Progress 10/23/15 to 09/30/20
Outputs
Target Audience:Target Audience: The primary target audience is comprised of cooperators in a national cotton testing program known as the "Regional Breeders Testing Network" or more simply the "RBTN". The RBTN group represents cotton breeders, geneticists, agronomists, pathologists and extension specialists from Land Grant Universities and USDA-ARS. Although members of this audience are restricted primarily to scientists from the public sector, a couple of members of the RBTN group are from the private sector, including a commercial cotton seed company and Cotton Incorporated (a quasi-private non-profit cotton commodity organization). Target audiences also included attendees of the annual Beltwide Cotton Conferences and graduate students (MS & PhD) working under the direction of the PI. Efforts: Directed individual study course entitled "Marker Assisted Selection in Cotton Seed Production", based upon a component of breeding for reniform resistant, was developed to provide graduate level credit. Changes/Problems:Marker assisted selection within several different populations segregating for reniform resistance resulted in the selection and testing of 55 reniform resistant breeding lines. This first generation of resistant breeding lines were selected primarily on the presence of QTLs for resistance, not lint yield and fiber quality. Resistant breeding lines were developed, but selection for resistance must be combined with selection for yield potential. Therefore, individual marker assisted plant selections were made within the resistant breeding lines, and then followed up by progeny row testing. Progeny row testing required marking testing a subset of plants within each progeny row to confirm resistance and remove any susceptible plants. Marker confirmed plants were harvested by hand prior to machine harvest of the row. Progeny rows will be evaluated for yield, lint percent and fiber quality. This change will provide opportunity to select progeny rows with the highest yield potential and fiber quality before replicated yield testing. What opportunities for training and professional development has the project provided?Project has served as a research problem for two graduate students leading to Master level degrees. Project served to provide both students their first opportunity for presenting results at a professional meeting. How have the results been disseminated to communities of interest?Research related results have been presented at the Beltwide Cotton Conferences, the Mississippi Academy of Sciences (graduate student poster), and a local graduate student competition. Research related results have also been published in a MS thesis and one journal article. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
1) Combine reniform nematode resistance trait from recent G. barbadense derived germplasm lines with yield and fiber quality traits from good performing breeding lines. Project initially resulted in the development of 73 breeding lines, comprised of 55 reniform resistant lines and 18 root-knot resistant lines, developed from populations segregating for nematode resistance. Lines were developed using marker assisted selection (MAS) to identify plants with gene(s) with resistance. In 2017 and 2018, performance of resistant breeding lines were compared to the resistant donor parent and susceptible commercial check cultivars in replicated yield trials. Most of the reniform resistant breeding lines exhibited significant improvements in yield when compared to the donor parent. However, when compared to the yield of susceptible commercial check cultivars, all resistant breeding lines produced a significantly lower yield. As a result, a decision was made to discontinue any further testing for this initial population of 73 breeding lines. Based on an expectation that considerable genetic variation remained, it was decided to further exploit this variation in an attempt to improve lint yield. In 2019, MAS within previously developed reniform resistant breeding lines resulted in selection and harvest of 236 individual plants possessing the QTL for reniform resistance. Plant selections with a low lint percentage were discarded and the remaining 99 plants were planted to progeny rows in 2020, the final year of the project. Leaf samples were collected from a subset of plants within each progeny row for marker analysis. Marker testing will be used to characterize resistance and homogeneity for resistance within each progeny row. Although it was anticipated we would conduct marker testing and have results prior to harvest, the USDA-ARS Genomics and Bioinformatics Research Unit (GBRU) in Stoneville, MS, was closed due to COVID-19. Therefore, samples were placed in a -80C freezer and will be removed for marker testing in the spring of 2021. Each plant that was sampled for marker testing was harvested as an individual plant and will be kept in storage until marker testing can proceed. Leaf samples stored in a -80C freezer, along with stored seed of the corresponding plant, will serve as the beginning of a new project in 2021. 