Obtaining and characterizing the high-yielding and stable forms of winter wheat to expand diversity and selection using radiation mutagenesis

Title : Obtaining and characterizing the high-yielding and stable forms of winter wheat to expand diversity and selection using radiation mutagenesis

Abstract:

Irradiation of seeds from two wheat cultivars was carried out using doses of 75, 150, 200, and 300 Gy. Non-irradiated (control, C) and irradiated seeds were grown under field conditions on two water-regime backgrounds: optimal moisture (O) and simulated drought (D). Germination capacity was determined for all treatments. Compared with the control, germination of irradiated seeds decreased depending on the irradiation dose. The lowest germination rate was recorded at the dose of 300 Gy in both cultivars. It should be noted that moisture deficit conditions had an additional negative effect compared with the optimal background. Under drought conditions, germination in the 300 Gy treatment was 15–5% for both cultivars, Alekseevich and Yegdu, whereas under optimal conditions it reached 28% and 24%, respectively. Significant variation in plant growth was observed.

Studies on plant characteristics were conducted throughout the M₁ vegetation period. A slight delay in the onset of developmental stages was noted under both optimal and drought conditions. The strongest irradiation effect was observed at the booting stage in both cultivars: at 300 Gy, the delay reached 7 days, whereas at other doses it ranged from 3 to 4 days. The dose of 75 Gy had virtually no effect on the timing of this phase. The timing of booting and flowering stages varied within relatively narrow limits; however, the maximum effect was observed at doses of 200 and 300 Gy, where delays of up to 3 days were recorded. At lower doses, the onset of these stages was comparable to the control. Considerable variation was observed in plant height, spike length and weight, number of grains per spike, and grain weight. Such variation was also observed in materials selected for yield performance and in subsequent generations.

Beginning from the M₁ generation and continuing in subsequent mutant generations, selection was primarily focused on drought tolerance and yield traits. In mutant generations M₁–M₃, forms significantly exceeding the control variants in drought resistance and yield performance were identified. Mutant forms were characterized using gliadin protein electrophoresis. Different irradiation doses produced different effects on the gliadin protein spectra, with the most pronounced changes observed in materials irradiated at 200 and 300 Gy. Protein and gluten content were determined in promising genotypes grown under the same water-regime conditions. In some mutant forms, total protein and gluten content exceeded those of the original cultivars. Particular attention during selection was given to the stability of beneficial trait expression and the uniformity of the material.

Based on the results obtained, ten M₄ genotypes showing stable expression of drought tolerance and high yield were selected for further multiplication. These mutant forms will be used as source material for breeding programs or, if stability and uniformity are maintained, advanced to the level of a cultivar.

The obtained data expanded the range of genotypes that can be used as donors of valuable traits in the development of new bread wheat varieties.

Biography:

Usmanov R.M. - Doctor of Biological Sciences, Professor. He work at the Institute of Genetics and Experimental Plant Biology of the Academy of Sciences of the Republic of Uzbekistan. He specialize in plant physiology and biochemistry. Areas of interest: stress proteins, remote sensing, digital phenotyping, adaptive responses of plants to unfavorable environmental conditions