Location: Sunflower Improvement Research
Project Number: 3060-21220-034-023-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 1, 2022
End Date: Dec 31, 2025
Objective:
1. To characterize white mold resistance of new dry and snap bean lines using multi-site white mold disease nurseries and greenhouse resistance tests using Sclerotinia sclerotiorum isolates with aggressiveness that is best able to differentiate lines; and 2. To evaluate genotype x environment interaction, adaptability, and stability of genotypes evaluated in the multi-site white mold disease nurseries over the past 13 years.
Approach:
The first objective will be accomplished by evaluating the performance of candidate lines (new potential bean cultivars) in multiple sites alongside known susceptible, moderately susceptible, and moderately resistant cultivars. Studies will be conducted in both field sites and in greenhouse plantings. For greenhouse evaluations, current bean breeders will provide lines from recombinant inbred line (RIL) populations, interspecific hybridizations, introgressions from wild Phaseolus vulgaris, and local lines identified in earlier NSI-supported research. The modified straw test and updated severity scale will be used in the greenhouse studies. For field evaluation, advanced pre-release lines will be tested at multiple field locations to identify the most consistent and widely effective white mold resistance/avoidance. Field tests will have two rows of each entry and a common susceptible cultivar resulting in a three-row plot, 4.6 m (15 ft.) long, replicated three times in a randomized complete block design. Plots will be managed to maximize yields, e.g. use of windbreaks, frequent irrigation and misting, which favor white mold. The CIAT 1-9 scale will be used to assess white mold resistance in the field. The second objective will be accomplished by utilizing previously collected white mold resistance data to conduct a multi-year analysis of our field data and perform genotype by environment interaction (GEI) analysis in current years. Data from the multi-site white mold nurseries will be analyzed using appropriate linear mixed models to handle the heterogeneity of the data. Management information will be collected to analyze genotype-by-environment-management interactions. All data will be analyzed using ASReml and other packages in the R statistical environment.
