CHROMOSOME PAIRING AND ASSOCIATIONS AT MEIOSIS IN HAPLOID SOYBEAN (GLYCINE MAX)

Abstract

Nine haploid plants (2n = 20) of soybean (Glycine max [L.] Merr.) (2n = 40) were examined for meiotic chromosome pairing. At pachytene, from 0 to 6 regions of apparent chromosome pairing were observed per cell. From 0 to 4 bivalents per cell were observed at diakinesis and 0 to 5 at MI-AI. Secondary associations were commonly observed at MI-AI, although these may have been artifacts of chromosomal stickiness. The degree of pairing suggests considerable duplication of the soybean genome, indicative of polyploidy. The haploids were obtained from genetic male-sterile (ms1/ms1) seed parents. All the haploids produced coenocytic microspores, a characteristic also common in the ms1/ms1, diploid genotype, which indicated that the haploids were hemizygous for ms1 and were of parthenogenetic origin.