2) Identify reniform resistant breeding lines with improvements in yield and fiber quality traits when compared to current available reniform resistant lines. Analysis of replicated 2017 and 2018 yield trials revealed that many of the selected reniform resistant breeding lines showed a marked improvement of yield when compared to the reniform resistant check cultivar BARBREN-713 (resistance donor parent). Fiber quality was also improved with several of the lines approaching the quality of the susceptible commercial check cultivars. However, when compared to the susceptible commercial check cultivars, lint yield of the resistant breeding lines was significantly lower. Although this objective was not achieved, it did provide evidence indicating that G. barbadense derived resistance can be combined with yield that is competitive with susceptible commercial cultivars. Based on the above observations, a decision was made to conduct another round of marker assisted selection within previously selected lines. This was conducted in 2019 followed by progeny row testing in 2020 to identify lines with high yield potential. 3) Quantify reniform nematode resistance in breeding lines identified with improved agronomic performance. No breeding lines were identified that performed equal to the susceptible commercial check cultivars. Therefore, selected breeding lines were not phenotyped for resistance to reniform. Rather than quantify resistance, breeding efforts will focus on improving yield before quantifying resistance. 4) Evaluate newly developed reniform resistant breeding lines in multiple environments to determine competitiveness with high yielding reniform susceptible breeding lines and varieties. Not completed. Yield testing was terminated based upon results of testing in two environments. Objectives one and two are currently being repeated in search of higher yielding resistant genotypes. 5) Release reniform resistant breeding lines with improved agronomics traits (yield and or fiber quality traits). Not completed. This objective will be addressed pending the development of reniform resistant breeding line(s) with competitive yield and fiber performance.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Gaudin, A.G., Wallace, T.P., Scheffler, J.A., Stetina, S.R., Wubben, M. 2020. Effects of combining Renlon with Renbarb1 and Renbarb2 on resistance of cotton (Gossypium hirsutum L.) to reniform nematode (Rotylenchulus reniformis Linford and Oliveira). Euphytica. 216:67. https://doi.org/10.1007/s10681-020-02580-3.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2020
Citation:
Celik, B., Wallace, T. P., Scheffler, J. A., Stetina, S. R. (2020). Effect of Renlon, Renbarb1, and Renbarb2 Gene Combinations on Resistance to Reniform Nematode and Agronomic Traits in Upland Cotton. Mississippi Academy of Sciences, Vol 65, No. 1, Abstract P1.07.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Gaudin, A., Wallace, T., Stetina, S.R., Scheffler, J.A. 2017. A Study on the Effects of Combining Genes from LONREN and BARBREN on Reniform Resistance. National Cotton Council Beltwide Cotton Conference. 2017 Beltwide Cotton Conferences, Dallas, TX, January 4-6, 2017; 457.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Wallace, T., Gaudin, A., Stetina, S.R., Scheffler, J.A. 2017. Progress in Development of Reniform Resistant Germplasm Developed from BARBREN-713. National Cotton Council Beltwide Cotton Conference. 2017 Beltwide Cotton Conferences, Dallas, TX, January 4-6, 2017; 518.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2017
Citation:
Gaudin, A.G. 2017. Effects of combining Renlon with Renbarb1 and Renbarb2 genes on resistance of cotton (Gossypium hirsutum) to reniform nematode (Rotylenchulus reniformis) Masters Thesis, December 2017, Mississippi State University. https://hdl.handle.net/11668/19686.
