A morphological and molecular taxonomic study of the species Triticum durum L. and Triticum aestivum L. (Poaceae) cultivated in Nineveh Governorate, Iraq
Abstract
The present research involved studying the morphological and molecular characteristics of six durum and soft wheat varieties of the genus Triticum L., belonging to the grass family Poaceae and cultivated in Nineveh Governorate. These included three durum wheat varieties (Triticum durum L.) (Hawler 4, Kuya 18 and Buhouth 22) and three soft wheat varieties (Triticum aestivum L.) (Kalar, Maarouf and Hassad). The aim was to establish reliable taxonomic guidelines based on the morphological and molecular characteristics of the studied species. The varieties were compared morphologically, demonstrating that they possessed favourable characteristics for isolating the studied varieties. These characteristics included vegetative traits such as plant height, flag leaf dimensions and colour and ligule shape; reproductive traits such as spike and awn length, glume length and surface covering and seed dimensions and lint density. The reproductive traits proved to be the most reliable taxonomically, as the presence of hairs on the glume distinguished coarse from soft wheat. For molecular diagnosis, the rbcL gene produced a uniform band at approximately 600 bp and the analysis revealed a close relationship between the varieties Hawler 4 and Buhouth 22 (PX120105.1, PX120107.1; genetic distance 0.0000) respectively, which were of the species T. durum L. and between the varieties Maarouf and Hassad (PV953212.1, PX120103.1; genetic distance 0.0000) respectively, which were of the species T. aestivum L., while the Kalar variety diverged into an independent branch relative to the other cultivars of its species T. aestivum (genetic distance 0.0501). Incorporating the reproductive morphological characters with the rbcL-based molecular identification of the Iraqi durum and soft wheat germplasm revealed a practical key for their identification; however, highly polymorphic markers are needed to accurately differentiate between the closely related cultivars and to support breeding and conservation of the germplasm.