Comparisons of Oat Population Developed by Intraspecific and interspecific Hybridization1

Abstract

Characteristics of four populations developed by interspecific (Avena sterilis ✕ A. sativa3) hybridization and two populations developed by intraspecific (A. sativa ✕ A. sativa) hybridization were studied to determine their potential utility in a spring oat breeding program. Six A. sativa cultivars and four randomly chosen A. sterilis introductions served as parents in the development of the six populations, each containing between 510 and 576 lines. The experiment was conducted over two years and three locations in Iowa. There were no significant differences among the six population grain yield means. Overall, intraspecific populations had a vegetative growth rate mean of 8% greater than the interspecific population mean, although individual interspecific populations had means equal to intraspecific populations. Interspecific populations did not display consistently larger genetic variances for either trait. Intraspecific populations had between 1.8 and 2.3% and interspecific populations between 0.0 and 1.8% high transgressive segregates for grain yield. Intraspecific populations had between 0.0 and 4.1% and interspecific populations had between 0.8 and 3.1% high transgressive segregates for vegetative growth rate. Differences between observed and expected population means suggest that non additive gene effects influenced grain yield and vegetative growth rate in both population groups. Subdivision of genetic variances in interspecific populations indicated that recombination between the genomes of the two species for loci controlling grain yield and vegetative growth rate was random. A population developed from a broad sample of A. sativa cultivars was a more efficient short‐term strategy for grain yield and vegetative growth rate improvement than was the introgression of limited samples of randomly chosen A. sterilis germplasm.