Precise Transfer of Useful Variability for High Grain Micronutrients from Wheat-Aegilops Substitution Lines into Bread Wheat through Pollen Radiation Hybrid Approach

Radiation hybrid approach is very efficient approach for transfer, localization, tagging and mapping of genes in living organisms. This technique relies on radiation induced breakage and analysis of marker loss and retention in radiation hybrid population. Precise gene transfers have been obtained in wheat by pollen irradiation. In the present study selected wheat-Aegilops substitution lines were used for fine transfer of genes for higher concentration of Fe and Zn through pollen radiation hybrid approach. Crosses were made between wheat cultivar Triticum aestivum cv. PBW343 having Lr24, Lr28, Yr10 and Yr15 genes for rust resistance as the recipient parent and gamma irradiated wheat-Aegilops substitution lines as the donor parent. The cross seeds were treated with 0.2% Bavistin and germinated in trays. The roots of these seedlings were fixed for GISH analysis. A high proportion of sterile plants were observed in radiation hybrids indicating the effectiveness of the pollen radiation treatment. GISH analysis of the selected fertile healthy F₁ pollen radiation hybrid plants indicated stable introgression of U^k and S^k chromosome fragments in the wheat genomes. The anchored SSR molecular marker data of some selected seeds radiated plants also confirmed the U^k and S^k fragments. Some of the irradiation induced transfers showed higher grain Fe and Zn content indicated that some fine and compensating transfers carrying the genes for high grain iron and zinc without linkage drag could be obtained. The work on further characterization of these pollen radiation hybrid derivatives using gene based markers or GBS is in progress.