Evaluation of morpho-physiological diversity of durum wheat genotypes under rainfed condition

Knowledge of the amount of genetic diversity in germplasms provides valuable information for the preservation of genetic resources and their use. The aim of this study was to evaluate the diversity of durum wheat genotypes based on morpho-physiological traits and to investigate the interrelationships between traits using the genotype-by-trait biplot (GT-biplot) method.

this study, 124 durum wheat genotypes including 120 breeding lines received from CIMMYT along with 4 check genotypes (Saji, Zahab, Imren and SRN-1\..) with six replications were examined based on an augmented desgin during two cropping years (2017-18 and 2018-19) in the Dryland Agricultural Research Sub-Institute (Sararood Station), Kermanshah, Iran. Genotypes were evaluated based on 22 morpho-physiological traits. Analysis of variance and mean comparison based on the best linear unbaised estimator (BLUE) approach were performed for the studied traits. Heatmap-based correlation analysis was to study the correlation between the studied traits, and the GT-biplot analysis was used to investigate the relationships of traits and determine the morpho-physiological characteristics of the genotypes.

The results of this experiment showed that there was a significant difference between the studied genotypes in terms of the studied traits under rainfed conditions, which indicates a significant genetic diversity in the studied genotypes. Based on GT-biplot analysis method in two years, the studied traits and genotypes were divided into five and eight groups, respectively. Based on the results of correlation analysis and GT-bipot analysis, number of spikes per unit area, plant height, stomatal conductance, biological yield, external peduncle length, spike length, number of days to heading, harvest index and peduncle length were identified as most important traits affecting grain yield under rainfed conditions. In total, based on the results of the selection indices, a number of the studied durum wheat breeding lines in this experiment were selected as the most promising and high-yielding lines for cultivation under rainfed conditions.

The results of this study led to identify a number of durum wheat breeding lines with agro-physiological characteristics superior to the check cultivars, which can be recommended for use in the future durum wheat breeding program to improve drought tolerance and produce optimal yield under rainfed conditions. In total, breeding lines 119, 106, 117, 104, 121, 115, 109, 118, 98, 49 and 124 are introduced as the ideal genotypes under rainfed conditions.