Abstract

In order to determine the effect of water deficit and nitrogen fertilizer application on growth indices, yield and yield component of three soybean (Glycine Max L. Merr) genotypes a split plot factorial experiment based on randomized complete block with three replications was carried out. Soybean genotypes (Williams, K1410 and HS95-4118) were subjected to three irrigation regimes (90, 120 and 150 evaporation from class A lysimeter) and three levels of nitrogen fertilizer (30, 60 and 90 kg N/ha). The results showed that, water deficit significantly decreased 1000 grain weight, yield, total dry mater and harvest index. The highest seed per pod (2.59) and maximum 1000 grain weight were obtained from HS95-4118 from Williams’s genotypes, respectively. Although, the HS95-4118 genotype had the highest seed yield (499.89 g/m²). Increasing nitrogen application rates up to 90 kg N /ha increased pod per plant, grain per pod, 1000 grain weight, yield and total dry mater significantly. Maximum harvest index (33.8) obtained from 60 kg N /ha.

Key words:  Growth indices, nitrogen, soybean, water deficit.

Abbreviation

LAR, Leaf area ratio; LAI, leaf /ground area; SLA, specific leaf area;NAR, net assimilation rate; CGR, Crop growth rate; LDM, leaf dry matter; RGR,relative growth rate; LAR, leaf area ratio; LWR, leaf weight rate; GDD, growing degree days.