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Progress 10/01/18 to 09/30/19
Outputs
Target Audience:Cotton Incorporated, public cotton breeders, undergraduate and graduate level students Changes/Problems:Reniform resistant breeding lines developed for this project were evaluated for yield and fiber quality. When performance of the resistant breeding lines was compared to commercial cotton "check" cultivars, it became apparent that the resistant breeding lines lacked the yield potential needed to compete with commercial cultivars. To be useful to cotton breeding programs, the yield potential of reniform resistant breeding lines must be competitive with commercial cultivars. To address this issue, marker assisted selection of productive plants within each breeding line was initiated in 2019 in an effort to identify and develop resistant lines with improved yield potential. Selected plants will be evaluated in progeny rows in 2020, and the best performer selections will be advanced for replicated yield and fiber testing. What opportunities for training and professional development has the project provided?Research to investigate the effect of combining different genes for resistance to reniform nematode has served as a graduate student research project for a MS student and a PhD student. Research results have been presented at professional meetings and one article has been accepted for publication in a major journal. How have the results been disseminated to communities of interest?Research results concerning the effects of combining different genes for resistance to reniform nematode have recently been accepted for publication in Euphytica. Graduate student proposed research to examine the effect of different reniform resistant gene combinations on stunting under field conditions was presented in poster form at the 2019 summer symposium of the Mississippi Academy of Sciences. What do you plan to do during the next reporting period to accomplish the goals?The primary goal of this project was to utilize recently developed reniform resistant germplasm in a breeding program to develop cotton with improved yield and fiber quality to meet industry demands. Resistant breeding lines were developed and evaluated for yield and fiber quality over several years. Yield and fiber quality performance of resistant lines was not competitive with the commercial check cultivars. Based on these results, a decision was made in 2019 to seek improvements further improvements in yield and fiber quality. Marker assisted selection (MAS) within each breeding line for individual plants with good boll production was conducted in 2019 in an effort to identify and develop additional resistant breeding lines with improved yield and fiber quality. Approximately 125 plants from MAS will be planted to progeny rows and evaluated for yield and fiber quality during the next reporting period. Performance of selected plants in progeny rows will be compared to several commercial "check" cultivars. Progeny rows will be selected for advancement if yield and quality performance is equal to or greater than the performance of check cultivars.
Impacts
What was accomplished under these goals?
1. Combine reniform nematode resistance trait from recent G. barbadense derived germplasm lines with yield and fiber quality traits from good performing breeding lines. Three populations (F3F7, F4F8, F5F9) representing 55 reniform resistant breeding lines were evaluated in replicated yield trials in 2017, 2018 and 2019. Although many of the lines had a higher yield potential than resistant parental germplasm BARBREN-713, lint yields have not been competitive with conventional commercial check cultivars. Furthermore, testing to confirm the presence of molecular markers for reniform resistance was not available during the last two generations of seed production. Therefore, during the 2019 growing season, MAS (re-selection) within breeding lines was employed in an effort to select plants with improved yield potential and fiber quality traits. 2. Identify reniform resistant breeding lines with improvements in yield and fiber quality traits when compared to current available reniform resistant lines. Approximately 150 individual plants were selected (MAS) from within three populations of reniform resistant breeding lines in an effort to identify and develop additional new lines with improved yield potential and fiber quality. The total number of plant selections will be reduced based upon lint percentage and fiber quality (gin data) prior to evaluation in progeny rows for yield and fiber quality performance in 2020. 