Evaluation of grain yield and its relationship with remobilization of dry matter in bread wheat cultivars under water deficit stress at the post anthesis

Document Type : Research Paper

Authors

1 Faculty of Agriculture, Razi University, Kermanshah, Iran

2 Faculty of Agriculture, Maragheh University, Maragheh, Iran

Abstract

This study was designed to evaluate the effects of post anthesis moisture stress on agronomy traits, storage of stem water soluble sugars and dry matter remobilization of wheat. The pot experiment was laid out in a randomized complete block design (RCBD) in a factorial arrangement with three replications in Campus of Agriculture and Natural Resources, Razi University in Kermanshah state in the west of Iran during the growing season from 2011 to 2012. In the experiment, moisture stress was applied at grain growth stage (soil moisture was around 30% of field capacity from the anthesis stage to the maturity - 65 to 99 Zadoks scale) and different wheat varieties (such as Pishtaz, DN-11, Sivand and Marvdasht) were evaluated as the second factor. The results show that, water stress application at grain growth stages significantly decreased grain yield by decreasing of grain weight. Under application of water stress at grain growth stage, Marvdast and DN-11 cultivars had the lowest grain yield. The occurrence of water stress in experiment, significantly decreased stem dry mater and remobilization. In contrast to this results, in water stress condition stem soluble sugars concentration significantly increased. In water stress conditions, the amount of dry matter remobilization from stem lower internodes (internodes below penultimate) to grain, its efficiency and contribution of its in grain yield increased by 11%, 32% and 121%, respectively. Also, penultimate and stem lower internodes had the highest water soluble sugars concentration under water stress. Water deficiency stress could not increase the remobilization efficiency but in terms of mentioned traits, there were significant differences between cultivars. So, indicated that these traits can be used for identifying drought tolerant high yielding genotypes in winter wheat breeding programs.