REPRODUCTIVE BEHAVIOR OF SOYBEAN HAPLOIDS CARRYING THEMS1ALLELE

Abstract

Ten maternal haploids (2n = 20) of soybean (Glycine max (L.) Merr.) obtained among twin progeny of ms1/ms1 plants were crossed with normal diploids (2n = 40) and the F1 plants were analyzed cytologically in a search for aneuploids. A total of 67 F1 seed lines from 10 haploids were analyzed cytologically. These progenies consisted of 52 diploids (2n = 40), 1 triploid (2n = 60), 9 tetraploids (2n = 80), one 70-chromosome plant and 4 trisomics (2n = 41). The predominance of diploids in the progeny of haploid .times. diploid crosses suggests that the ms1 allele in the haploids enhanced production of restitution female gametes. Trisomics were similar morphologically to their diploid sibs, although the number of seeds per plant and the number of seeds per pod were slightly reduced. The extra chromosome was transmitted with a frequency of about 30% among a progeny of 20 plants from each of 2 self-pollinated trisomics and 60% among a progeny of 20 plants from another self-pollinated trisomic. It is possible that the restitution-gamete production associated with the ms1 allele carried by the haploids reduced the efficiency of isolating aneuploids.