3. Quantify reniform nematode resistance in breeding lines identified with improved agronomic performance. Research to evaluate the effect of combining two widely different sources of resistant to reniform nematode on resistance and plant growth continues to serve as a graduate student research project. A full-sib family of inbred lines have been developed to represent all possible combinations of Renlon and Renbarb genes for resistance to reniform nematode. Both genes provide for a high level of resistance, but the Renlon gene, which has been associated with significant stunting, is no longer used in breeding programs as a source of resistance. The current research is aimed at determining if stunting can be eliminated or reduced when Renlon is combined with Renbarb, and thereby provide a new, multi-genic source of resistance to reniform. Inbred lines were grown for seed increase and marker confirmation in 2019. Lines will be evaluated in a reniform infested field soil in 2020 to quantify resistance and stunting. 4. Evaluate newly developed reniform resistant breeding lines in multiple environments to determine competitiveness with high yielding reniform susceptible breeding lines and varieties. Newly developed reniform resistant breeding lines were evaluated in a replicated yield trial at a single environment for three years. An analysis of lint yield over years revealed that most reniform resistant breeding lines produced a significantly lower lint yield when compared to conventional commercial cotton cultivars. In an attempt to improve the yield potential of reniform resistant breeding lines, marker assisted re-selection within the better breeding lines was carried out during 2019. Selected plants will be evaluated as progeny rows in 2020. 5. Release reniform resistant breeding lines with improved agronomics traits (yield and or fiber quality traits. Nothing to report.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2019
Citation:
Gaudin AG, Wallace TP, Scheffler JA, Stetina SR, Wubben MJ. Effects of combining Renlon with Renbarb1 and Renbarb2 on resistance of cotton (Gossypium hirsutum L.) to reniform nematode (Rotylenchulus reniformis Linford and Oliveria). Euphytica (accepted Dec 2019)
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2019
Citation:
Celik B., Wallace TP, Scheffler JA, Stetina SR. 2019. Effect of Renlon, Renbarb1, and Renbarb2 Gene Combinations on Resistance to Reniform Nematode and Agronomic Traits in Upland Cotton. Mississippi Academy of Sciences Summer Symposium. Poster Presentation, July 11, 2019, Bost Extension Center, Mississippi State, MS.
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Progress 10/01/17 to 09/30/18
Outputs
Target Audience:Cotton Incorporated, public cotton breeders, undergraduate and graduate level students. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Training Activities - A component of this project provided the opportunity for a student to conduct research leading to the successful completion of a master's level graduate degree in the fall of 2017. A research project investigating the effect of different combinations of genes for resistance to reniform nematode required training in planting, growing and maintaining research field plots, plant growth characteristics, and the use of molecular markers. How have the results been disseminated to communities of interest?Results of all breeding related activities were reported in Cotton Incorporated quarterly and annual reports . What do you plan to do during the next reporting period to accomplish the goals?Planned marker testing, used to confirm reniform resistance, could not be conducted in 2018. As a result, the 2018 growing season was largely lost in terms in identifying and confirming reniform resistance in breeding lines. This was the second year for which marker testing, a key component in the development of reniform resistant breeding lines, could not be conducted. Breeding efforts in 2019 will concentrate on marker selection to identify lines homogeneous for genes conferring resistance to reniform.
Impacts
What was accomplished under these goals?
Nematodes are microscopic worm-like parasitic organisms that feed on roots of crop plants resulting in stunting and a loss in production. The reniform is an important pest of upland cotton in Mississippi and throughout the Southeastern US. Although reniform nematodes are one of the most important pests of cotton in Mississippi, all commercial varieties of cotton are considered to be susceptible to this pest. In 2014, damage from reniform nematode resulted in the loss of an estimated 58,000 bales of cotton in Mississippi. The use of nematicides can be cost prohibitive while cultural control methods, such as planting an alternate crop, may not be a viable alternative. Plant breeding efforts in the current project are directed at developing reniform nematode resistant cotton germplasm lines suitable for use in the development of commercial cotton varieties. The use of molecular markers greatly simplifies identification of plants resistant to reniform nematode based DNA extracted from leaf tissue. Development and planting of host plant resistant cotton varieties would be the most economical and successful approach to reducing losses attributed to reniform nematode. 