Intraspecific differentiation of Setaria italica (L.) P.B.: study of abnormalities (weakness, segregation distortion, and partial sterility) observed in F1 and F2 generations

Abstract

Hybrid weakness, segregation distortion, and partial sterility were observed in the offspring of Setaria italica (L.) P.B. following intraspecific crosses. These perturbations occurred in hybrids involving strains from two different geographical origins (China and Europe). However, the parental lines were morphologically similar. In this study, the F1 and F2 generations arising from crosses between Chinese and French varieties were analysed. We hypothesized that the genetic determination of weakness may be due to two complementary recessive genes. The segregation distortion for Adh isozyme could be due to a selection on one type of gamete. Partial sterility was also studied. No meiotic perturbation was observed in semisterile plants, but the tapetal cells were abnormal. The study of F2 generations suggests that the sterility is controlled by a few major genes.Key words: foxtail millet, intraspecific sterility, F2 weakness, segregation distortion, genetic differentiation.