Association of biochemical traits with grain yield in triticale genotypes under normal irrigation and drought stress conditions

Abstract

Effectiveness of selection of high-yield genotypes under drought stress environments can be improved by using biochemical traits as indirect selection indicators. The objective of this study was to determine the extent to which biochemical traits are associated with triticale grain yield under normal irrigation and drought stress conditions. This field study was conducted to evaluate grain yield and various biochemical traits of 58 triticale genotypes during three consecutive growing seasons (2013-2016). Normal irrigation was applied when 40% of available soil water capacity was depleted. Drought stress was imposed by withholding irrigation for about 40 days from early heading stage to harvest time. In addition to grain yield, proline, malondialdehyde (MDH), hydrogen peroxide (H2O2), protein content, carotenoid, chlorophyll a (Chl a), chlorophyll b (Chl b) and total chlorophyll along with antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), ascorbic peroxidase (APX), and catalase (CAT) were measured. The contents of proline, H2O2, MDH and protein as well as activities of the antioxidant enzymes significantly increased in response to drought stress. Statistical analyses including correlation coefficients, principal component analysis (PCA), stepwise regression and path coefficients revealed that selection of triticale genotypes with low MDH, proline contents and SOD activity as well as high amounts of Chl a and total chlorophyll may improve grain yield under normal irrigation condition. PCA showed negative association between grain yield and antioxidant enzymes under drought stress condition. The results also suggested that low H2O2 and malondialdehyde contents along with high activity of SOD were the selection indicators with significant contributions to triticale grain yield under drought stress condition.