Progress 10/01/14 to 09/30/19
Outputs
Target Audience:The target audiences include growers, processors, handlers, marketers and consumers of almonds and peaches. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?I have been a Major Professor for four graduate students during this review period and have served as a thesis advisor for an additional 11 graduate students. In addition, I typically mentor one to two student internships per year and I am also currently mentoring two undergraduate student capstone research projects for the Global Disease Biology major. How have the results been disseminated to communities of interest?My research inherently involves considerable outreach teaching and field consultations with growers, processors and consumers. This responsibility requires a significant amount of my time being spent off- campus. While these travels can be very time-consuming, they also keep me current with the needs of the end users. During the review period, I have also been invited to give a number of presentations to industry and national/international research groups. I have served on the UC Research Advisory Committees for Almond and Processing Peach. At the State level, I have served on the FPS Tree Crop Technical Advisory Committee and the L.J. Nickels Trust Research Advisory Committee, and have recently chaired the Walnut Endowment Review Committee. At the national level, I have served on the SCRI FasTrack Program Advisory Committee, USDA National Prunus Crop Germplasm Committee and Chair the Almond Crop Germplasm Subcommittee. What do you plan to do during the next reporting period to accomplish the goals?I plan to continue with established programs as described in these reports
Impacts
What was accomplished under these goals?
Ongoing research on peach and almond cultivation as well as global production trends highlight the vulnerability of these crops due to their narrow germplasm base and restrictive climactic requirements. A very early bloom in February make almond particularly vulnerable to climate change associated anomalous weather patterns such as late spring frosts and deterioration in the winter-chill conditions required to break dormancy. Almond and peach shoots and leaves are similarly highly vulnerable to diseases associated with even moderate levels of late spring and summer moisture, relegating production to strict Mediterranean climates. The status of international breeding goals and research progress has been summarized while an extensive interspecies germplasm for potentially overcoming traditional breeding limitations has been introduced. In a related, ongoing effort, I have also been working with Iranian colleagues on a monograph to be published by CABI, compiling a comprehensive horticultural characterization and genetic/breeding assessment of the large number of wild almond and peach species found in Europe and Asia]. In response to changing climate and market demands, my research priorities emphasize improvements in bloom and harvest performance, disease resistance and fruit/nut quality. In anticipation of continuing progress in normally unrelated agronomic crop breeding efforts to develop apomictic and other forms of true-breeding (i.e. clonal) seed, my program has published a series of papers summarizing our experience in the development of strategies, selection methods, and performance appraisals for epigenetic selection as a complement to genetic/genomic selection for crop improvement. Breeding for climate resilience in almond and peach varieties. With the exception of UCD releases, most commercially important California almond varieties bloom during the last two weeks of February. This is a consequence of their common origin from crosses between the varieties Nonpareil and Mission, both of which probably have a common progenitor. Long-term studies in both Spain and California have documented a serious vulnerability to insufficient chilling as well as the greater . Occurrence of late year spring frosts, both of which are associated with ongoing climate change. Breeding progress towards later blooming varieties has been summarized for different regions, germplasms and selection strategies, allowing the identification of promising germplasm and breeding options. This research identified one of the most promising germplasm for breeding for later bloom as the Tardy-Nonpareil mutation that delays bloom by approximately 10 days but which is also associated with undesirable low tree productivity. With the recently released almond variety Kester we have demonstrated the successful breakage of the linkage between delayed bloom and low productivity in this germplasm. A serious consequence of insufficient chilling for peach production is a protracted bloom that results in long-drawn-out fruit ripening and the need for expensive multiple harvests. Journal articles have described the successful introgression of almond and exotic peach germplasm allowing once-over harvest for the UCD released processing peach varieties Kader and Vilmos. Traits targeted include resistance to flesh-bruising and fruit brown-rot, as well as the preservation of individual fruit mesocarp texture and eating quality for up to 20 days following initial fruit ripening. By extending the tree-life of the first-ripening fruit, the later shaded interior or otherwise lagging fruit could reach full-ripeness as well as maximum fruit mass, allowing a more efficient single-harvest while also optimizing final yields and consumer quality. This stay-ripe trait introduces the capability for single-harvest and when combined with resistance to fruit rot and flesh-bruising, as found in Vilmos and Kader, represent the first processing peach releases bred for mechanical harvest. Breeding for