Location: Grain Legume Genetics Physiology Research
Project Number: 2090-21220-003-000-D
Project Type: In-House Appropriated
Start Date: Apr 25, 2023
End Date: Apr 24, 2028
Objective:
Germplasm enhancement and improved genetic understanding of complex traits, including resistance to problematic bacterial, fungal, and viral diseases, and tolerance to drought and to low soil fertility stresses, represent long-term goals of this project. The new genetic information, breeding tools, and breeding strategies will benefit development and release of novel dry bean germplasm and cultivars with enhanced disease resistance, abiotic stress tolerance, and agronomic performance. Breeders will benefit from new germplasm and marker-assisted selection tools, growers from cultivars with improved yield performance and nitrogen fixation, consumers from healthy nutritious food with improved quality, and the environment from reduced fertilizer, pesticide, and water use.
Another long-term goal is to identify the genes underpinning important traits and to leverage that information to develop trait-linked DNA markers to facilitate germplasm and cultivar development. Next generation sequencing technologies, new genomic software, and improved long-read assemblies for reference genomes will contribute to identification of candidate genes underlying economically important traits in common bean and pea. Genetic populations will validate efficient markers for indirect selection of targeted genes in breeding applications. These same populations generated for genetic analyses will be used for breeding and vice versa. Such dual-purpose populations facilitate simultaneous advancement toward our long-term goals (germplasm development and genetic knowledge from genomic analyses). For the next five years this project will focus on the following objectives.
Objective 1: Conduct research to generate breeding populations for improving genetic understanding of complex traits, including resistance to problematic bacterial, fungal, and viral diseases, and tolerance to drought and to low soil fertility.
Objective 2: Develop, evaluate, and release dry bean germplasm and cultivars with enhanced disease resistance and agronomic performance.
Approach:
1. Research Goal: Place genetic factors which control complex stress resistance traits onto physical maps to leverage associated genomic sequences for marker-assisted breeding.
Specific populations (diversity panels, recombinant inbred lines (RIL) will be phenotyped for response to diseases (BCMV, Fusarium root rot, Fusarium wilt, and white mold) and abiotic stresses (drought, low fertility) and genotyped with genomic markers primarily in the form of single nucleotide polymorphisms (SNPs). Genome wide association studies and quantitative trait (QTL) analyses will identify genes conferring resistance to targeted stresses. Putative candidate genes will be sequenced across contrasting genotypes for discovery of SNP markers within the resistance genes. Select SNPs with potential for marker-assisted selection will be assayed by melting temperature Tm-shift analysis. To broaden utilization, Tm-shift assays shown to be effective for marker-assisted selection will be converted to Kompetitive Allele Specific PCR (KASP) markers.
2: Research Goal: Combine QTL and major resistant genes that contribute to durable disease resistance and improved genetic resistance to abiotic stresses in dry bean with quality attributes and enhanced agronomic performance.
Dry bean suffers from diseases and abiotic stresses. QTL and major genes conditioning existing, new, and novel resistance traits can be combined with agronomic performance traits in enhanced germplasm lines and improved cultivars to limit production losses caused by biotic and abiotic stresses.
Bi-parental, 3-way, and 4-way crosses and some backcrosses are conducted in the greenhouse to combine parents with complimentary traits or to further advance traits identified in Objective 1 into commercially adapted backgrounds. Parents are selected from advanced breeding lines, released germplasm and cultivars from other programs, and elite performing inbred lines (RILs, other) often with major genes and QTL (and linked markers) incorporated from the genetic studies in Objective 1.
The F1 generation is advanced in the greenhouse. Marker-assisted selection is applied to select individual plants in segregating F1 populations for traits identified in Objective 1. Harvested F2 populations are planted in nonstress field sites at the WSU-Othello research station. Selected F2:3 progeny rows are planted under nonstress at WSU-Othello. Advanced F2:4 lines are planted in replicated trials in stress and nonstress trials at WSU-Prosser and Othello stations. Often individual F4:5 plants are selected from the better performing lines in these preliminary yield trials. Marker-assisted selection will be used to track traits from the F3 generation on. Materials from the F4 generation and later must perform well (above the trial means) in the purgatory plot under multiple stresses (drought, soil compaction, low fertility, and root rots) and in the non-stress trial used to determine maximum yield potential, to advance for subsequent testing. The advanced F5 and later generation lines will be evaluated in terminal drought and low N trials to further characterize tolerance to specific abiotic stresses.