1. Combine reniform nematode resistance trait from recent G. barbadense derived germplasm lines with yield and fiber quality traits from good performing breeding lines. Three populations of reniform resistant breeding lines (F5, F6, and F7), were previously developed through marker assisted selection among populations segregating for resistance. Each year, plants within each breeding line are evaluated with markers to ensure only those plants possessing genes for resistance are advanced to the next generation. However, due to unavoidable circumstances during the 2018 growing season, marker testing could not be conducted. Therefore, efforts in 2018 concentrated on evaluating breeding lines for yield and fiber quality performance. Each breeding line was also planted to a single row plot to produce seed for evaluations in 2019. 2. Identify reniform resistant breeding lines with improvements in yield and fiber quality traits when compared to current available reniform resistant lines. Each population (F5, F6, and F7) of reniform resistant breeding lines were evaluated for yield and fiber quality performance in a replicated trial. Each trial included several commercial check (susceptible check) varieties as well as a reniform resistance breeding line (resistant check) for comparing performance of reniform resistant lines with susceptible lines. Trials have been harvested but results for yield and fiber performance is currently pending data analyses. 3. Quantify reniform nematode resistance in breeding lines identified with improved agronomic performance. Research efforts included a graduate student project aimed at evaluating lines with different combinations of genes for resistance to reniform nematode with reniform susceptible lines. Resistant and susceptible seedlings were quantified for resistance in a growth chamber where plants were grown in a reniform inoculated soil. Results indicated a significant reduction in nematode reproduction for certain combinations of genes conferring resistance. Measurements were also taken to determine if resistance was associated with plant stunting. Results were inconclusive and it was deemed necessary to evaluate lines under reniform infested field conditions. 4. Evaluate newly developed reniform resistant breeding lines in multiple environments to determine competitiveness with high yielding reniform susceptible breeding lines and varieties. The number of reniform resistant breeding lines to consider for testing over multiple environments must be reduced to a manageable number. As no marker testing (to confirm resistance) could be conducted in 2018, reducing the number of lines for multi-location testing will be delayed another year. Resistant lines, as determined by molecular marker analysis, with the highest yield and best fiber quality performance, will be selected for testing in reniform infested and non-infested field conditions. Nematode susceptible commercial check varieties will be used to judge the level of performance of resistant breeding lines. 5. Release reniform resistant breeding lines with improved agronomics traits (yield and or fiber quality traits). Nothing to report.
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2017
Citation:
Guadin, A.G. 2017. Effects of combining Renlon with Renbarb1 and Renbarb2 genes on resistance of cotton (Gossypium hirsutum) to reniform nematode (Rotylenchulus reniformis). M.S. Thesis, Mississippi State University, Mississippi State.
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Progress 10/01/16 to 09/30/17
Outputs
Target Audience:Public cotton breeders, nematodolgists, and graudate students. Progress in developing reniform nematode resistant cotton germplasm lines presented at the 2017 Beltwide Cotton Conferences. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Training Activities - One master's level graduate student was trained in the techniques required to quantify resistance to renifrom nematode in growth chamber studies. In addtion, student gained experience in conducting small plot research required for evaluation of agronomic performance of plant breeding lines, sample collection and tissue preparation for molecular marker analysis, and scoring marker results for reniform resistant plants. Graduate student presented results of study on the effects of different gene combinations on resistance and was recognized with a 1st place award in the graduate student competition. Professional Development - Invesitigator attended and participated in the 2017 National Beltwide Cotton Conferences and presented progress in the development of reniform resistant breeding lines. How have the results been disseminated to communities of interest?Results concerning the progress in the development of reniform resistant breeding lines were presented at the 2017 Beltwide Cotton Conference and in an annual report to Cotton Incorporated. What do you plan to do during the next reporting period to accomplish the goals?Reniform nematode resistant breeding lines could not be evaluated/screened with markers in 2017 due to a lack of funding. Therefore, in addtion to another year of evaluating breeding lines for yield and fiber, lines will be screened with markers to confirm the presence of genes conferring resistance.
Impacts
What was accomplished under these goals?