Disease Resistance. Flower blights and subsequent fruit (hull) rots are major sources of crop loss in peach and almond. In peach, these diseases are predominantly caused by Monilinia spp. with both Monilinia and Botrytis present in almond. Domestication bottlenecks and subsequent inbreeding have resulted in limited intraspecific genetic options for resistance to these diseases. Therefore, my program has targeted extensive introgression of interspecific resistance germplasm from wild and related cultivated species. The resulting availability of enhanced genetic variability and associated novel resistance sources was a major impetus for the RosBreed-1 and RosBreed-2 SCRI peach improvement projects where molecular marker and disease phenotype data for over 2000 UCD peach, almond and peach-almond introgression breeding lines have been developed and are being evaluated. While much of this data has only recently become available for analysis, a recently completed analysis has demonstrated promising levels of disease resistance derived from almond and peach species in advanced UCD peach breeding lines. Because of the complexity of both the resistance sources and resistance mechanisms, novel Bayesian analysis approaches were utilized to more effectively characterize promising resistance loci and their species origins. A related report presents a novel bio-reporter approach to disease resistance screening based on results from the long-term collaboration of my breeding program with the Bostock plant pathology program. Because our analysis of promising resistance sources in the diverse UCD interspecies breeding germplasm demonstrated that many of the more promising resistance mechanisms altered the redox environment of the plant-microbial interface, a rapid, noninvasive assay was developed that uses a bacterial bioreporter that responds to ROS and redox-active environments. This assay has improved selection efficiency for blossom and fruit microenvironments associated with improved disease resistance in both laboratory and field conditions. Breeding for improved nutritional quality. Improved nutritional quality in peach is being pursued through the incorporation of the stay-ripe trait in new varieties which, as previously described, allows a larger proportion of orchard fruit to achieve full tree-ripe quality prior to harvest. In almond, improved nutritional quality is being pursued through improved lipid composition as in the high oleic to linoleic acid ratios in the previously released Sweetheart variety and through improved protein composition. Amandin, the predominant storage protein in almond, has also been identified as a nut allergen. Rapid and accurate ELISA-based assays have been developed for amandin that also allow estimation of protein content in different varieties as well as protein stability over extended storage times. In a very promising application of this technology, advanced UCD almond breeding lines representing diverse genetic origins including peach, wild peach species and related wild almond species, have demonstrated immunoreactivity levels of less than half the Nonpareil standard while still maintaining soluble protein levels at the commercially desirable concentrations of approximately 25g/100g DW. The genetic and biochemical basis for these achievements are the focus of ongoing studies. Epigenetic selection. The vegetative propagation of almond and peach varieties and rootstocks can result in long-live clones were epigenetic deterioration becomes commercially important. Consequently, my breeding program has successfully developed strategies for efficient epigenetic selection. We have described successful epigenetic selection strategies for improved clone productivity, recovery of self-compatibility, and the control of Noninfectious Bud-Failure (NBF) in almond.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Liu, Ting-Hang, Mohammad A. Yaghmour, Miin-Huey Lee, Thomas M. Gradziel, Johan Leveau, and Richard M. Bostock. 2019. A roGFP2-based bacterial bioreporter for redox sensing of plant surfaces. Phytopathology September 4, 2019.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Gradziel, Thomas M. and Jonathan Fresnedo-Ram�rez. (2019). Noninfectious Bud-failure As a Model for Studying Age Related Genetic Disorders in Long-Lived Perennial Plants. Journal of the American Pomological Society 73(4): 240-253 2019
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Gradziel, T. M., and. B. Lampinen. 2019. `Kester' Almond: A Pollenizer for the Late `Nonpareil' Bloom with High Yield and Kernel Quality. HORTSCIENCE 54(n):1 -2.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Gradziel, T., and S. Marchand. 2019. `Vilmos' Peach: A Processing Clingstone Peach Expressing a Novel `Stay-Ripe' Trait With Improved Harvest Quality, Ripening In The `Andross' Maturity Season. HORTSCIENCE 54: 2078-2080. 2019.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Gradziel, T. and S. Marchand. 2019. `Kader' Peach: a Processing Clingstone Peach with Improved Harvest Quality and Disease Resistance, Ripening in the `Dixon' Maturity Season. HORTSCIENCE 54(4):754 -757. 2019.
|
Progress 10/01/17 to 09/30/18
Outputs
Target Audience:Research scientists, crop advisors, growers, processors, consultants, consumers. Changes/Problems:Reduction in Hatch support. What opportunities for training and professional development has the project provided?Trained 3 MS students the last year. How have the results been disseminated to communities of interest?Multiple publications, multiple professional presentations and multiple consumer/grower presentations. What do you plan to do during the next reporting period to accomplish the goals?Continue with current strategy as presented in 2014, 5-year plan.
