Genetic analyses of agronomic traits controlled by wheat chromosome 3A

Previous studies with chromosome substitution lines between hard red winter wheat (Triticum aestivum L.) cultivars Cheyenne (CNN) and Wichita (WI) ide ntified genes on chromosome 3A of WI which affect grain yield, yield compon ents, grain volume weight, plant height, and anthesis date. This study was conducted to determine if the trait variation caused by chromosome 3A could be explained by major or minor gene segregation and if these genes are ple iotropic, Linked, or independent on the chromosome. A population of recombi nant inbred chromosome lines for chromosome 3A (RICLs-3A), developed betwee n CNN and a chromosome substitution Line CNN(WI3A), was evaluated in multi- location field trials in 3 yr. Our results indicate significant differences (P less than or equal to 0.05) between parental lines and among RICLs for grain yield, 1000-kernel weight, plant height, and anthesis date, but not f or kernel number per spike, spike number per square meter, and grain volume weight. A 1:1 genetic ratio for anthesis date suggested the presence of a single segregating locus controlling the trait. None of the other agronomic traits could be separated into unequivocal groups and hence, major genes w ere not detected. This indicates that the traits were controlled either by several genes or few genes with enough environmental influence, or both, to obscure their effects. Significant correlations and possible crossover pro ducts between anthesis date, plant height, and 1000-kernel weight suggest t hat these traits were controlled either by linked gene(s) or by pleiotropic genes with additional genes affecting one of the traits.