Variation in early plant height in wild soybean

It is difficult to evaluate plant height at maturity in wild soybean (Glycine soja Sieb. & Zucc.) and no research about plant height at early growth stages has been reported. The objective of this study was to identify variation for plant height at early growth stages in wild soybean accessions. On the basis of the data collected in 1999, five accessions were selected from each height class (tall, intermediate, and short) for each of three maturity groups (00, II, and IV). These 45 accessions were planted in a completely randomized design with six replications in 2000 and 2003. Three height measurements (H1, 112, and H3) were taken at 10-d intervals beginning 20 d after plant-ing. A multiple comparison t test by Fishers Least Significant Differences (LSD) was used to test the differences among means of three early plant height classes. Highly significant differences were found among years, height classes, accessions within height classes and within maturity groups, and year x accession interaction for H2 measurement, but there were no significant differences among maturity groups and no significant interaction between year and height classes. The optimum time for evaluating differences in early plant height is 30 d after planting. This rapid growth trait in wild soybean could be beneficial for cultivated soybean and a useful trait for evaluating wild soybean germplasm.