Impacts
What was accomplished under these goals?
The California almond industry is in a period of historic transformation driven by increasing environmental and market demands, reductions in water and other natural resources, loss of natural pollinators, and changing climate. While almond represents a diverse and highly adaptable species, commercial production is dependent almost entirely on the variety Nonpareil and its pollenizers, most of which have Nonpareil and Mission as direct parents. Thus, the goal of the UCD Almond Breeding program is the incorporation of promising new and diverse germplasm to provide new genetic solutions to emerging production challenges. The recent release of Kester as a very productive, high kernel quality pollinizer for later Nonpareil bloom, and Sweetheart as a premium quality, Marcona-type almond possessing partial self-compatibility, very high levels of the heart-healthy phytonutrient oleic-acid, as well as improved resistance to navel orangeworm and aflatoxin contamination, demonstrates the potential of this germplasm. The second generation of UCD breeding selections has now been advanced from multi-year evaluations in regional grower trials to comprehensive, replicated testing at the new Regional Variety Trials (RVT) located in Madera, Stanislaus and Butte counties. These advanced selections combine self-compatibility with improved kernel size, quality and productivity. A range of traditional and novel tree architectures have been included to assess opportunities/risks under new orchard management strategies such as higher planting densities and/or reduced pruning practices. Selections have been chosen for possible single-variety orchards or as pollenizers for the early and late Nonpareil bloom. Consistent bloom overlap occurred in 2016 and 2017 for most RVT selections despite large differences in winter chilling and spring heat units. Most selections also displayed kernel qualities and yields comparable to Nonpareil, though multiple additional years of testing will be required in order to establish accurate trends. Improved genetic diversity in RVT selections as well as third generation breeding selections now moving into grower trials, have been documented through both molecular characterization and through recovery of novel traits including improved disease resistance, high shell-seal with high kernel-to-nut crack out ratios, high self-compatibility combined with high levels of self-pollination, and improved kernel size, phytonutrient content and reduced allergen risks. Twenty-five additional breeding selections have been propagated for regional planting in smaller-scale grower trials following intensive multi-year selection in UCD breeding evaluation blocks at Winters, California. In addition to the range of tree architectures currently being evaluated in grower and Regional Variety Trials, novel tree architectures including columnar-types and long-spur (dard) bearing habits, possessing self-fruitfulness as well as good kernel quality and productivity are currently being assessed for value in more futuristic, high density, mechanized catch-frame harvest strategies. Despite cutbacks in University support, the breeding program continues to successfully generate the large populations from controlled crosses necessary to further combine novel traits such as self-fruitfulness with the range of tree, nut and kernel qualities required for commercial success. At the same time, efforts are continuing to maintain and even enrich the current breeding germplasm in order to further capture and evaluate additional new traits with potential for solving California production and processing problems. Changes in orchard land and water quality and subsequent management and cultural practices have led to the need for a new generation of rootstocks with improved disease and environmental stress resistance. Responding to this need, a number of public and private efforts have been initiated to develop and test new rootstocks for California tree crops. Germplasm derived from interspecies hybrids is often pursued to attain the greatest range of vigor and desirable horticultural traits. However, the development of such exotic germplasm is often difficult and time-consuming and, as has been recently shown with the UCB1 pistachio hybrid rootstock, the genetic, genomic and cultural interactions can be complex and unpredictable. As part of our long-term UCD almond and peach variety development programs, breeding lines have been and continue to be developed combining almond, peach and plum as well as with an extensive diversity within related Prunus species. Early selections within this germplasm have demonstrated traits which appear desirable for rootstocks, including possible drought, nutrient, insect and disease tolerance, and modified tree size/structure. This