Phenological, physiological, and agronomic trait variation and heritability in durum wheat (Triticum turgidum L. subspecies durum Desf) genotypes

Durum wheat is the most commonly cultivated tetraploid wheat, accounting for approximately 8% of wheat production worldwide and 10% in Ethiopia. Variation in phenotypic traits indicates genetic diversity and allows genotype identification with desirable characteristics for breeding programs. This study examined the variation, heritability, and correlation of 11 durum wheat phenotypic traits, including days to maturity (DTM), chlorophyll content (CC), spike length (SPL), spikelets per spike (NSPS), grains per spike (NGS), and grain yield (GYD). Based on a simple lattice design, field trials were conducted using 169 durum wheat genotypes in Ethiopia. Various statistical analyses, including Analysis of variance (ANOVA), broad-sense heritability (h2b), and correlation between traits, were conducted. The genotypic variance, environmental variance, and genotype-by-environment interaction were significant for 5 phenotypic and 4 physiological traits, respectively. The three components of phenotypic variance were highly significant (P < 0.01) for DTM and GYD, and both showed moderate heritability.  Based on principal component analysis, three clusters were identified, with the first 2 principal components explaining 37.3% of the variance. This study revealed that early-maturing and high-yielding landraces suitable for cultivation in lowland areas exist in the crop’s gene pool and can be used to develop early-maturing cultivars. Key words: Durum wheat, genotype-by-environment interaction, genotypic variance, grain yield, heritability, landrace.