence. Postharvest Biol. Technol. 60: 220-224.
Spiller, M., M. Linde, L. Hibrand-Saint Oyant, C. Tsai, D. H. Byrne, M. J. Smulders, F. Foucher, and T. Debener. 2011. Towards a unified genetic map for diploid roses. Theoretical and Applied Genetics 122(3):489-500.
Gar O, D. J. Sargent, C-J Tsai, T. Pleban, G. Shalev, D. H. Byrne and D. Zamir. 2011. An Autotetraploid Linkage Map of Rose (Rosa hybrida) Validated Using the Strawberry (Fragaria vesca) Genome Sequence. PLoS ONE 6(5): e20463. Doi:10.1371 /journal.pone.0020463 .

Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: Sixty-five new low and medium chill peach selections were made and additional ones were planted into 2nd and third test evaluation trials. An analysis of the SSR diversity of low chill peach germplasm indicates that Brazilian germplasm is distinct from peaches from the USA, China or Thailand and that the local low chill peach cultivars from Asia are distinct from all other peach cultivars studied. Research into the health benefits of stone fruit indicated that the polyphenolics found in plum extracts suppress inflammation and oxidative stress in human umbilical vein endothelial cells. In a rat colitis model system, chlorogenic acid, the major phenolic compound found in peach and plums reduced inflammation. The Ralph Moore Rose collection was evaluated Texas. With colleagues in Europe, the first rose consensus map was constructed. PARTICIPANTS: One Pakistani Ph.D student from the Agriculture University of Faisalabad was trained in the area of molecular markers and pedigree analysis and a Ph.D student from Kasesart University in Bangkok, Thailand is researching drought and aluminum tolerance Prunus rootstocks . In addition, two employees (Natalie Anderson and Manuel Michel) and five graduate students (Matt Orwat, Amy Tsai, Jake Ueckert, Tim Hartmann, Ockert Greyvenstein) have worked on this project. I have also collaborated with both commercial partners (Burchell Nurseries, Modern Agriculture Company-Pico, La Tiesa, Colors, California Tree Fruit Agreement, Grupo Alto, Seville Nurseries, Antique Rose Emporium, Greenheart Nurseries) and public institutions (EMBRAPA, Kasetsart University, USDA, INRA, Yunnan Academy of Agricultural Sciences, Zhengzhou Fruit Research Institute) in various aspects of my projects. TARGET AUDIENCES: Releases and information developed by the applied stone fruit and rose breeding programs are developments for the farmers, nursery industry, and gardeners in Texas and in areas of similar environments. This information is distributed via talks at various garden and hobby fruit groups, Agrilife Extension, TAMU Agricultural Communications as well as through commercial partners. The scientific information developed in the areas of stone fruit and rose genetics and the health benefits of stone fruit is aimed at the scientific community. It is distributed via referred scientific journals, national/international scientific meetings, and occasional articles in the popular press. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The development of medium and low chill Prunus varieties will open up the southern regions of the country for peach production advancing the commercial harvest by 2-3 weeks. Varieties of peach, nectarine and plums have been shown to have health benefits that include high antioxidant activity, good antiproliferative activity against breast, colon, and prostate cancer cells, excellent LDL oxidant inhibition, and anti inflammatory activity. The level of the health benefit varied with the specific variety assayed. Disease resistant rose varieties would expand the market for roses as a landscape plant and reduce the amount of pest and disease control chemicals needed to maintain the plants' health.

Publications

Spiller, M., M. Linde, L. Hibrand-Saint Oyant, C. Tsai, D. H. Byrne, M. J. Smulders, F. Foucher, and T. Debener. 2010. Towards a unified genetic map for diploid roses. Theoretical and Applied Genetics DOI 10.1007/s00122-010-1463-x
Byrne, D. H., N. Anderson, M. Orwat, and V. Soules. 2010. Field assessment of black spot resistance in roses in a hot humid climate. Acta Hort.870:115-120
Kiani, M., Z. Zamani, A. Khalighi, R. Fatahi, and D. H. Byrne. 2010. A unique germplasm of Damask roses in Iran. Acta Hort. 870:131-136.
Byrne, D. H. 2010. Environmental challenges of breeding peaches for low chill regions. Acta Hort. 872:129-138.

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: Nineteen new low and medium chill peach selections were made and additional ones were planted into 2nd and third test evaluation trials. A low chill peach and a series of low acid medium chill peaches were selected for release in this coming year. The populations of high sugar progenies being used in the ROSBreed project are being propagated and planted in both California and Texas. Preliminary analysis of low chill peach germplasm indicates that Brazilian germplasm is distinct from peaches from the USA, China or Thailand and that the local low chill peach cultivars are distinct from all other peach cultivars studied. Research into the health benefits of stone fruit indicated that the antioxidant polyphenolics found in plum extracts help control inflammation and inhibit oxidative stress in human umbilical vein endothelial cells. The Ralph Moore Rose collection was evaluated in California and will be evaluated in Texas this coming year. An examination of the microsatellite diversity of cultivated China Roses and related groups indicates that this group is closely related and highly heterozygous. In addition, it appears that the China Roses were maternally derived from R. chinensis var. spontanea. Maps containing microsatellite markers were developed and are currently being refined and incorporated into a consensus rose map with colleagues in Europe. Releases and information developed by the applied stone fruit and rose breeding programs are developments for the farmers, nursery industry, and gardeners in Texas and in areas of similar environments. This information is distributed via talks at various garden and hobby fruit groups, Agrilife Extension, TAMU Agricultural Communications as well as through commercial partners. The scientific information developed in the areas of stone fruit and rose genetics and the health benefits of stone fruit is aimed at the scientific community. It is distributed via referred scientific journals, national/international scientific meetings, and occasional articles in the popular press. PARTICIPANTS: One Pakistani Ph.D student from the Agriculture Universityof Faisalabad was trained in the area of molecular markers and pedigree analysis. In addition, two employees (Natalie Anderson and Manuel Michel) and four graduate students (Matt Orwat, Amy Tsai, Tim Hartmann, Ockert Greyvenstein) have worked on this project. I have also collaborated with both commercial partners (Burchell Nurseries, Modern Agriculture Company-Pico, La Tiesa, Colors, California Tree Fruit Agreement, Greenheart Nurseries) and public institutions (EMBRAPA, Kasetsart University, USDA, INRA, Yunnan Academy of Agricultural Sciences, Zhengzhou Fruit Research Institute, Hebrew University) in various aspects of my projects. TARGET AUDIENCES: Releases and information developed by the applied stone fruit and rose breeding programs are developments for the farmers, nursery industry, and gardeners in Texas and in areas of similar environments. This information is distributed via talks at various garden and hobby fruit groups, Agrilife Extension, TAMU Agricultural Communications as well as through commercial partners. The scientific information developed in the areas of stone fruit and rose genetics and the health benefits of stone fruit is aimed at the scientific community. It is distributed via referred scientific journals, national/international scientific meetings, and occasional articles in the popular press. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The development of medium and low chill Prunus varieties will open up the southern regions of the country for peach production advancing the commercial harvest by 2-3 weeks. Varieties of peach, nectarine and plums have been shown to have health benefits that include high antioxidant activity, good antiproliferative activity against breast, colon, and prostate cancer cells, excellent LDL oxidant inhibition, and anti inflammatory activity. The level of the health benefit varied with the specific variety assayed. Disease resistant rose varieties would expand the market for roses as a landscape plant and reduce the amount of pest and disease control chemicals needed to maintain the plants' health.

