Effect of heat and moisture stress treatments on seedling growth of wheat (Triticum aestivum L.) varieties

A pot experiment was conducted in sand culture to evaluate the effect of heat and moisture stress treatments on seedling growth parameters of eight wheat varieties sown on two dates under laboratory condition in 2003. Seeds obtained from normal sowing recorded significantly higher shoot length and root and shoot dry weights than those from late sown crop. Unfavorable conditions (moisture/heat) for growth of the seedlings under moisture/temperature stress adversely affected seedling growth. Among varieties, UP 2425 and Raj 3765 consistently showed higher seedling vigour values compared to other varieties which may be attributed to their large seed size. Variety WH 542 with lowest grain size produced lowest shoot and root dry weight. Therefore, it appears that seedling vigor parameters are related to seed size which was evident from significantly positive correlation between 1000 grain weight and shoot length, shoot dry weight and root dry weight. The values for acquired moisture stress tolerance were higher than acquired heat stress tolerance. The result of acquired stress tolerance of seedlings showed that varieties UP 2425, Raj 3765 and PBW 373 had better tolerance to stress situation as compared to other varieties. Acquired stress tolerance for heat stress (r = 0.87) and moisture stress (r = 0.80) showed positive correlation with 1000 grain weight.