Wheat Antioxidants Changes and Grain Yield Variation under Drought Stress

Abstract

Antioxidants provide a defense line against adverse effects of free radicals released in plant cells under drought stress. Accumulation of antioxidants may link with higher grain yield in environmental stress conditions. The aim of this study was to evaluate antioxidants accumulation under drought stress and their relationship with grain yield variation. Reactions of 100 wheat landrace varieties and two commercial cultivars (Shiraz and Bezostaya) to drought stress were tested by two treatments’ including normally irrigation regime throughout the growth cycle and stopped irrigation from heading stage as drought stress in 2010-2011. Results indicated that drought stress triggers plant reactions via accumulation of proline as non-enzymatic and catalase and peroxidase as enzymatic-antioxidants. Correlation analysis showed that grain yield increases when antioxidants increase and proline was more responsive than other antioxidants in plants dealing with water deficit stress after heading. Genotypes had different reactions to drought stress and categorized in susceptible and tolerant groups. KC4144, KC4641, KC4779, KC3885, KC4529, KC4863, KC4907, KC4528, KC4511 and KC4840 had higher enzymatic activities. These genotypes that had highest grain yield in both irrigation and drought stress conditions can be used as parental lines in construction of mapping populations in order to locate QTLs responsible for drought tolerance. Therefore, categorizing studied genotypes as drought- tolerant and susceptible would help a better programming of breeding for higher grain yield and stability under low-income environments.