Publications

Byrne, D. H. 2009. Rose structural genetics. In: Gardiner and Folta (editors). Plant Genetics and Genomics. Volume 6. Genetics and Genomics of Rosaceae. Springer.
Kiani, M., Z. Zamani, A. Khalighi, and D. H. Byrne. 2009. Microsatellite analysis of Iranian damask rose (Rosa damascena Mill.) germplasm. Plant Breeding 128:1-7.
Noratto, G, W. Porter, D. H. Byrne, and L. Cisneros-Zevallos. 2009. Identifying peach and plum polyphenols with chemopreventive potential against estrogen-independent breast cancer cells. J. Agric. Food Chem 57:5219-5226.

Progress 01/01/08 to 12/31/08

Outputs
OUTPUTS: Five new low chill and five new medium chill peach selections were made and additional ones were planted into 2nd and third test evaluation trials. Four low chill peaches were released for use in Thailand and two other peaches were selected for release in this coming year. Multiple populations of high sugar progenies in the peach breeding program have been created in an effort to increase the organoleptic properties of these low and medium chill stone fruit. The mechanisms behind the antiproliferative activity of stone fruit extracts on breast cancer cell lines were characterized and included various apoptotic pathways. The antiproliferative activity with colon and prostate cancer cells and the LDL oxidition inhibition of stone fruit extracts were shown to vary with the variety assayed and these bioactivities were not correlated to the antioxidant activity of the variety. Thirty new rose selections that were either new diploid disease resistant roses or crosses between cultivated roses and Basye rose breeding germplasm were propagated for further evaluation and 2 advanced selections were chosen for release. The Ralph Moore rose germplasm collection, consisting of about 300 varieties and 300 unreleased selections and breeding materials, was donated to the Rose Breeding and Genetics Program and is being planted for evaluation for adaptation in a hot humid climate. An inbreeding analysis of the Moore breeding germplasm indicated there are 9 major groups of germplasm. PARTICIPANTS: One Chinese Professor from the Beijing Forestry University was trained in the area of molecular markers and pedigree analysis. In addition, two employees (Natalie Anderson and Blake Witt) and four graduate students (Matt Orwat, Amy Tsai, Naoko Nomura, Valerie Eitriem) have worked on this project. I have also collaborated with both commercial partners (Burchell Nurseries, Modern Agriculture Company-Pico, La Tiesa, Colors, California Tree Fruit Agreement, Greenheart Nurseries) and public institutions (EMBRAPA, Kasetsart University, USDA, Rutgers University, INRA, Yunnan Academy of Agricultural Sciences, Zhengzhou Fruit Research Institute, Hebrew University) in various aspects of my projects. TARGET AUDIENCES: Releases and information developed by the applied stone fruit and rose breeding programs are developments for the farmers, nursery industry, and gardeners in Texas and in areas of similar environments. This information is distributed via talks at various garden and hobby fruit groups, Agrilife Extension, TAMU Agricultural Communications as well as through commercial partners. The scientific information developed in the areas of stone fruit and rose genetics and the health benefits of stone fruit is aimed at the scientific community. It is distributed via referred scientific journals, national/international scientific meetings, and occasional articles in the popular press. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The development of medium and low chill Prunus varieties will open up the southern regions of the country for peach production advancing the commercial harvest by 2-3 weeks. Varieties of peach, nectarine and plums have been shown to have health benefits that include high antioxidant activity, good antiproliferative activity against breast, colon, and prostate cancer cells and excellent LDL oxidant inhibition. The level of the health benefit varied with the specific variety assayed. Disease resistant rose varieties would expand the market for roses as a landscape plant and reduce the amount of pest and disease control chemicals needed to maintain the plants' health.

Publications

Byrne, D. H. and U. Boonprakob. 2008. Thai Tiger low chill peach series. HortScience 43:2226-2227.
Kiani, M., Z. Zamani, A. Khalighi, R. Fatahi, and D. H. Byrne. 2008. Wide Genetic Diversity of Rosa damascena Mill. Germplasm in Iran as Revealed by RAPD Analysis. Scientia Hort. 115:386-392.
Promchot, S. U. Boonprakob, and D. H. Byrne. 2008. Genotype and environmental interaction of low-chill peaches and nectarines in subtropical highlands of Thailand. Thai J. Agric. Sci. 41(1-2):53-61.
Lea, M., C. Ibeh, C. desBordes, M. Vizzotto, L. Cisneros-Zevallos, D. H. Byrne, W. R. Okie, and M.P. Moyer. 2008. Inhibition of Growth and Induction of Differentiation of Colon Cancer Cells by Peach and Plum Phenolic Compounds. Anticancer Research 2008 Jul-Aug; Vol. 28 (4B), pp. 2067-76.

Progress 01/01/07 to 12/31/07

Outputs
OUTPUTS: Fourteen low chill early ripening (April to mid May) peach and nectarine selections were identified. Of these 4 were nectarines and 3 were white fleshed peaches. At College Station 2 nectarine and 19 peach selections were made. Of these, there are 8 white fleshed and 9 low acid selections. A low chill early ripening peach, a medium chill low acid white nectarine and a low acid white peach are slated for release this year. Peach and plum phenolic extracts inhibited the proliferation of the estrogen-independent MDA-MB-435 breast cancer cell line more than the non cancerous breast cell line (MCF-10A) or the estrogen-dependent breast cancer cell line (MCF-7). The effectiveness on the extract to inhibit MDA-MB-435 breast cancer proliferation varied with the variety. This effect was clear in the fraction 1 which contained mainly the phenolic acids chlorogenic and neo chlorogenic acids. Further studies on the mechanism of this antiproliferative response employing the MEK-MAK inhibitor revealed that prolonged ERK activation by F1 mediated the apoptosis machinery and that MEK-MAK blockage modified the cytotoxicity exerted by F1 through mitochondria permeabilization, indicating that prolonged MEK-MAK activation may be linked to cell death. Screening of peach, nectarine, and plum germplasm has revealed a range of capacity to inhibit LDL oxidation from very low to excellent. One hundred and four SSR primer pairs were identified to be polymorphic in our diploid OBxWOB26 rose mapping population. The population has been characterized for 19 of these SSRs. Rose oil germplasm, Rosa damascena, from Iran was shown to be highly diverse as compared to the germplasm studied in Turkey and Bulgaria. Breeding efforts have developed highly floriferous, compact, and black spot resistant diploid selections derived from breeding with R. wichurana and R. chinensis as well as a very floriferous, black spot resistant tetraploid rose without prickles. PARTICIPANTS: One Iranian doctoral student was trained in the area of molecular markers. In addition, two employees (Natalie Anderson and Henry LaRowe) and four graduate students (Matt Orwat, Amy Tsai, Giuliana Noratto, Valerie Eitriem) have worked on this project. I have also collaborated with both commercial partners (Burchell Nurseries, Modern Agriculture Company-Pico, La Tiesa, Colors, California Tree Fruit Agreement) and public institutions (EMBRAPA, Kasetsart University, USDA, Rutgers University, INRA, Yunnan Academy of Agricultural Sciences, Zhengzhou Fruit Research Institute, Hebrew University) in various aspects of my project. TARGET AUDIENCES: Releases and information developed by the applied stone fruit and rose breeding programs are developments for the farmers, nursery industry, and gardeners in Texas and in areas of similar environments. This information is distributed via talks at various garden and hobby fruit groups, Agrilife Extension, TAMU Agricultural Communications as well as through commercial partners. The scientific information developed in the areas of stone fruit and rose geentics and the health benefits of stone fruit is aimed at the scientific community. It is distributed via referred scientific journals, national/international scientific meetings, and occasional articles in the popular press.

