Localization of the genes controlling B chromosome transmission rate in maize (Zea mays ssp. mays, Poaceae)

Abstract

In previous papers we found that the frequency of B chromosomes in native races of maize varies considerably in different populations. Moreover, we found genotypes that control high and low transmission rates (TR) of B chromosomes in the Pisingallo race. In the present work crosses were made to determine whether the genes controlling B‐TR are located on the normal chromosome set (As) or on the B chromosomes (Bs). We made female f.0B × male m.2B crosses between and within high (H) and low (L) B‐TR groups. The Bs were transmitted on the male side in all cases. The mean B‐TR from the progeny of f.0B (H) × m.2B (H) and f.0B (H) × m.2B (L) crosses was significantly higher than that from f.0B (L) × m.2B (L) and f.0B (L) × m.2B (H) crosses. The results show that the B‐TR of the crosses corresponds to the H or L B‐TR of the 0B female parents irrespective of the Bs of the male parent. This indicates that B‐TR is genetically controlled by the 0B female parent and that these genes are located on the A chromosomes.