Evaluation of Grain Quality of Triticale Lines under Late-season Drought Stress

Development of cultivars better adapted to drought stress in the arid and semi arid climatic conditions is considered as a major breeding objective. Grain quality is a trait with physico-chemical complexity depending primarily on genotype, is strongly affected by environmental factors and their interactions. Effect of terminal drought stress on quality traits of 18 triticale lines, comprising of 9 doubled haploids (DH) and 9 F7-8 lines, and two bread wheat cultivars (Rowshan and Kavir), was investigated under two separate experiments (with/without drought stress) at the Research Farm of College of Agriculture, Isfahan University of Technology, Isfahan, Iran, during two growing seasons of 2007-2009. Plants were grown under full irrigation until the mid-jointing stage when drought stress was applied. In this experiment, amount of glutenin, gliadin, gliadin/glutenin ratio, dry gluten content, sediment volume SDS, crude protein, carbohydrate, ash, grain test weight and grain yield were evaluated. The results showed that triticale lines performed superior to wheat cultivars under drought stress conditions considering grain yield, but wheat cultivar possessed the highest values for majority of quality traits. Grain yield had negative and significant correlation (r = - 0.56**) with grain protein content under no-stress conditions, and with grain test weight (r = - 0.67**) under stress conditions. Accordingly, genotypes with more grain test weight and protein content under stress conditions were probably affected by drought stress. and this may be due to lower of plant performance under drought stress conditions than those under normal conditions. Grain yield produced under drought stress conditions negatively and significantly correlated with dry gluten and protein under non-stress conditions. Overall, based on the results of this research, it was concluded that under drought stress conditions at the reproductive stage, DH triticale line number 2 performed superior for grain quality and biochemical adaptation to drought stress.