Impacts
The development of medium and low chill Prunus varieties will open up the southern regions of the country for peach production advancing the commercial harvest by 2-3 weeks. The revelation that the main phenolic acids in the active fraction that is responsible to the differential antiproliferative effect on the MDA-MB-435 cells are chlorogenic acid and neo-chlorogenic acid has important clinical implications as these are widespread among food plants including vegetables and fruits and constitute an integral part of the human diet. Disease resistant rose varieties would expand the market for roses as a landscape plant and reduce the amount of pest and disease control chemicals needed to maintain the plants' health.

Publications

Vizzotto, M., L. Cisneros, W. R. Okie, D. W. Ramming, and D. H. Byrne. 2007. Large variation found in the phytochemical content and antioxidant activity of peach and plum germplasm. J. Amer. Soc. Hort. Sci., 132: 334-340.
Byrne, D. H. 2007. Molecular marker use in perennial plant breeding in fruit and ornamental crops. Acta Hort. 751:163-168.
Anderson, N. and D. H. Byrne. 2007. Methods for rose germination. Acta Hort. 751:503-507.
Shupert, D. A., D. H. Byrne, and H. B. Pemberton. 2007. The inheritance of flower traits, leaflet number and prickles in rose. Acta Hort. 751:331-336.
Byrne, D. H., N. Anderson, and H. B. Pemberton. 2007. The use of Rosa wichurana in the development of landscape roses adapted to hot humid climates. Acta Hort. 751:267-274.
Hess, G., C. Scheuring, D. Byrne, and H. Zhang. 2007. Towards positional cloning of the everblooming gene in plants: A BAC library of Rosa chinensis cv. Old Blush. Acta Hort. 751:169-174.

Progress 01/01/06 to 12/31/06

Outputs
This past year 6 peach selections for the low chill zone and 24 peach and 4 nectarines for the medium chill zone were made. The selections this year contained several that were low acid, white, and/or pantao types. Collaborative efforts with breeders around the world especially in Brazil, has broadened the germplasm being used to develop better non melting, red flesh, and high soluble solids peaches and nectarines. Twenty medium chill selections have been propagated for a 3rd stage test in Texas and Georgia. Four low chill peaches have been approved for release for use in Thailand. These will be trademarked for sale in the USA. In studies on the antiproliferative activity of peach and plum phytochemicals on breast cancer, the partial fractionation of the methanolic extract of a peach indicated that the most bioactive fraction was the fraction containing phenolic acids followed by that containing the anthocyanins. The mechanism causing the apoptosis in the breast cancer cell culture is being elucidated. After two years of peach embryo rescue experiments, it appeared that WPM media worked best when it was made from scratch as opposed to bought commercially. Two rose selections are being propagated for 3rd stage evaluation trials. We have screened about 120 SSR primers (of 200 SSR primers available) on both the rose variety collection and two rose mapping populations (WOB26 BC landscape and GGxFC cut rose populations) for band clarity and polymorphisms. About 50 primers appear to be polymorphic for both mapping populations and will be characterized for these. Working with Sriyani Rajapakse, we have developed an initial consolidated rose map which incorporates the tetraploid Clemson-TAMU map, with diploid maps developed in France and Germany

Impacts
The development of medium and low chill Prunus varieties will open up the southern regions of the country for peach production advancing the commercial harvest by 2-3 weeks. Disease resistance rose varieties would expand the market for roses as a landscape plant and reduce the amount of pest and disease control chemicals needed to maintain plant health.

Publications

Thaipong, K., U. Boonprakob, K. Crosby, L. Cisneros-Zevallos, and D. H. Byrne. 2006. Comparison of ABTS, DPPH, FRAP, and ORAC assays for estimating antioxidant activity from guava fruit extracts. J. Food Composition and Anal. 19:669-675.
Burrell, A. M., R. D. Lineberger, K. S. Rathore, and D. H. Byrne. 2006. Genetic variation in somatic embryogenesis of rose. HortScience 41(5):
Vizzotto, M., L. Cisneros, W. R. Okie, D. W. Ramming, and D. H. Byrne. 2006. Large variation found in the phytochemical content and antioxidant activity of peach and plum germplasm. J. Amer. Soc. Hort. Sci., in press.

Progress 01/01/05 to 12/31/05

Outputs
This past year 3 peach selections for the low chill zone and 14 peach and 7 nectarines for the medium chill zone were made. The selections this year contained several that were low acid, white, and/or pantao types. Collaborative efforts with breeders around the world especially in Brazil, has broadened the germplasm being used to develop better non melting, red flesh, and high soluble solids peaches and nectarines. Seven medium chill selections have been propagated for a commercial test. One medium chill peach (Victor) has been released for commercial use in Spain and Australia. Seven peach and plum genotypes were screened for their antiproliferative activity against several breast cell lines. All had excellent antiproliferative activity against the breast cancer cell line MDA-MB-435 but no antiproliferative activity against the MCF-10A normal breast cell line. Partial fractionation of the crude extract indicated that the most bioactive fraction was the fraction containing phenolic acids followed by that containing the anthocyanins. In peach embryo rescue experiments, it appeared that WPM media worked best when it was made from scratch as opposed to bought commercially. The ability of an embryo to be stored in the fruit in a cold room (4 C) was related to the embryo size. The smaller embryos (3-9 mm length) had a decrease in survival after 3 weeks whereas large embryos (>10 mm) could be stored up to 7 weeks before embryo rescue with no decrease in survival. Initial phenotypic data on the WOB backcross populations (Old Blush x (Basyes Thornless x Old Blush)) was analyzed. It showed that flower color, prickle presence, and flower form was inherited as previously reported whereas the everblooming trait had a deficiency of the everblooming genotypes. Most of the quantitative traits (leaflet size, petal size, flower size, flowers per cluster, black spot resistance) were inherited in an additive fashion. DNA was extracted from the WOB26-BC population as well as 80 rose genotypes for characterization with SSRs. We are working with an Israeli partner on creating a map of the rose. A BiBAC library was developed from Old Blush as a first step to characterize the evb gene in rose. Three rose selections were propagated further to begin larger trials to develop the necessary data for a rose variety release.

Impacts
The development of medium and low chill Prunus varieties will open up the southern regions of the country for peach production advancing the commercial harvest by 2-3 weeks. Disease resistance rose varieties would expand the market for roses as a landscape plant and reduce the amount of pest and disease control chemicals needed to maintain plant health.

Publications

Byrne, D. H. 2005. Trends in stone fruit cultivar development. HortTechnology, 15(3):494-500.
Cevallos-Casals, B., D. Byrne, W. R. Okie, and L. Cisneros-Zevallos. 2006. Selecting new peach and plum genotypes rich in phenolic compounds and enhanced functional properties. Food Chem. 96: 273-280.
Bacon, T. A. and D. H. Byrne. 2005. Percent Dry Weight of the Ovule Predicts Peach Seed Viability. HortSci., 40(7):2211-2212.
Zhang, L. H., D. H. Byrne, R. E. Ballard, and S. Rajapakse. 2005. Microsatellite marker development in rose and its application in tetraploid mapping. J. Amer. Soc. Hort. Sci., in press.
Vizzotto, M. 2005. Inhibition of invasive breast cancer cells by selected peach and plum phenolic antioxidants. Ph.D. dissertation. August, 2005.
Shupert, D. 2005. Inheritance of flower, stem, leaf and disease traits in three diploid interspecific populations. M. S. thesis. August, 2005.

