Assessment of morphological and anatomical variability in Triticum species, Aegilops species, interspecific and intergeneric hybrids

Abstract

Wheat species and wild relatives offer promising resources for wheat improvement and research in the current period of the genetic narrowing of modern wheat cultivars. The present study was performed to evaluate the morphological and anatomical traits of 20 diverse genotypes including Triticum and Aegilops species with intergeneric and interspecific wheat hybrids, which were compared with modern bread and durum wheat cultivars locally adapted to rainfed and irrigated conditions. The study showed that stomata density and size ranged from 55.3 to 108.6 stomata/mm2 and 401.4 to 1296 µm2, respectively, in the selected genotypes. Moving tetraploid to hexaploid genotypes, increased chromosome numbers yielded lower densities of large stomata in wheat species and hybrids. In this regard, the stomatal patterns of two hexaploid wheat hybrids and a wheat species including ‘Agrotriticum’, ‘Aegilotriticum’, and T. compactum, were of low density and large size stomata compared to T. durum cv. ‘Kunduru 1149’ with high density and small size stomata. Interestingly, the wild progenitor of the bread wheat D genome, Ae. tauschii, had a high density of the smallest stomata among the studied genotypes. The study further indicated that morphological parameters decreased under rainfed conditions compared to those under irrigated conditions, with levels varying among the genotypes. The rainfed flag leaf area and 1000-grain weight varied from 0.9 to 23.7 cm2 and from 7.3 to 61.9 g, respectively under rainfed conditions, while they ranged from 1.2 to 35.7 cm2 and 11.5 to 69.9 g under irrigated conditions. The flag leaf area had a significant and strong association with 1000-grain weight under rainfed (r2= 0.79) and irrigated (r2 = 0.77) conditions. T. turanicum and T. polonicum were characterized by the significantly highest 1000-grain weight in both rainfed and irrigated conditions. This study suggests that these wheat species with high 1000-grain weight might have promising alleles to be transferred into durum wheat to increase grain yield.