Thitiporn Machikowa and Paisan Laosuwan

pp. 365 - 368

Abstract

Fourteen soybean lines/varieties were evaluated at Suranaree University of Technology experimental Farm, Nakhon
Ratchasima, Thailand, in 2006-2007 using a randomized complete block design with 3 replications. The objectives of the study
were to investigate the correlations among some characters of soybean and to verify direct and indirect effects which will be
used for the selection for seed yield. Eight characters were evaluated for phenotypic- genotypic correlations and path coefficients. These were days to flowering, branches per plant, nodes per plant, pods per plant, seeds per plant 100 seeds
weight, days from flowering to maturity and yield. Means for yield and its components were significantly different among all
genotypes for all characters. Significantly positive phenotypic correlation was observed between seed yield and days to
flowering. Further-more, genotypic correlation showed that seed yield was positively correlated with all characters except
100 seeds weight. Pods per plant gave the highest positive direct effect on seed yield, followed by branches per plant. In
addition, the indirect effects of most characters were high through pods per plant. The results obtained from genotypic
correlations and path analyses showed that the efficiency in the selection for seed yield in early maturing soybean should
increase through the selection of pods per plant.