germplasm is being made available to interested public and private rootstock development programs as clonal as well as segregating seedling populations to facilitate and accelerate comprehensive testing. Over 2,000 genetically diverse genotypes derived from this diverse UCD germplasm including peach (P. persica), almond (P. dulcis), P. mira, P. davidiana, P. scoparia, P. tangutica, P. webbii, P argentea, P. orthosepala, and P. bucharica (see Figure 2) have been transferred in 2017 for evaluation in several public and private programs for resistance to drought, salinity, boron toxicity, as well as diseases and pests (Table 1). The development of effective molecular markers for nematode and disease resistance allows improved selection and so breeding efficiency. However, the number and diversity of rootstock characteristics needed for commercial success, require the development of breeding populations well beyond those manageable through traditional molecular marker assisted breeding alone. Consequently, an aggressive breeding strategy has been developed which allows efficient concurrent assessment of both hybrid rootstock candidates as well as progeny derived from these hybrids for subsequent inheritance and molecular marker studies. The most promising species, as well as individual genotypes within species are then selected (based on disease resistance, molecular marker assessment as well as overall field performance) for a subsequent round of hybridization and testing . By Dec., 2018, over 300 additional species-hybrids and over 1,400 segregating F2 seed were recovered from controlled pollinations. All processes, including formal data compilation/analysis, legal paperwork, University procedures and virus-tested, foundation tree establishment at Foundation Plant Services (FPS) have been completed for the patenting and release of the UCD peach variety Vilmos (USPP29623P3) as an alternative to the Early season Andross variety. The UCD processing peach variety Kader has also been recently formally released (USPP26871) as a replacement variety for the Extra-Early `Dixon-gap'. The Ultra-Early selection Ogawa is being proposed for released in 2019 as an unpatented UCD variety, with UCD selection Early#6 in the final stages of regional trials prior to formal release procedures. New breeding blocks have been established at the UCD Wolfskill Experimental Orchards (WEO) to supplement earlier breeding blocks established at Davis as well as to provide alternative crossing environments when confronted with local inclement weather patterns such as frost, localized low-chilling, etc. New plantings of breeding progeny for 2018 were consistent with the earlier years but below expanded 2018 targets (Table 1). Over 30,000 controlled hybridizations, among 28 different parental combinations were completed in 2018, though frost damage in some of the UCD crossing plots reduced seed set to less than 7,000 viable seed. Of these over 2,000 were field planted with an additional 3,000 seed from 2018 and earlier harvest being retained for 2019 planting when new land would be opened-up.
Publications
- Type:
Books
Status:
Published
Year Published:
2017
Citation:
Socias I Company and T. Gradziel {Editors} (2017) Almonds: Botany, Production and Uses. CABI Press, Boston 494 pgs.
- Type:
Book Chapters
Status:
Published
Year Published:
2017
Citation:
Gradziel, TM. History of Cultivation. In: Socias I Company and T. Gradziel {Editors} (2017) Almonds: Botany, Production and Uses. CABI Press, Boston 494 pgs.
- Type:
Book Chapters
Status:
Published
Year Published:
2017
Citation:
Gradziel, TM , Robert Curtis and Rafel Socias i Company. Production and Growing Regions. In: Socias I Company and T. Gradziel {Editors} (2017) Almonds: Botany, Production and Uses. CABI Press, Boston 494 pgs.
- Type:
Book Chapters
Status:
Published
Year Published:
2017
Citation:
Batlle, I., Federico Dicenta, Rafel Socias i Company, Thomas M. Gradziel, Michelle Wirthensohn, Henri Duval and Francisco J. Vargas. Classical Genetics and Breeding. In: Socias I Company and T. Gradziel {Editors} (2017) Almonds: Botany, Production and Uses. CABI Press, Boston 494 pgs
|
Progress 10/01/16 to 09/30/17
Outputs
Target Audience:Research scientists, crop advisors, growers, processors, consultants, consumers. Changes/Problems:Reduction in Hatch support. What opportunities for training and professional development has the project provided?Trained 1 PhD and 1 MS students the last year How have the results been disseminated to communities of interest?Multiple publications, multiple professional presentations and multiple consumer/grower presentations. What do you plan to do during the next reporting period to accomplish the goals?Continue with current strategy as presented in 2014, 5-year plan
Impacts
What was accomplished under these goals?