Progress 01/01/04 to 12/31/04

Outputs
One medium chill early ripening peach (450 chill unit requirement, ripening with Maycrest) and three low chill peaches (<250 chilling unit requirement, ripening in April and May) are being prepared for release. This past year 4 peach and 2 nectarine selections for the low chill zone and 28 peach and 9 nectarines for the medium chill zone were made. The selections this year contained several that were low acid, white, and/or pantao types. Inbreeding analyses have been done on the commercial fresh market peach varieties used in China and Brazil which indicated that these materials are less inbred than either the East coast fresh market peach cultivars or the fresh market peaches released by the program in Florida. About 60 peach and plum samples were analyzed for anthocyanins, carotenes, phenolics, and antioxidant content. Seven selected genotypes were screened for their inhibition of the growth of several breast cancer cell lines and the genotype with the greatest effect was further fractionated to identify the specific chemicals responsible for this inhibitory effect. Guava fruit extracts were analyzed for ascorbic acid, total phenolics, carotenoids and hydrophilic and lipophilic antioxidant activities. Hydrophilic antioxidant activities determined by all assays was well correlated with ascorbic acid and total phenolics and also among themselves but had negative correlation with total carotenoids. Patents for the "TexKing" (USPP 14,627) and the "TexPrince" (USPP 14.629) peaches were granted on March 23, 2004.

Impacts
The development of medium and low chill Prunus varieties will open up the southern regions of the country for peach production advancing the commercial harvest by 2-3 weeks. Disease resistance rose varieties would expand the market for roses as a landscape plant and reduce the amount of pest and disease control chemicals needed to maintain the plants health.

Publications

Byrne, D. H. and Bacon, T. A. 2004. TexKing, an early ripening medium chill peach. HortScience 39: Byrne, D. H. and Bacon, T. A. 2004. TexPrince, a mid season medium chill peach. HortScience 39(3):631-632.
Kim, C. K., Chung, J. D., Park, S. H., Burrell, A. M., Kamo, K. K., and Byrne, D. H. 2004. Agrobacterium tumefaciens-mediated transformation of Rosa hybrida using the green fluorescent protein (GFP) gene. Plant Cell, Tissue and Organ Culture 78:107-111.
Kim. C. K., Oh, J. Y., Chung, J. D., Burrell, A. M., and Byrne, D. H. 2004. Somatic embryogenesis and plant regeneration from in vitro-grown leaf explants of rose. HortScience 39(6:
Byrne, D. H and T. A. Bacon. 2002. TexKing. Patent application submitted on March 28, 2002. Granted on March 23, 2004. USPP 14,627.
Byrne, D. H. and T. A. Bacon. 2002. TexPrince. Patent application submitted on March 28, 2002. Granted on March 23, 2004. USPP 14,629.
Byrne, D. H. 2004. Development of Landscape roses for southern climates at Texas A&M University. HortScience 39(4):719-720.
Byrne, D. H. 2004. Trends and fashions in fruit cultivar development. HortScience 39(4):726.
Byrne, D. H., Vizzotto, M., Cisneros-Zevallos, L., Ramming, D. W., and Okie, W. R.. 2004. Antioxidant content of peach and plum genotypes. HortScience 39(4):798.
Shupert, D., Anderson, N., and Byrne, D. H. 2004. The inheritance of several traits in three diploid interspecific rose populations. HortScience 39(4):807-808.
Anderson, N. and Byrne, D. H. 2004. Stratification methods for Rosa germination. HortScience 39(4):808.
Lea, M. A., Sura, M., Abichandani, A., desBordes, C., Vizzotto, M., and Byrne, D. H. 2004. Inhibitory effects of anthocyanins on histone methylation and block of cytokinensis by extracts of anthocyanin-enriched fruits and vegetables. American Institute of Cancer Research Annual Meeting.

Progress 01/01/03 to 12/31/03

Outputs
Patents on the two new medium chill peach varieties (TexKing and TexPrince) were granted. TexKing is an early ripening yellow-fleshed peach that ripens after Flordaking and requires about 450 chilling hours to fruit. TexPrince requires 550 chilling hours to fruit well and will replace Junegold and Juneprince in areas that have insufficient chilling accumulation for these commercial varieties. This past year 6 low chill, 18 medium chill, and 8 high chill selections were made. These selections ripen from mid April to early July. The selections this year contained several with total soluble solids of greater than 18 brix and a series of medium chill nectarines. Twenty-two peach varieties and 53 plum varieties with different flesh and skin color were analyzed for antioxidant activity and total phenolics, anthocyanins, and carotenoids. Red fleshed peaches and plums generally had greater levels of anthocyanin and phenolic compounds and antioxidant activity than white or yellow-flesh peaches. Carotenoid content was higher in yellow-flesh (2-3 mg B-carotene /100 g fresh weight) than in white or red-flesh peaches (0.01-1.8 mg B-carotene/100 g fresh weight). These results suggest that red-flesh stone fruit varieties have a greater potential health benefit based on antioxidant content and antioxidant activity as compared to the white and yellow-flesh varieties. Experimentation in somatic embryogenesis and regeneration of roses indicated that the ability of roses to regenerate is genetically determined, that the green fluorescent gene can be used as a marker to identify transformants in the rose transformation system, and that somatic embryogenesis is efficient with the varieties Tournament of Roses and the Fourth of July using in vitro grown leaf explants. Rose seed germination was equivalent with bag stratification as compared to stratification directly in the seedling plots. Nevertheless stratification directly in the flats is preferred because seedling survival is greater.

Impacts
The development of medium and low chill Prunus varieties will open up the southern regions of the country for peach production advancing the commercial harvest by 2-3 weeks. Disease resistance rose varieties would expand the market for roses as a landscape plant and reduce the amount of pest and disease control chemicals needed to maintain the plants health.

Publications

Ma, Y. and D. H. Byrne. 2003. Rose karyology, p. 267-272. Rose Encyclopedia. Elsevier.
Byrne, D. H. and Y. Ma, 2003. Meiosis, p. 273-279. Rose Encyclopedia. Elvesier.
Byrne, D. H. and Y. Ma. 2003. Amphidiploidy, p. 11-15. Rose Encyclopedia. Elsevier.
Byrne, D. H. 2003. Marker-assisted selection, p. 350-357. Rose Encyclopedia. Elsevier.
Promchot, S., U. Boonprakob, and D. H. Byrne. 2002. Influences of Nemaguard and White Angkhang seedling rootstocks on early growth, yield efficiency and fruit quality of low-chill peaches and nectarines in northern Thailand. Thai J. Agric. Sci. 35(4):391-396.
Byrne, D. H. 2003. Founding clones of low chilling fresh market peach germplasm developed in the USA and Brazil. Acta Hort. 606:17-21.
Byrne, D. H. 2003. The use of Prunus mume in the development of low chill apricot varieties: The status of work in the United States. Beijing Forestry Journal 25 (Special issue):15-16.
Sinclair, J. W. and D. H. Byrne. 2003. In vitro growth of immature peach embryos as related to carbohydrate source. HortScience 38(4):582-585.

