Am. Chiavarino et al., LOCALIZATION OF THE GENES-CONTROLLING B-CHROMOSOME TRANSMISSION RATE IN MAIZE (ZEA-MAYS SSP. MAYS, POACEAE), American journal of botany, 85(11), 1998, pp. 1581-1585
In previous papers we found that the frequency of B chromosomes in nat
ive races of maize varies considerably in different populations. Moreo
ver, we found genotypes that control high and low transmission rates (
TR) of B chromosomes in the Pisingallo race. In the present work cross
es were made to determine whether the genes controlling B-TR are locat
ed on the normal chromosome set (As) or on the B chromosomes (Bs). We
made female f.0B X male m.2B crosses between and within high (H) and l
ow (L) B-TR groups. The Bs were transmitted on the male side in all ca
ses. The mean B-TR from the progeny of f.0B (H) X m.2B (H) and f.0B (H
) X m.2B (L) crosses was significantly higher than that from f.0B (L)
X m.2B (L) and f.0B (L) X 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 pa
rents irrespective of the Bs of the male parent. This indicates that B
-TR is genetically controlled by the 0B female parent and that these g
enes are located on the A chromosomes.