The release of the Vilmos processing peach ripening with Andross, along with the previous release of the the Kader processing peach, ripening in the Dixon gap, and Vilmos, andv the accelerated regional testing of Ultra-Early-1 and Early-6 represent the pivot of UCD Processing Peach Breeding Program priorities to the Extra-Early and Early harvest seasons. The early California processing peach industry was dominated by Late and Extra-Late varieties. Harvest extension into the Early and Extra-Early seasons utilize the traditionally available germplasm which led to the development of earlier varieties but also inherent limitations. A major and expected limitation was the decrease in fruit size as well as sugar content, and so tree productivity, with increasingly earlier harvest dates. An unexpected limitation was the high vulnerability of this traditional germplasm to higher levels of red pit staining and pit fragmentation for varieties ripening in the Dixon to Andross harvest season. The early efforts of this breeding program identified vulnerabilities in the traditional germplasm as a major basis for these limitations. A long-term effort ensued to bring new and genetically diverse germplasm into the breeding program, and incorporate this new genetic material into the breeding program through a series of recurrent backcrosses, hybridizations and self-pollinations, so that it was made better adapted to California production and processing conditions. Kader, Vilmos and Early-6 represent the first releases utilizing this nontraditional germplasm. A number of next-generation genotypes, the results of further refinement and selection for regional-adaptability, fruit quality and productivity, disease/stress resistance, and reduced grower production cost, have been selected for the next round of regional testing (see 2017 Regional Testing Annual Report). Ongoing breeding efforts towards development of 3rd generation varieties target recombination among these diverse yet refined germplasm sources in order to further combine genes exhibiting desirable performance in targeted traits. Because of the range of novel germplasm incorporated into current breeding material, appropriate recombination of this germplasm may allow progress beyond the expected additive effects for genes controlling maturity, firmness, etc. to achieve synergistic effects well beyond the performance observed in individual parents. Examples of such synergism currently under genetic study include high quality and productive varieties ripening within the Dixon gap showing very low incidence of red-pit-staining and associated pit fragmentation, and varieties able to hold fruit on the tree for a week or more without appreciable loss in processing quality. Knowledge required for the appropriate manipulation of these novel and complex traits requires detailed genetic analysis and thus are the basis of the current RosBreed-2 molecular and phenotypic analysis. In the 2017 season, the number of UCD genotypes accepted by the RosBreed genome Center for molecular characterization is over 1,000 individual genotypes. Phenotyping of all seedling trees (primarily from the 2010 and 2011 seedling evaluation blocks) continued in 2017 with evaluation of field performance for all genotypes, as well as field data four fruit brown rot susceptibility. [The goal is to collect complete brown rot and fruit quality information for all 1200 individuals over the 4 years of the project]. Based on genomic, genetic and phenotypic information developed from these ongoing breeding efforts, including the RosBreed-1 molecular nalysis (see References), over 40 parents were selected in 2017 for further crosses. A total of over 20,000 controlled hybridization were achieved resulting in over eight thousand fruit with over 1,000 seedlings planted in the fall of 2017. Following initial seedling selection (rogueing-out of inferior seedlings), approximately 4,000 seedlings are currently being advanced to 2018 spring field-planting. Over 4,000 fruit were recovered from targeted self-pollinations, with 3,000 being prepared for spring 2018 planting with the remainder held in reserve. The California almond industry is in a historic period of transformation driven by increased Central Valley acreage along with increasing environmental and market requirements, reductions in resources such as water, agrochemicals, and natural pollinators, as well as the uncertainties of a changing climate. While almond represents a diverse and highly adaptable species, commercial production in California is dependent almost entirely on the variety Nonpareil and a relatively few closely-related pollenizers, most of which have Nonpareil and Mission as direct parents. A long-term emphasis of the UCD almond breeding program has been the identification and incorporation of new and diverse germplasm. Genetic solutions to emerging production challenges are now becoming available from this improved germplasm, including regionally-adapted selections expressing high productivity, self-fruitfulness, and increased insect, disease and environmental stress resistance. Improved breeding lines also offer opportunities to expand market demand by optimizing phytonutrients in new cultivars, such as the high heart-friendly oleic acid content in the recently released Sweetheart variety, while minimizing potential health and marketing risks including aflatoxins, allergens and salmonella. This past year saw the second year of extensive field data collection for a new set of Regional Variety Trials (RVT) which includes a large number of UCD selections derived from genetically diverse