Progress 01/01/02 to 12/31/02

Outputs
Two medium-chill peach varieties are in the process of being released. 'TexKing' is an early ripening yellow-fleshed peach that ripens after 'Flordaking' and requires about 450 chilling hours to fruit. 'TexPrince' requires 550 chilling hours to fruit well and will replace 'Junegold' and 'Juneprince' in areas that have insufficient chilling accumulation for these commercial varieties. This past year 31 medium chill selections were made that ripen from May to July. The first of a series of orange-fleshed selections were made. Continued work with the antioxidant properties of peach and plum indicates that the phenolics contribute more antioxidant capacity of the fruit than does Vitamin C. Studies of 7 varieties of mayhaw indicated that they ranged widely in their content of carotenoids (lutein, B-carotene, and neoxanthin), phenolics, and anthocyanins. The variety with the highest antioxidant activity (4682 ug Trolox eq/g) also had the highest phenolic content. Cooler temperatures during the germination of embryo rescued peach seed increased the survival of the seed. Germination studies in rose indicate that spaghnum moss is the stratification media that promotes the best seedling germination. In the development of an efficient transformation system for rose, the main limitation is the inconsistent ability of roses to regenerate via somatic embryogenesis. The genetic component of this response was studied in a progeny of a cross between a rose that is easy to regenerate ('Tournament of Roses') and one that is difficult to regenerate ('Baby Love'). The seedlings showed a range of regenerability from as poor as the worst parent to as good as the best parent confirming the genetic basis of this response. Back crosses are being made to further study the genetics of regenerability.

Impacts
The development of medium and low chill Prunus varieties will open up the southern regions of the country for peach production advancing the commercial harvest by 2-3 weeks. Disease resistance rose varieties would expand the market for roses as a landscape plant and reduce the amount of pest and disease control chemicals needed to maintain the plants' health.

Publications

Anderson, N., D. H. Byrne, J. Sinclair, and A. M. Burrell. 2002. Cooler temperatures during germination improves the survival of embryo cultured peach seed. HortScience 37:402-403.

Progress 01/01/01 to 12/31/01

Outputs
One low chill peach was released and two medium-chill peaches are in the release process. A few early ripening peach/nectarine selections were made that had soluble solid content greater than 17 brix. This is a large advance as commercial varieties ripening in May or earlier have soluble solids content of less than 12 brix. About 20 peach and nectarine selections were made and propagated for further evaluation at multiple sites. Continued research into the phytochemicals in red-fleshed peaches and plums confirmed that the plums had higher levels of anthocyanins, phenolics, and antioxidant activity than peaches. Preliminary studies into the tumor inhibition activity indicated that extracts from plums had higher inhibition activity that extracts from blueberry, peaches, carrots or maize. Embryo rescue work indicated that activated charcoal generally had no effect or improved the survival of immature peach embryos during the standard embryo rescue technique. A preliminary rose map was constructed with Dr. Rajapakse of Clemson University. Rose seed germination studies indicated that that germination was better if the seed was stratified in spaghnum moss as compared to perlite, vermiculite, or filter paper. Eighteen tetraploid rose genotypes were screened for their ability to produce embryogenic callus. The three best genotypes were "Fourth of July", "Tournament of Roses" and "Carefree Beauty". Of the fourteen rose species that were screened for their ability to develop embryogenic callus, only two (R. chinensis and R. multiflora) were promising. Putative rose transformants were recovered using co-cultivation with Agrobacterium and the gfp marker system.

Impacts
The development of medium and low chill Prunus varieties will open up the southern regions of the country for peach production advancing the commercial harvest by 2-3 weeks. Disease resistance rose varieties would expand the market for roses as a landscape plant and reduce the amount of pest and disease control chemicals needed to maintain the plants' health.

Publications

BOONPRAKOB, U., D. H. BYRNE, C.J. GRAHAM, W.R. OKIE, T. BECKMAN, and B. R. SMITH. 2001. Genetic relationships among cultivated diploid plums and their progenitors as determined by RAPD markers. J. Amer. Soc. Hort. Sci. 126:451-461.
RAJAPAKSE, S., D. H. BYRNE, L. ZHANG, N. ANDERSON, K. ARUMUGANATHAN, and R.E. BALLARD. 2001. Two genetic linkage maps of tetraploid roses. Theor. Appl. Genet. 103:575-583.
RAJAPAKSE, S., L. ZHANG, R.E. BALLARD, and D.H. BYRNE. 2001. AFLP marker development in rose for genetic mapping: comparison of three restriction enzyme pairs. Acta Hort. 546:619-627.

Progress 01/01/00 to 12/31/00

Outputs
A trip was made to the four Prunus Repositories in China and 19 seed and 34 clonal accessions were collected and given to the Plant Quarantine Service for pathogen screening. One low chill peach is being released and two medium-chill peaches are in the release process. Texas had another mild winter, which made it a good year for selection for low chilling adaptation. About 30 peach and nectarine selections were made and propagated for further evaluation at multiple sites. Initial survey study of the phytochemicals in red-fleshed peaches and plums showed a wide range in both phenolic and anthocyanin content with the highest level of both chemicals in the plums. Correlation studies showed that the level of anthocyanins was correlated with antioxidant activity. Embryo rescue work focussed on the effect of various sucrose and fructose combinations and activated charcoal on survival. A preliminary rose map was constructed with Dr. Rajapakse of Clemson University. Rose seed germination studies indicated that leaching for more than 3 days was detrimental and that germination was better if the seed was stratified in spaghnum moss as compared to agar or filter paper. Ten tetraploid rose genotypes were screened for their ability to produce embryogenic callus. The two best genotypes were "Tournament of Roses" and "Carefree Beauty".

Impacts
The development of medium and low chill Prunus varieties will open up the southern regions of the country for peach production advancing the commercial harvest by 2-3 weeks. Disease resistance rose varieties would expand the market for roses as a landscape plant and reduce the amount of pest and disease control chemicals needed to maintain the plants' health.

Publications

BYRNE, D. H., W. B. SHERMAN, and T. A. BACON. 2000. Stone fruit genetic pool and its exploitation for growing under warm climatic conditions. In: Erez, A. (ed.). Temperate Fruit Crops in Warm Climates. Kluwer Academic Publishers.

Progress 01/01/99 to 12/31/99

Outputs
The past year was an unusually low chill year for Texas and thus was a good opportunity to select for low chill adaptation among the stone fruit breeding populations. Twenty-five peach and nectarine selections were made. These ranged in fruit development period from 60 to 134 days and in chilling requirement from 150 to 650 chilling units. One low chill and 4 medium chill selections are being prepared for release. Studies of peach embryo rescue focussed on the effect of sucrose and fructose combined with other sugars on the germination and survival of immature peach embryos. Sucrose and fructose alone or combined with each other or sucrose worked well although the results varied with the genotype tested. Germination of embryos from in vitro rescue was better at 20C as compared to 28C, confirming the initial results from the previous year. The final evaluations were done on the 50 peach, plum, and peach assessions from the USDA Clonal Germplasm Repository. The most consistently fruiting were the plum 731A, and the peaches 672A and 1664 followed by apricot 1773, and two peaches, 1607 and 1610A. None had commercially acceptable fruit. Work with Dr. Rajapaske (Clemson University) has resulted in an initial map of a tetraploid F2 population. Bulked segregant analysis has begun to locate markers linked to the genes that condition the everblooming trait, powdery mildew resistance, and prickles. The DNA pools were developed from the segregants of a F2 population of the hybrid between Basye Wichuraiana and Old Blush. The Back cross population is germinating and will be used to confirm linkage of the markers identified.

Impacts
The stone fruit breeding work is resulting a series of peach cultivars ripening from April to mid June that will make the commercial production of peaches in the southern regions of the USA a potentially lucrative endeavor. The rose work is progressing towards disease resistant landscape roses to reduce the care and potential hazards of pesticides.

