Location: Crop Genetics Research
Project Number: 6066-21220-016-000-D
Project Type: In-House Appropriated
Start Date: May 16, 2023
End Date: May 15, 2028
Objective:
1. Conduct research utilizing near-isogenic soybean lines that vary for plant architecture genes to characterize effects of plant physiological traits at various growth stages on seed yield, seed composition, and other seed quality traits such as mature seed damage and Phomopsis seed decay.
2. Conduct research to develop and release novel, genetically diverse soybean germplasm with improved seed yield and composition, reduced mature seed damage, and tolerance to abiotic and biotic stresses for sustainable production in the southern United States.
3. Conduct research to determine the inheritance and genomic location of novel genes affecting resistance to Phomopsis seed decay (PSD), and develop phenotypic information that breeders can use to develop resistant germplasm.
3A. Phenotype recombinant inbred line populations derived from PI 587982A for reaction to PSD using a new cut-seedling inoculation technique.
3B. Determine the inheritance and genomic location of new genes influencing or affecting resistance to PSD. Identify new molecular markers for potential use in selecting for PSD resistance.
4. Regenerate priority accessions to produce pure, high-quality seed of MG V-VIII soybean seed from the USDA Soybean Germplasm Collection that are adapted to the southern regions of the United States to maintain their availability and genetic integrity, and evaluate new accessions from that collection for key agronomic traits.
5. Conduct regional field evaluations to collect, analyze and report data on various soybean traits to be used for selection in breeding programs.
Approach:
Soybean is a major crop in the Mid-South U.S., providing income to local U.S. economies and high-quality plant protein and oil for national and world markets. The Early Soybean Production System (ESPS) has been the major soybean production system in this region for the past two decades. The ESPS has successfully increased seed yield and farm income, but the system involves harvesting in late summer, when temperatures and humidity are high. Seed harvested in this period is typically of lower quality in terms of seed germination, diseases, and damage, making it unsuitable as a seed source for planting and prone to price discounting when sold as grain. In addition, seed composition (protein and oil) can be negatively impacted, resulting in a loss of sales to domestic and world markets. There are no cultivars available to U.S. producers that are tolerant to the factors causing seed deterioration (heat, seed pathogens, high humidity) in the ESPS. This project will develop soybeans with tolerance to mature seed damage and with resistance to Diaporthe longicolla (Phomopsis Seed Decay, PSD), determine the inheritance of resistance to PSD, identify useful molecular markers associated with resistance to PSD, and determine the optimum plant architecture for seed quality and yield in the ESPS. The new soybean lines with high seed quality (low damage with acceptable composition) and useful molecular markers will be utilized by public and commercial breeders to develop stable and resilient cultivars that will increase the profits of growers and processors by protecting against late season seed damage. Field, growth chamber, and laboratory experiments will be conducted with the genetic and breeding populations created to achieve the projected goals. U.S. soybean producers, commercial processors and exporters, and those who consume soybean products directly or indirectly will benefit from healthier high-quality soybean seed.
