Assessment of genotypic variation in soybean for water use efficiency (WUE) using Carbon Isotope Discrimination (CID) technique

Genotypic variations were analyzed in a set of 91 diverse soybean accessions for 10 morphological traits and water use efficiency (WUE) using Carbon Isotope Discrimination (CID) technique. The Euclidean distance was used as a measure of dissimilarity among the accessions and Ward's method was applied to classify the genotypes and draw the dendrogram. Moderate level of variability for CID (19.95 to 22.91%) was observed among the genotypes. A significant negative correlation (–0.241) between water use efficiency (WUE) and days to maturity was observed. The genotypes in two clusters (Cluster I and V) differed significantly for most of the traits including CID (20.76 Vs 22.43%), days to 50% flowering (50.75 Vs 39.43), days to maturity (117.25 Vs 107.67), plant height (94.70 Vs 63.50 cm), and yield per plant (8.05 Vs 11.03 g). Such genotypes hold promise for developing high yielding and drought tolerant (low CID) genotypes through hybridization.