Project Number: 6064-21000-014-000-D
Project Type: In-House Appropriated
Start Date: Apr 14, 2013
End Date: Mar 25, 2018
Develop enhanced cotton germplasm lines with traits useful to the cotton seed industry. Objective 1. Discover molecular markers linked with quality trait loci (QTL) for improved agronomic, fiber, pest resistance, drought, and heat tolerance genes in cotton; develop, evaluate, and release breeding lines with improvements. Sub-objectives 1.1: Screen selected Gossypium barbadense accessions with simple sequence repeat (SSR) markers associated with reniform nematode (RN) resistance. 1.2: Develop root-knot nematode (RKN) and RN resistance germplasm using marker assisted selection (MAS). 1.3: Utilize recombinant inbred lines (RIL) from a random mated G. barbadense Upland (RMBUP-C4) population to identify molecular markers for fiber traits. 1.4: Detect genetic diversity in cytoplasmic genome with chloroplast specific (CP) SSR markers and association with agronomic and fiber traits. Objective 2: Determine identities/functions of genes that mediate resistant and susceptible interactions between select cotton germplasm and RKN and RN. Sub-objectives 2.1: Develop genetic lines designed for associating phenotype and genotype for elucidating effect of candidate resistance gene on RKN. 2.2: Phenotypic/molecular evaluation of chromosomes 11 and 14 in governing RKN resistance in Upland cotton. 2.3: Develop near-isogenic lines for QTL associated with resistance to RN. 2.4: Conduct a time-course phenotypic/molecular evaluation of chromosomes 18 and 21 in governing RN resistance in Upland cotton. 2.5: Identify RN parasitism genes. 2.6: Overexpression of Meloidogyne induced cotton 3 (MIC3) in cotton genotypes containing RKN resistance QTL. Objective 3: Develop strategies using day-neutrality and chromosome substitution lines (CSL) to access genes from the wild G. hirsutum, tomentosum, barbadense, and mustelinum accessions; introgress and release useful germplasm. Sub-objectives 3.1: Develop day-neutral (DN) germplasm from photoperiodic G. hirsutum wild accessions. 3.2: Evaluation and germplasm release of a random mated (RM) population between cultivars and G. hirsutum wild accessions, with alleles for genetic diversity, agronomic, and fiber improvement. 3.3: Evaluate DN germplasm developed from G. hirsutum wild accessions for genetic diversity. 3.4: Develop, evaluate, and officially release two RM populations with introgression from G. tomentosum or mustelinum via CSL. 3.5: Compare/evaluate selected individual CSL from G. barbadense, tomentosum, and mustelinum in crosses with a diverse panel of 5 Upland cultivars. 3.6. Evaluate/compare 9 euploid CSL from G. tomentosum and mustelinum for general and specific combining ability when crossed with 5 diverse Upland cultivars. 3.7. Develop RIL from RM population of G. barbadense CSL crossed with 3 cultivars of Upland cotton (RMBUP-C4). 3.8. Develop CSL. 3.9 Evalute selected euploid CSL from G. barbadense, tomentosum, and mustelinum for fiber/agronomic traits when crossed with TM-1. 3.10: Develop chromosome specific recombinant RIL from partial diallel mating design using the cross of TM-1 and chromosome substitution lines of G. barbadense, tomentosum, and mustelinum for the same chromosome or chromosome segment.
Greenhouse experiments will be used to evaluate lines for root-knot and reniform nematodes. Recombinant inbred lines will also be developed using single seed descent in the greenhouse. Field plots for agronomic and fiber evaluations will be grown in two soil types on the University Experiment Station Farm. The winter nursery in Mexico will be used to advance two generations per year in the breeding. A well equipped molecular marker laboratory will be used in marker analyses. Root-knot nematode will be maintained in a greenhouse using a common host plant. Reniform nematode will be assayed using soil obtained from a field that has a high population of reniform nematode. In addition, a laboratory culture of reniform nematode will be maintained for use in molecular work. Elite germplasm will be released as it is developed and evaluated. Experiments with transgenic reniform nematode resistant lines will be contained in a greenhouse with all the necessary controls. Software packages are available and will be used for molecular analyses. Statistical software in SAS and in R will be used for evaluation of genetic analyses. Irrigation is available and will be used in selected experiments and in the nursery where crosses are being made. Fiber quality will be done on High Volume Instruments available in a commercial lab.