Pollen morphology and in vitro germination characteristics of nodulating and nonnodulating soybean (Glycine max L.) genotypes.

Artificial hybridization in highly self-pollinated crop species such as soybean (Glycine max L.) is important for both generating genetic variability and segregation for selection. In higher plants, pollen is an agent for transmission of genetic information over generations. The objective of this study was to measure and compare both morphological (length, width) and in vitro germination (germination percentage tube length) characteristics of pollen from the nodulating soybean cultivar, Bragg, and a nonnodulating Bragg mutant line, Nod 139, obtained following ethyl methanesulphonate treatment. Highly significant (P = 0.007) differences in pollen length were observed between these two genotypes. Similarly, in vitro germination percent (G%) indicated highly significant (P = 0.0001) differences between these genotypes, suggesting that the nodulation trait produces variation in in vitro germination capacity of the pollen. It appears the nonnodulation trait in soybean alters pollen grain length and G%.