pedigrees. The diversity has been introduced to allow the capture of the greatest genetic contributions to orchard yield, kernel quality and disease/pest/stress resistance in future California orchards. Ongoing studies in the newly established as well as previous RVT's are demonstrating significant opportunities for improving tree architecture and cropping efficiency, disease and stress resistance, kernel quality and tree and orchard productivity. Following long-term RVT and grower testing in all major California production regions, the UCD breeding program has recently released the Kester almond variety. This variety is the result of a cross between Tardy-Nonpareil (a late-flowering mutation of Nonpareil) and Arbuckle. Kester is fully cross-compatible with Nonpareil as well as other late-bloom pollenizers and blooms approximately 4 days after Nonpareil and so is less vulnerable to damage by early spring frosts. Kester kernels are similar to Nonpareil but with well-sealed, worm resistant shells. The variety produces low frequencies of double kernels and twin embryos. Harvest is 4 to 7 days after Nonpareil. Trees are upright to spreading and moderately vigorous, being about 80% of Nonpareil size at maturity. The Kester variety has consistently been among the most productive of all evaluated selections and varieties in over 16 years of Regional Variety Trials. Long-term regional testing also showed no Noninfectious Bud-failure or pronounced susceptibility to commercially important diseases and pests. This variety, as well as the Kader and Vilmos varieties, are now available under license from the Regents of the University of California. Budwood of the new variety has been subjected to the virus indexing program of Foundation Plant Service (FPS), University of California at Davis, CA. All indices have proven to be negative for viruses and Foundation trees of this genotype are presently being maintained at FPS.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Fresnedo-Ram�rez, J., Chan, H. M., Parfitt, D. E., Crisosto, C. H., & Gradziel, T. M. 2017. Genome-wide DNA-(de)methylation is associated with Noninfectious Bud-failure exhibition in Almond (Prunus dulcis [Mill.] D.A.Webb). Scientific Reports, 7. doi:10.1038/srep42686
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Fresnedo-Ramirez, J., Crisosto, C. H., Gradziel, T. M. and Famula, T. R. Xiloyannis, C., Inglese, P. and Montanaro, G. 2016 Pedigree correction and estimation of breeding values for peach genetic improvement. Acta Horticulturae no. 1084: 249-256.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Changqi Liu. : "Comparison of Laboratory-Developed and Commercial Monoclonal Antibody-Based Sandwich Enzyme-Linked Immunosorbent Assays for Almond (Prunus dulcis) Detection and Quantification". 2017. JFDS-2017-0264.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Jonathan Fresnedo-Ram�rez, Thomas R. Famula and Thomas M. Gradziel. 2017. Application of a Bayesian ordinal animal model for the estimation of breeding values for the resistance to Monilinia fruticola (G.Winter) Honey in progenies of peach [Prunus persica (L.) Batsch]. Breeding Science Preview doi:10.1270/jsbbs.16027
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Mart�nez-G�mez P, Prudencio AS, Gradziel TM, Dicenta F. 2017. The delay of flowering time in almond: a review of the combined effect of adaptation, mutation and breeding. Euphytica 213 (8): 197. DOI 10.1007/s10681-017-1974-5
|
Progress 10/01/15 to 09/30/16
Outputs
Target Audience:Research scientists, growers, processors, consultants, consumers. Changes/Problems:Reduction in Hatch support. What opportunities for training and professional development has the project provided?Trained two PhD and 2 MS students the last year How have the results been disseminated to communities of interest?Multiple publications, multiple professional presentations and multiple consumer/grower presentations. What do you plan to do during the next reporting period to accomplish the goals?Continue with current strategy as presented in 2014, 5-year plan
Impacts
What was accomplished under these goals?
The release of Kader Processing peach, ripening in the Dixon gap, and Vilmos, ripening with Andross, and the accelerated regional testing of Ultra-Early-1 and Early-6 represent the pivot of UCD Processing Peach Breeding Program priorities to the Extra-Early and Early harvest seasons. (See detailed descriptions of these items in the 2015 annual reports as well as the 2016 Regional Testing Annual Report). The early California processing peach industry was dominated by Late and Extra-Late varieties. Harvest extension into the Early and Extra-Early seasons utilize the traditionally available germplasm which led to the development of earlier varieties but also inherent limitations. A major and expected limitation was the decrease in fruit size as well as sugar content, and so tree productivity, with increasingly earlier harvest dates. An unexpected limitation was the high vulnerability of this traditional germplasm to higher levels of red pit staining and pit fragmentation for varieties ripening in the Dixon to Andross harvest season. The early efforts of this breeding program identified vulnerabilities in the traditional germplasm as a major basis for these limitations. A long-term effort ensued to bring new and genetically diverse germplasm into the breeding program, and incorporate this new genetic material into the breeding program through a series of recurrent backcrosses, hybridizations and self-pollinations, so that it was made better adapted to California production and processing