Nematodes are microscopic worm-like parasitic organisms that feed on roots of crop plants resulting in stunting and a loss in production. The reniform is an important pest of upland cotton in Mississippi and throughout the Southeastern US. Although reniform nematodes are one of the most important pests of cotton in Mississippi, all commercial varieties of cotton are considered to be susceptible to this pest. In 2014, damage from reniform nematode resulted in the loss of an estimated 58,000 bales of cotton in Mississippi. The use of nematicides can be cost prohibitive while cultural control methods, such as planting an alternate crop, may not be a viable alternative. Plant breeding efforts in the current project are directed at developing reniform nematode resistant cotton germplasm lines suitable for use in the development of commercial cotton varieties. Development and planting of host plant resistant cotton varieties would be the most economical and successful approach to reducing losses attributed to reniform nematode. 1. Combine reniform nematode resistance trait from recent G. barbadense derived germplasm lines with yield and fiber quality traits from good performing breeding lines. Breeding lines (F3F5, F4F6, and F5F7) with genes derived from G. barbadense possessing resistance to renimform nematode were evaluated in replicated yield trials (results are pending). Reniform resistant lines were grown in small seed increases to provide sufficient seed for evaluating resistance and for continued performance evaluations. However, due to funding limitations, screening plants with markers to confirm genotype was not possible during the 2017 growing season. As part of a graduate student project, lines with resistance genes derived from both G. barbadense and G. longicalyx reniform were developed to evaluate the effects of different gene combinations on resistance. Lines possessing genes from two different sources of resistance greatly reduced nematode reproduction. 3. Quantify reniform nematode resistance in breeding lines identified with improved agronomic performance. Quantifying nematode resistance requires growing plants in the presence of reniform nematodes in growth chambers and/or in the field. As a very labor intensive evaluation, this component of the research project will not be conducted until the number of reniform resistant breeding lines is reduced to ten or fewer lines based upon yield and fiber quality performance over three years of replicated testing. 4. Evaluate newly developed reniform resistant breeding lines in multiple environments to determine competitiveness with high yielding reniform susceptible breeding lines and varieties. Breeding lines have been evaluated in a single environment for two years with a third year in progress. Each year of testing helps to reduce the number of lines to test and identify lines with the greatest potential to be competitive in yield and fiber performance. Since evaluation in multiple environments requires greater resources, the number breeding lines must be reduced to the top 3-4 lines for evaluation in the regional breeders testing network (RBTN), a multiple environment trial for public cotton breeders. Prior to multi-location testing, resistant genotypes must be confirmed through marker testing and evaluated for nematode reproduction in growth chamber trials. 5. Release reniform resistant breeding lines with improved agronomics traits (yield and or fiber quality traits. Nothing to report.
Publications
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Progress 10/23/15 to 09/30/16
Outputs
Target Audience:Stakeholders of cotton crop commodity organization and a graduate student. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Training Activities - One master's level graduate student was mentored in the techniques of small plot research required for evaluation of agronomic performance of plant breeding populations. Additionally, student was advised in the practical techniques of sampling, data collection, data management and organization. Professional Development - Invesitigator attended and participated in the 2016 National Beltwide Cotton Conferences and the annual meeting of the National Association of Plant Breeders. How have the results been disseminated to communities of interest?Results were distributed on a very limited basis in the form of an annual report to Cotton Incorporated Inc., the primary crop commodity organization for cotton. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Nematodes are microscopic worm-like parasitic organisms that feed on roots of crop plants resulting in stunting and a loss in production. The reniform is an important pest of upland cotton in Mississippi and throughout the Southeastern US. Although reniform nematodes are one of the most important pests of cotton in Mississippi, all commercial varieties of cotton are considered to be susceptible to this pest. In 2014, damage from reniform nematode resulted in the loss of an estimated 58,000 bales of cotton in Mississippi. The use of nematicides can be cost prohibitive while cultural control methods, such as planting an alternate crop, may not be a viable alternative. Plant breeding efforts in the current project are directed at developing reniform nematode resistant cotton germplasm lines suitable for use in the development of commercial cotton varieties. Development and planting of host plant resistant cotton varieties would be most economical and successful approach to reducing losses attributed to reniform nematode. 