Publications

BYRNE, D. H. AND BACON, T. A. 1999. Founding clones of low-chill fresh market peach germplasm. Fruit Var. J. 53: 162-171.
JAN, C. H., D. H. BYRNE, J. MANHART, AND H. WILSON. 1999. Rose germplasm amalysis with RAPD markers. HortScience 34: 341-345.
SOUZA, V. A. B., BYRNE, D. H. and TAYLOR, J. F. 2000. Predicted breeding values for nine plant and fruit characteristics of 28 peach genotypes. J. Amer. Soc. Hort. Sci. 125: in press.
MA, Y., C. F. CRANE, and BYRNE, D. H. 2000. Meiotic behavior of a tetraploid rose and its hybrid progeny. HortScience 35, in press.

Progress 01/01/98 to 12/31/98

Outputs
Twenty-three peach, one apricot, and two rootstock selections were made and have been propagated for further evaluation. The effect of the sugar source (sucrose, sorbitol, fructose, and maltose at 2% and 3% levels), pH, and buffering concentration of the media on immature embryo growth, and effect of temperature (18C vs. 28C) on peach embryo cultures during the germination stage on subsequent plant growth and survival was assessed. The lower temperature favored embryo growth as did the 2% level of most of the sugars tested with the exception of maltose, which caused very poor survival. Fruit characteristics, bloom dates, and disease resistance was evaluated on 50 peach, plum, and peach assessions from the USDA Clonal Germplasm Repository. Of these the most consistently fruiting are the plum 731A, and the peaches 672A and 1664. Genotypes that fruited for the first time this year include the apricot 1773, and two peaches, 1607 and 1610A. None had commercially acceptable fruit. Initial crosses between apricot and Prunus mume, a low chill apricot relative, were done to develop low chill and consistently fruiting apricots for subtropical zones. Work has begun to develop a map of the rose genome using both diploid and tetraploid mapping populations. Traits of interest for mapping and marker development are powdery mildew resistance, black spot resistance, thornlessness, flower color, petal number, fragrance, and other horticultural traits. Several of the progenies for these studies are being created in cooperation with commercial companies. The ability to propagate roses in vitro has been developed for several additional species hybrids and these are being treated with oryzalin to double their chromosome number. The rose varieties Thornless Wichuraiana and Old Blush have been transformed using the Agrobacterium-mediated meristem transformation system. This work is being extended to additional genotypes and genes.

Impacts
(N/A)

Publications

Ma, Y., Crane, C.F., and Byrne, D.H. 1997. Karyotypic relationships among some Rosa species. Caryologia 50(3-4):317-326.
Rizzo, M., Porter, K., Bassi, D. and Byrne, D.H. 1997. Growth of immature peach [Prunus persica (L.) Batsch.] embryos on different media. Acta Hort., in press.
Souza, V. A. B., Byrne, D. H. and Taylor, J. F. 1998. Heritability, genetic and phenotypic correlations, and predicted selection response of quantitative traits in peach: I. An analysis of several reproductive traits. J. Amer. Soc. Hort. Sci. 123(4):598-603.
Souza, V. A. B., Byrne, D. H., and Taylor, J. F. 1998. Heritability, genetic and phenotypic correlations, and predicted selection response of quantitative traits in peach: II. An analysis of several fruit traits. J. Amer. Soc. Hort. Sci. 123(4):604-611.
Jan, C. H., Byrne, D. H., Manhart, J. and Wilson, H. 1998. Rose germplasm analysis with RAPD markers. HortScience, in press.
Byrne, D. H. and Ma, Y. 1998. Affinities of Rosa roxburghii Tratt. (Abstract). HortScience 33:493.
Ma, Y. and Byrne, D. H. 1998. Meiotic behavior in an amphidiploid rose and its hybrid progeny. (Abstract). HortScience 33: 483
Byrne, D. H., Rizzo, M. Porter, K. Ramming, D. Anderson, N. and Sinclair, J. 1998. In ovule culture in peach: embryo perforation, duration of culture, and media effects on seed growth and seedling survival. (Abstract). HortScience 33: 460.

Progress 01/01/97 to 12/31/97

Outputs
Medium chill apricot, low chill mume, low acid peach/nectarine, and disease resistant roses were collected as seed and pollen for breeding work. Initial hybridizations were done to incorporate the low acid gene into our medium chill peach/nectarine breeding population. About 30 peach and nectarine selections were made and propagated for further evaluation. The final selections from the low chill program based in south Texas were made and the selections were propagated for further evaluation. Fruit characteristics, bloom dates, and bacterial leaf spot resistance was evaluated for fifty peach, apricot, and plum accessions from the USDA Clonal Germplasm Repository. Only five genotypes, two plums (731A, 791A, ) and three peaches (1664, 672A, 1665) fruited well. Of the plums only 731A was healthy. The plum 791A is susceptible to rust and plum scorch. Both 672A and 1665 are low acid peaches which lack in size, color and firmness but set heavy crops. The peach 1664 is a productive tree with medium size non melting clingstone peaches. None of the other genotypes fruited well in this medium chill zone. Founding clone analysis of low chill peach germplasm indicated that the germplasm developed in Florida and that developed in Brazil are significantly different. The mapped plum population was established in the field for further horticultural evaluation and the production of the F2 population. About 10 rose selections were made from the hybrid progeny derived from crosses between the Basye breeding lines and commercial cultivars. Seed to establish the F2 generation was collected. A trip to China was made to collect germplasm and establish contacts there to develop cooperative research programs. Initial research in rose transformation using the Agrobacterium-mediated meristem system has yielded a high rate of transformation.

Impacts
(N/A)

Publications

FINCH, C., BYRNE, D.H., LYONS, C. and H. DALE PENNINGTON. 1997. Sulfur nutrition requirements of PEACH TREES. J. Plant Nutr. 20(12): 1711-1721.
MA, Y., CRANE, C.F., and BYRNE, D.H. 1996. Meiotic behavior of hybrids involving Rosa laevigata. Cytologia 61:457-463.
MA, Y., CRANE, C.F., and BYRNE, D.H. 1997. Karyotypic relationships among some Rosa species. Caryologia, in press.
STRONG, K, and BYRNE, D. H. 1995. Performance of low-chill Japanese plums in subtropical Texas. Subtropical Plant Sci. 47:30-33.
SUDAHONO, BYRNE, D. H., and ROUSE, R. E. 1995. Field tolerance of citrus rootstocks to calcareous soils. Subtropical Plant Sci. 47:7-11.
KIM, Y. J. and BYRNE, D. H. 1996. Interspecific hybrid verification of Rosa with isozymes. HortScience 31(7):1207-1209.
MA, Y. , ISLAM-FARIDI, M. N., CRANE, C. F., JI, X., STELLY, D. M., PRICE, H. J., and BYRNE, D. H. 1997. In situ hybridization of ribosomal DNA to rose chromosomes. J. Hered. 88(2):158-161.
MA, Y., BYRNE, D.H., and CHEN, J. 1997. Amphidiploid induction from diploid rose interspecific hybrids. HortScience 32(2):292-295.