conditions. Kader, Vilmos and Early-6 represent the first releases utilizing this nontraditional germplasm. A number of next-generation genotypes, the results of further refinement and selection for regional-adaptability, fruit quality and productivity, disease/stress resistance, and reduced grower production cost, have been selected for the next round of regional testing (see 2016 Regional Testing Annual Report). Ongoing breeding efforts towards development of 3rd generation varieties target recombination among these diverse yet refined germplasm sources in order to further combine genes exhibiting desirable performance in targeted traits. Because of the range of novel germplasm incorporated into current breeding material, appropriate recombination of this germplasm may allow progress beyond the expected additive effects for genes controlling maturity, firmness, etc. to achieve synergistic effects well beyond the performance observed in individual parents. Examples of such synergism currently under genetic study include high quality and productive varieties ripening within the Dixon gap showing very low incidence of red-pit-staining and associated pit fragmentation, and varieties able to hold fruit on the tree for a week or more without appreciable loss in processing quality. Knowledge required for the appropriate manipulation of these novel and complex traits requires detailed genetic analysis and thus are the basis of the current RosBreed-2 molecular and phenotypic analysis. In the 2016 season, the number of UCD genotypes accepted by the RosBreed genome Center for molecular characterization has increased to over 1,200 individual genotypes. Phenotyping of all 1200 seedling trees (primarily from the 2010 and 2011 seedling evaluation blocks) continued in 2016 with evaluation of field performance for all genotypes, as well as detailed information on fruit brown rot susceptibility (in collaboration with the Bostock lab) and fruit soluble-solids and acidity (in collaboration with the Crisosto Post-harvest lab) for a subset of over 270 genotypes. [The goal is to collect complete brown rot and fruit quality information for all 1200 individuals over the 4 years of the project]. Based on genomic, genetic and phenotypic information developed from these ongoing breeding efforts, including the RosBreed-1 molecular nalysis (see Fresnedo, Techakanon, and Agaki References), over 80 parents were selected in 2016 for further crosses. A total of 27,521 controlled hybridization were achieved resulting in 7,437 fruit with over 5,000 seedlings planted in the fall of 2016. Following initial seedling selection (rogueing-out of inferior seedlings), approximately 3,000 seedlings are currently being advanced to 2017 spring field-planting. Over 5,000 fruit were recovered from targeted self-pollinations, with 2,000 being prepared for spring 2017 planting with the remainder held in reserve. The California alond industry is in a historic period of transformation driven by increased Central Valley acreage along with increasing environmental and market requirements, reductions in resources such as water, agrochemicals, and natural pollinators, as well as the uncertainties of a changing climate. While almond represents a diverse and highly adaptable species, commercial production in California is dependent almost entirely on the variety Nonpareil and a relatively few closely-related pollenizers, most of which have Nonpareil and Mission as direct parents. A long-term emphasis of the UCD almond breeding program has been the identification and incorporation of new and diverse germplasm. Genetic solutions to emerging production challenges are now becoming available from this improved germplasm, including regionally-adapted selections expressing high productivity, self-fruitfulness, and increased insect, disease and environmental stress resistance. Improved breeding lines also offer opportunities to expand market demand by optimizing phytonutrients in new cultivars, such as the high heart-friendly oleic acid content in the recently released Sweetheart variety (see Reference 1), while minimizing potential health and marketing risks including aflatoxins, allergens and salmonella. This past year saw the establishment of a new set of Regional Variety Trials (RVT) which includes a large number of UCD selections derived from genetically diverse pedigrees. The diversity has been introduced to allow the capture of the greatest genetic contributions to orchard yield, kernel quality and disease/pest/stress resistance in future California orchards. Ongoing studies in the newly established as well as previous RVT's are demonstrating significant opportunities for improving disease and stress resistance, kernel quality and tree and orchard productivity. Following long-term RVT and grower testing in all major California production regions, the UCD breeding program has released the Kester almond variety. This variety is the result of a cross between Tardy-Nonpareil (a late-flowering mutation of Nonpareil) and Arbuckle. Kester is fully cross-compatible with Nonpareil as well as other late-bloom pollenizers and blooms approximately 4 days after Nonpareil and so is less vulnerable to damage by early spring frosts. Kester kernels are similar to Nonpareil but with well-sealed, worm resistant shells. The variety produces low frequencies of double kernels and twin embryos. Harvest is 4 to 7 days after Nonpareil. Trees are upright to spreading and moderately vigorous, being about 80% of Nonpareil size at maturity. The Kester variety has consistently been among the most productive of all evaluated selections and varieties in over 16 years of Regional Variety Trials. Long-term regional testing also showed no Noninfectious Bud-failure or pronounced susceptibility to commercially important diseases and pests. This variety is now available under license from the Regents of the University of California. Budwood of the new variety has been subjected to the virus indexing program of Foundation Plant Service (FPS), University of California at Davis, CA. All indices have proven to be negative for viruses and Foundation trees of this genotype are presently being maintained at FPS under the designation `Kester' or the UCD Breeding designation `Kester 2-19E'.