Canonical Correlation Analysis of Physiological and Grain Yield-related Traits in Bread Wheat Genotypes Grown in the Greenhouse under Normal and Flowering Drought Stress Conditions

The impact of drought stress on crops is devastating annually, resulting in yield losses of 17%. Research seems, therefore, necessary to improve crop tolerance to drought stress and minimize water losses in agriculture. This study aimed to investigate the relationships between yield and yield components with physiological traits and use these relationships to select high-yielding cultivars under normal irrigation and drought stress conditions at the flowering stage.

To explore the effect of drought stress at the flowering stage, four genotypes were investigated as factor A by factorial experiment based on the randomized complete block design (RCBD) with three replications under the normal and drought stress conditions at the flowering stage as factor B in the research greenhouse of Azerbaijan Shahid Madani University during the 2016-2017 crop season. The relationship between yield and yield components with physiological traits and the relative importance of traits affecting yield were investigated using an analysis of variance, mean comparison, and canonical correlation analysis after measuring the traits of the studied genotypes.

Analysis of variance results revealed significant differences between genotypes for most traits studied. Under normal irrigation conditions and drought stress, the Arum genotype was the best in terms of biological yield, awn length, grain number per spike, and grain number in spikelet traits and the Mihan genotype outperformed others concerning plant dry weight, number of grains per spike, days to spike formation, root dry weight, root volume, and number of grains per spikelet traits. The results of this canonical correlation analysis showed a significant correlation between the canonical variables of yield and yield components with the canonical variables of physiological traits under both normal and stress conditions. To increase grain yield and 1000-grain weight under normal irrigation conditions in the greenhouse, traits of malondialdehyde concentrations, hydrogen peroxide content, proline content, peroxide, and catalase content, and chlorophyll a and total chlorophyll concentrations may be appropriate selection criteria. The results of canonical correlation analysis, under stress conditions in the greenhouse, revealed that to increase 1000-grain weight, number of grains per spike, and grain yield, traits such as malondialdehyde, chlorophyll b concentration, protein content, peroxidase, proline content, chlorophyll a concentration, and catalase are important and influential factors.

According to canonical correlation analysis, it can be argued that under normal irrigation and drought stress conditions in the greenhouse, traits of malondialdehyde concentration, peroxidase content, and chlorophyll a concentration are appropriate selection criteria to increase grain yield.