1. Combine reniform nematode resistance trait from recent G. barbadense derived germplasm lines with yield and fiber quality traits from good performing breeding lines. Due to the long term nature of plant breeding, activities reported for current project encompass both long term and short term breeding efforts. Crosses (hybridization) of reniform resistant germplasm lines and University breeding were previously developed to provide populations segregating for reniform resistance, yield, and fiber quality traits. 2. Identify reniform resistant breeding lines with improvements in yield and fiber quality traits when compared to current available reniform resistant lines. 1) Major activities - All breeding populations, from early generation F2F3 germplasm to more advanced F3F5 breeding lines were subject to marker assisted selection and reniform susceptible plants removed. Each population was planted to a yield trial as well as a single row plot for marker testing and seed increase. Following stand establishment, plants within plots of each population used for seed increase were thinned and then tagged for identification. Screening seed increase populations for transgenic trait contamination must be carried out at some point in the development of breeding lines. However, testing all populations in a single year is cost prohibitive. Therefore, testing is spread out over two or three generations. In 2015, seed increase rows for entries in the GBF2F5 yield trial were tested for transgenic trait contamination. Tagged plants were sampled to test for presence of the two most popular transgenic traits. Any plants testing positive for either transgenic trait were removed prior to marker testing. For entries in the GBF2F5 yield trial, and all other trials, 5-10 plants per seed increase plot were sampled for marker analysis. Each plant was evaluated for presence of three markers (BNL1551, BNL3279, and CIR316) to identify plants with one or more genes for reniform resistance (Renbarb1, Renbarb2, RenLon) and root-knot nematode resistance (Mi1). Approximately 1200 plants within the five different breeding populations were evaluated with markers. Following defoliation, seed from the best appearing marker selected plants within a seed increase row were harvested and bulked to provide sufficient quantities of seed for yield testing in 2016. Prior to harvest of yield trials, boll samples were collected for determining lint percentage and for use in fiber analyses. Boll samples for all yield trials have been ginned and fiber samples submitted to Cotton Incorporated for HVI fiber testing. Results of each yield trial were used to determine which populations to advance for additional replicated yield testing in 2016. Populations exhibiting superior performance in one or two traits, such as lint percentage, lint yield, or fiber quality, were selected for further plant selection to exploit any remaining genetic variability. 2) Data Collected - Molecular marker data was collected from approximately 1200 plants to characterize (genotype) breeding lines for resistance to reniform and root-knot nematode. Plants were selected (resistant) or discarded (susceptible) based upon marker data. Yield and fiber quality data, collected from reniform resistant breeding lines through evaluation in replicated yield trials, was subject to analysis of variance. 3) Summary Statistics and Discussion of Results - Based upon statistical analyses from 2015, selected reniform resistant breeding lines, with yield and fiber quality performance equal to or significantly greater than reniform susceptible commercial "check" varieties, were selected for further evaluation in 2016. Lines selected in 2015 are currently planted in replicated yield trials. Yield, fiber, and marker data collected will be used to identify and characterize germplasm lines as potential parents for use by breeders in the development of commercial varieties resistant to reniform nematode. 4) Key Outcomes - none 3. Quantify reniform nematode resistance in breeding lines identified with improved agronomic performance. Quantifying nematode resistance requires growing plants in the presence of reniform nematodes in growth chambers and/or in the field. As a very labor intensive evaluation, this component of the research project will not be conducted until the number of reniform resistant breeding lines is reduced to ten or fewer lines based upon yield and fiber quality performance over three years of replicated testing. 4. Evaluate newly developed reniform resistant breeding lines in multiple environments to determine competitiveness with high yielding reniform susceptible breeding lines and varieties. The current progress report encomposses the tail end of the 2015 growing up to the time of harvest of the 2016 growing season. To date, breeding lines have been evaluated in a single year-environment (2016), however, results for the current evaluation will not be available until after harvest. Since evaluation in multiple environments requires greater resources, the numberbreeding lines must first be reduced to ten or fewer lines based upon yield and fiber quality performance over three years of replicated testing. Top performing breeding lines will be entered into the regional breeders testing network for multiple environment evaluation during the last year of this project. 5. Release reniform resistant breeding lines with improved agronomics traits (yield and or fiber quality traits). Nothing to report.
Publications
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