Progress 01/01/96 to 12/30/96

Outputs
Ten low and medium chill peach / nectarine selections were propagated for further evaluation. In ovule culture experiments with early ripening peach cultivars indicated that seed perforation although it increases the growth of the ovule, it decreases the survival of the rescued embryos as compared to no perforation. Embryo rescue experiments showed that the WPM was better than either MS or Knops media. In peach, high heritabilities were found for full bloom date, ripe date, fruit development period and percent blush and intermediate heritability was found for fruit weight, fruit shape, and fruit tip. RAPD markers were used to study the variability and genetic relationships among the cultivated plum. This data a close relationship among the founding parents derived from Burbank#s breeding program. All the cultivated clones examined were easily distinguished with the RAPD markers and a preliminary genetic map for the plum was constructed using RAPD markers and isozymes. An additional 80 rose accessions were evaluated for resistance to blackspot. A series of hybrids have been created between the amphidiploids and commercial rose germplasm. Isozymes markers were shown to be useful in the verification of hybridity. RAPD markers easily distinguished among rose species and indicated that R. roxburghii and R. minutifolia which are classified in separate subgenera, are more appropriately classified within the subgenus Rosa.

Impacts
(N/A)

Publications

BYRNE, D. H., BLACK, W. , MA, Y. , and PEMBERTON, H.B.. 1996. The use of amphidiploidy in the development of blackspot resistant rose germplasm. Acta Hort., 424:269-272.
MA, Y., BYRNE, D. H., and CHEN, J. 1996. Propagation of rose species in vitro.
IVCDB, 32:103-108.
BOONPRAKOB, U., BYRNE, D. H., and MUELLER, D. M. J. 1996. Anatomical differencesof axillary bud development in blind nodes and normal nodes in `EarliGrande' and`June Gold' peach. HortScience 31(5):798-801.
MA, Y. , ISLAM-FARIDI, M. N., CRANE, C. F., STELLY, D. M., PRICE, H. J., and BYRNE, D. H. 1996. A new procedure to prepare slides of metaphase chromosomes ofroses. HortScience 31(5):855-857.
STRONG, K, and BYRNE, D. H. 1996. Performance of low-chill Japanese plums in subtropical Texas. J. Subtropical Horticulture, in press.
SUDAHONO, BYRNE, D. H., and ROUSE, R. E. 1996. Field tolerance of citrus rootstocks to calcareous soils. J. Subtropical Horticulture, in press.
KIM, Y. J. and BYRNE, D. H. 1997. Interspecific hybrid verification of Rosa withisozymes. HortScience, in press.
MA, Y. , ISLAM-FARIDI, M. N., CRANE, C. F., JI, X., STELLY, D. M., PRICE, H. J.,and BYRNE, D. H. 1997. In situ hybridization of ribosomal DNA to rose chromosomes. J. Hered., in press.

Progress 01/01/95 to 12/30/95

Outputs
Ten low and 15 medium chill peach/nectarine selections were propagated for further evaluation. Genetic studies of peach progenies indicates that full bloom date, ripe date, fruit development period and percent blush are highly heritable, and fruit weight, fruit shape, and fruit tip have an intermediate level of heritability. RAPD marker data for diploid Japanese plums (P. salicina) indicates that the California germplasm is less variable than the plum germplasm developed in the southeastern USA. Genetic distances among the cultivated plums ranged from 0.32 to 0.68 and the relationships among the related species as determined by the RAPD data agreed well with the natural geographic distribution. The ovule percent dry weight is an excellent predictor of peach seed survival and the need for embryo rescue techniques. 160 rose accessions were evaluated for resistance to blackspot. The best sources of resistance was among the diploid rose species. Amphidiploids developed from these species have shown fair to good fertility. Using an in vitro colchicine technique another 10 amphidiploids have been created. Protected/unprotected studies showed that susceptible and highly resistant roses grew 90% and 0% less after one year due to blackspot infection. Isooqymes (MDH, PGI, 6PGD, ACP) were highly variable among rose species and indicated that R. roxburghii which is classified in a separate subgenera, is more appropriatelly classified with the subgenera Rosa.

Impacts
(N/A)

Publications

Progress 01/01/94 to 12/30/94

Outputs
Four low chill, 27 medium chill, and 100 Prunus clones from the Clonal GermplasmRepository were propagated for further fruit quality and adaptation evaluation field trials. The analysis of the genetic inheritance of important qualitative traits in segregating peach progenies is revealing a high level of heritability in several traits of great economic importance (precocity, ripening period, bloom time). Twenty plum cultivars have been characterized with RAPD markers. Of eighty oligodecamers screened, 57 gave successful reactions with two to three bands per primer. A high level of polymorphisms was detected. Several apricot x mume progenies were developed in an effort to incorporate the low chilling adaptation of the mume into apricot germplasm. Another 20 rootstocks were planted in the field trial to evaluate them for resistance to chlorosis in calcareous soil. The first trial showed that Okinawa, Flordaguard, Cotton and Petit were very susceptible, Montclar and RRL-IN were moderately tolerant, and GF677 was tolerant to chlorosis development in calcareous soil.

Impacts
(N/A)

Publications

Progress 01/01/93 to 12/30/93

Outputs
Four low chill and 8 medium chill advanced peach selections were propagated for commercial trial. Fruiting and tree health evaluations were done on 250 clones and 8,000 progenies of peach, plum and apricot. Thirty-five selections were made and 4,000 seedlings were planted in the medium and low-chill regions. Analysis of the isozyme variability of the diploid Japanese plum germplasm in the USA indicated that the germplasm developed in the southeastern states has 2-3 times more variability than the California germplasm. This is due to the use of an unique source of Prunus salicina as a source of low chilling and the use of P. cerasifera and P. angustifolia as sources of disease resistance in the breeding in the southeast. The plum germplasm is being screened for variability of RAPD markers. Of the 100 probes screened thus far, approximately 60% gave clearly read banding patterns. Apricot x P. mume hybrids were created to incorporate low chilling and disease resistance into apricot germplasm. The field trial of peach rootstocks for chlorosis tolerance in calcareous soil is confirming the results obtained from the greenhouse screening with high bicarbonate solution.

Impacts
(N/A)

Publications

Progress 01/01/92 to 12/30/92

Outputs
Over 300 clones and 10,000 peach, plum and apricot seedlings were evaluated in the medium (College Station, Yoakum) and low chill (Weslaco, Linn) regions for tree health and fruiting characteristics. 1500 and 5000 seedlings were planted in the low chill and medium chill regions respectively. Approximately 50 selections were made and over a dozen advanced selections were propagated for second stage evaluation. A regional trial in the 650-800 chilling region was established. Preliminary analysis of MDH, PGI, and PGM in plum and of EST in apricot indicates codominant inheritance. Variability in RAPDs has been detected in peach, plum, and apricot. Of the rootstocks in a field trial in south Texas, Hansen, Lovell, and Halford were more precocious in the third leaf than were Nemaguard and Nemared. Field trials to confirm the greenhouse ratings of tolerance to lime-induced chlorosis have been planted.

Impacts
(N/A)

Publications

Progress 01/01/91 to 12/30/91

Outputs
Fruit and tree evaluations were done on clonal collections and seedling progeny in both the medium-chilling (College Station, Yoakum) and the low-chilling regions. "TexRoyal" a 600-chilling hour cultivar was released and 10 selections were made from the seedling plots. Six thousand seedlings were planted and 12,000 seeds were collected and stratified this year. A regional trial was organized to test breeding lines and new cultivars for north-central Texas. The peach collection was evaluated for the propensity for blind bud formation. Innovations such as ovule perforation, vermiculite support systems and improved media in peach embryo rescue via in ovulo culture increased growth over standard procedures. Regeneration of small citrus apices, stem explants and root explants was successful. Isozyme analysis for interspecific hybrid verification has been routinely employed. Preliminary analyses of isozyme variability among plum germplasm pools has been done. Peach germplasm was surveyed for MNR and MDH.

