07 декабря 2019г.
Armenia is the ancient homeland of numerous crops including wheat. Wheat cultivation started approximately in XIII-XII millennium B.C. in Armenian highland and even now wild relatives of wheat are quite widespread in Armenia. It is well known that the wild relatives of crops play a significant role in the development of cultivars with desired characteristics and provide valuable and stable genes for disease and pests resistance, high protein content, tillering, frost and drought resistance and other economically desirable attributes. Wild progenitors of cultivated wheat species are an important source of variability for breeding programs to obtain new cultivars with improved quality, stable yield and reduced economic and environmental costs.
The main goal of the presented research was comparative characterization of the pollen of some cultivated and wild wheat species growing in Armenia. The objectives of our research were genotypes from Triticum species including cultivated T. aestivum L. var. Nairi and var. Delfi (both 2n=42), T.durum Desf. var. arandani (2n=28) and wild T. boeoticum Boiss. (2n=14). The material of flowers was sampled from the experimental station of the Scientific Center of Agriculture (Echmiadzin). For estimation of pollen fertility and measurement of pollen grains the method of the acetocarmine staining was used. The data of pollen fertility were obtained on the basis of analysis of circa 5000 pollen grains in each variant. The evaluation of measurements of pollen grains were carried out on the base of analysis 200 randomly taken pollen grains per sample using Motic 10 digital microscope by ImageJ software. Mean values, standard deviation (SD) and coefficient of variation (CV) were calculated for each sample in Excel.
In reproductive biology the key role plays the development and formation of both female and male gametophytes. In our study the results of pollen fertility demonstrated wide range in investigated species. The high levels of pollen fertility more than 90% were revealed for all genotypes excepted T.aestivum var. nairi with fertility 79,8%.
Morphometric analysis of pollen revealed the formation of pollen grains with average sizes from 78,7±25,97 for T.boeoticum to 122,57±9,48 for T.aestivum var. delfi. As it was expected the pollen size increases with the ploidy level of the genotypes. At the same time the interspecific differences were registered between nairi and delfi varieties of T.aestivum with pollen average sizes 107,61 and 122,57 respectively. In our study the highest level of CV was registered for T.aestivum var. nairi and T.boeoticum 30-33% which could present more potential for adaptivity to climate change.
The presented results can provide essential basis for future strategies in agriculture management in Armenia to reach target yields. Besides, the wheat cultivars and wild species with high viability and high quality will be recommended as important source for target breeding. Their research is important for obtaining new hybrids in terms of enhanced capability adapting to the changing environment.