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Fresnedo-Ramirez, J., Frett, T. J., Sandefur, P. J., Salgado-Rojas, A., Clark, J. R., Gasic, K., Peace, C. P., Anderson, N., Hartmann, T.P., Byrne, D.H., Bink, M., Van de Weg, E., Crisosto, C. and Gradziel, T.M. 2016. QTL mapping and breeding value estimation through pedigree-based analysis of fruit size and weight in four diverse peach breeding programs. Tree Genetics and Genomes 12 (2): 25.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Techakanon, Chukwan; Gradziel, Thomas; Zhang, Lu; Barrett, Diane. 2016. The Impact of Maturity Stage on Cell Membrane Integrity and Enzymatic Browning Reactions in High Pressure Processed Peaches (Prunus persica). Journal of Agricultural and Food Chemistry DOI: 10.1021/acs.jafc.6b02252.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Akagi, T, Hanada,T, Yaegaki, H, Gradziel, T,and Ryutaro Tao, R. 2016. Genome-wide view of genetic diversity reveals paths of selection and cultivar differentiation in peach domestication. DNA Research,1 -12. DOI: 10.1093/dnares/dsw014.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Techakanon, Chukwan; Gradziel, Thomas; Zhang, Lu; Barrett, Diane. 2016. Effects of Peach Cultivar on Enzymatic Browning Following Cell Damage from High Pressure Processing. Journal of Ag. and Food Chemistry, DOI: 10.1021/acs.jafc.6b01879
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Nassar , N.M.A. , N. N. Bomfim Fernandes, , D. Y. Hashimoto Freitas. and T. M. Gradziel. 2016. Interspecific Periclinal Chimeras as a Strategy for Cultivar Development. In J. Janick (ed.) Plant Breeding Reviews. 40:235-263. ISBN: 978-1-119-27968-6.
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Progress 10/01/14 to 09/30/15
Outputs
Target Audience:Research scientists, growers, processors, consultants, consumers. Changes/Problems:Reduction in Hatch support. What opportunities for training and professional development has the project provided?Trained one postdoc, and two PhD students the last year How have the results been disseminated to communities of interest?Multiple publications, multiple professional presentations and multiple consumer/grower presentations. What do you plan to do during the next reporting period to accomplish the goals?Continue with strategy presented in previous (2014) 5 year final report
Impacts
What was accomplished under these goals?
Over 8,000 seed from controlled hybridizations and subsequent cycles of self-pollinations were generated in 2015, with over 3,000 subsequent seedlings planted to Davis and Winters field evaluation plots (Table 1). As in 2014, conditions for controlled-crosses were difficult because low winter chill caused a more extended bloom time for many peach selections resulting in fewer flowers available controlled hybridization at any particular day. Resulting fruit set was also lower than normal, possibly due to the warmer weather at bloom. To compensate for these conditions, over 20,000 controlled hybridizations were made targeting replacements for the Dixon-Andross and Halford-Corona maturity periods as well as pre-Loadel maturity. Long-term climate predictions suggesting a continuing and perhaps accelerating loss of winter chill/fog conditions have led to a renewed emphasis on identifying selections tolerant to winter chill vagaries, as well as the development of hybridization methods allowing higher fruit-sets under these more challenging environments. Good fruit quality was achieved for both seedling and advanced selection evaluation blocks despite the very high number of seedlings (~30,000) currently in full production. Key to the consistent recovery of good fruit quality was the implementation of previously developed field practices such as properly applied mechanical tree hedging and flower thinning to facilitate uniform cropping with low labor inputs.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Mengna Su, Mahesh Venkatachalam, Thomas M. Gradziel, Changqi Liu,Ying Zhang, Kenneth H. Roux, Shridhar K. Sathe. 2015. Application of mouse monoclonal antibody (mAb) 4C10-based enzyme-linked immunosorbent assay (ELISA) for amandin detection in almond (Prunus dulcis L.) genotypes and hybridsLWT - Food Science and Technology 60 (2015) 535e543.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Fresnedo-Ram�rez J, Bink MCAM, van de Weg E, Famula TR, Crisosto CH, Frett TJ, Gasic K, Peace CP, Gradziel TM (2015). QTL mapping of pomological traits in peach and related species breeding germplasm. Molecular Breeding 35:166. Weblink: http://link.springer.com/article/10.1007%2Fs11032-015-0357-7.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Minas IS, Font i Forcada C, Dangl GS, Gradziel TM, Dandekar AM, Crisosto CH (2015). Discovery of non-climacteric and suppressed climacteric bud sport mutations originating from a climacteric Japanese plum cultivar (Prunus salicina Lindl.). Frontiers in Plant Science 6:316.
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