Impacts
(N/A)

Publications

Progress 01/01/90 to 12/30/90

Outputs
Fruit evaluations were done on clonal collections at Weslaco, Yoakum, and College Station. Fifteen advanced selections from 1986-1989 were propagated for second stage testing. Twenty scion and five rootstock were made in 1990. One selection is in the process of being released and 'ValleGrande' was released. Rapid progress seems possible for selection of 450-650 chill cultivars which crop consistently and have stable round shape under fluctuating chilling conditions (500-900 chill units). 5,000 peach, plum and apricot seedlings were planted at College Station. 5,500 peach and 2,000 plum seeds were stratified from 1990 crosses. These crosses include 1,500 for the subtropical zone and 6,000 for the medium chill zones. A series of plum and peach crosses were made to study inheritance and correlation of isozyme and morphological variants. Crosses were also made to incorporate rust resistance of Mexican peach germplasm into subtropical peach germplasm and in rootstock work to combine the red leaf character, alkalinity tolerance and nematode resistance. Work continued on the electrophoretic variability of plum and peach germplasm. Esterase, shikimate dehydrogenase and MNR staining protocols were modified to give more consistent results. Small peach embryos in inovule culture grew better using a vermiculite support (vs gelrite or filter paper bridge), with 6% sucrose and Steward & Hsu media. Slitting the ovule before culture, increased embryo growth two-fold.

Impacts
(N/A)

Publications

Progress 01/01/89 to 12/30/89

Outputs
Due to a very mild winter, this past year was excellent for the evaluation of tolerance of Prunus to low chill conditions. This was evaluated by comparing their yield, amount button fruit and fruit shape in high and low chill years. Traditionally relative bloom period of peach is associated with the chill required by the genotype. This relationship does not always hold. Late blooming genotypes that fruit under low chill conditions have been identified. Approximately 150 genotypes have been planted or topworked in the orchards and 2,300 segregating Prunus progenies have been planted. About 6,000 seedlings have been planted in the greenhouse from this year's hybridizations. California and Florida plum selections and cultivars have been analyzed for electrophoretic variability. The California germplasm contains little variability whereas the Florida germplasm is highly variable. Procedures for the morphological characterization of this plum material are being developed. Genetic analysis of 5 isozyme loci in apricot was completed and that of plum is in progress. Research on embryo culture of peach concentrated on the effects of embryo size, media, and support media on embryo growth. Screening for alkalinity tolerance of peach rootstocks has identified the highest levels of tolerance in germplasm with some almond background. There is a wide range of alkalinity tolerance among peach germplasm. The levels of sulphur for optimal peach tree growth were determined to be higher than previously reported.

Impacts
(N/A)

Publications

Progress 01/01/88 to 12/30/88

Outputs
Over 100 germplasm accessions were established for evaluation and 40 selections were made from the low medium-chill breeding populations. An extensive database on peach materials and several computer programs are being developed to aid in the hybridization planning process. A pedigree analysis of plum germplasm indicated that little apparent inbreeding has occurred in plum breeding, that several distinct sources of disease resistance are available and the plum germplasm developed in the southeast has a wider genetic base than that developed in California. The species composition of both groups are approximately 50% Prunus salicina although the particular founding clones are different. The 2nd and 3rd most important species in the California plums are P. simonii and P. americana and in the southeastern germplasm is P. cerasifera and P. angustifolia. The mechanism of alkalinity tolerance was determined to be an increased ability of tolerant genotypes to reduce iron at the root surface. Two alkalinity tolerant peach selections were made. Initial surveys of isozyme variability for seven enzymes was completed for peach, plum and apricot, and genetic studies for several isozyme variants were done for peach and apricot. Comparative studies of germplasm variability for isozyme variants are in progress to compare the genetic divesity and relationship among various cultivated and wild germplasm pools.

Impacts
(N/A)

Publications

Progress 01/01/87 to 12/30/87

Outputs
200 germplasm accessions were collected. Five advanced peach selections were propagated and planted in commercial trials this spring. Over 2000 embryo cultures were done this year to accelerate progress in the development of early maturing and low chilling peach materials. Screening for Prunus for salinity, aluminum toxicity and manganese toxicity have been completed. P. mexicana and 'Titan' almond x Nemaguard line showed greater salinity tolerance than Nemaguard, Nemared, P. cerasifera and bitter almond. Although no material screened was more tolerant than Nemaguard or Lovell to aluminum toxicity, P. tomentosa was much more sensitive. All materials screened for manganese toxicity tolerance were uniformly susceptible. There s a need to collect native species and naturals from acid soil areas to locate good sources of tolerance. Materials resistant to alkalinity have been found in almond-derived lines, peach and plum. More emphasis on the peach and plum sources of tolerance should avoid clonal propagation difficulties derived from almond materials. Field trials have shown that tolerant materials were not affected by alkaline conditions whereas susceptible materials experienced leaf chlorosis and a 60% growth reduction. Long-term comparison of 3 common rootstocks in an alkaline soil continue. Several hundred accessions of peach, plum and apricot have been characterized for 12 isozyme loci. Biochemical fingerprinting with isozyme markers is more useful with plum and apricots.

Impacts
(N/A)

Publications

Progress 01/01/86 to 12/30/86

Outputs
Although hybridization efforts were disappointing this year due to adverse spring weather, much germplasm was collected for incorporation into the stone fruit breeding and genetic research program. This included commercial cultivars, advanced selections, and other Prunus materials with particular emphasis on the collection of sources of genes for male sterility, early ripening, good fruit color, alkalinity tolerance and other rootstock characters. Approximately 7,000 seedlings from 200 families were planted in a high density fruiting nursery. Several early selections from the 1983 progeny were made. 500 embryo cultures were done this year with good success. Vermiculite promoted better root growth than agar but both transplanted equally well. A wide range of Prunus material was assayed from isozyme variability with 5 enzyme systems. A preliminary analysis of interspecific variability of isozymes has been completed. A comparative study of enzyme extraction buffers for perennial crops was done. The growth response of peach and other Prunus spp was characterized for several levels of salinity, aluminum and magnanese. A rapid laboratory screening procedure for alkalinity tolerance of seedlings has been developed and a wide range of Prunus is being screened.

Impacts
(N/A)

Publications

Progress 01/01/85 to 12/30/85

Outputs
Breeding for peach scion & rootstocks is progressing well. More than 100 additional materials have been collected, several hundred progenies planted, evaluations done for 350 clonal materials and a rootstock alkalinity tolerance screening stock established. Greenhouse studies are characterizing the growth response of Prunus materials to various stress levels of soil alkalinity, soil acidity and salinity. The flower-frost tolerance of 'Texstar' was characterized as being conditioned by tolerance (high initial flower bud set) and avoidance (long bloom period) mechanisms. Electrophoretic screening for isozyme variants has revealed little variation within Prunus persica but substantial variation among the cultivated Prunus and within Malus domestica. Work correlating fruit color and firmness indicates that flesh color is a better predictor of flesh firmness than skin color.

Impacts
(N/A)

Publications

Progress 01/01/84 to 12/30/84

Outputs
The peach breeding program is progressing well towards its objectives of developing cultivars adapted to chilling zones of 750 hours or lower and of developing rootstocks tolerant to edaphic problems such as alkalinity, salinity, and pathogens. Over 100 clonal materials and 200 progenies are presently being established. This past year 50 Texas selections and 15 out-of-state materials were selected from over 500 peach clones. Preliminary work has detected large differences in flower bud density and flower frost hardiness and variability in isozymes in the Prunus collection. Work correlating fruit color and firmness indicates that flesh color is a better predictor of flesh firmness than skin color.

Impacts
(N/A)

Publications