Elite-II synthetic hexaploid wheats as a potential source of resistance against yellow rust

Abstract

Stripe rust is a continuous lingering threat to wheat yield and quality through out the world. Wild progenitors of wheat had been proved as novel sources for resistance against various biotic and abiotic stresses. Synthetic hexaploid wheats (SHW) have been made by crossing these wild progenitors. In this study, we screened Elite-II SHW international set acquired by the International Centre for Improvement of Maize and Millet Mexico (CIMMYT) against yellow rust inoculum having virulent genes against Yr1, Yr4, Yr6, Yr7, Yr8, Yr9, Yr12, Yr17, Yr18, Yr26, YrSp, YrSu, YrSk and YrA collected from diverse areas of Pakistan. We found 15 genotypes resistant at seedling stage, and infection type (ITs) ranged from 2 to 4. Field resistant scoring was done as resistant, moderately resistant, moderately susceptible and susceptible for adult plant stage. Ten genotypes were found resistant both at the seedling and adult plant stage, seven genotypes were found susceptible at seedling and resistant at adult plant stage, three genotypes had shown moderate reaction against yellow rust, five genotypes were found resistant at seedling and susceptible at post seedling stages, eight genotypes were found susceptible both at seedling and adult plant stage. Genotypes resistant at both the stages are novel sources for genetic diversity and resistance against yellow rust. Genotypes susceptible at seeding and resistant at adult plant stage can prove to be the excellent novel sources for adult plant resistance (APR) or high temperature adult plant resistance (HTAP). Genotypes with moderate resistance can prove to be the sources of minor genes, and genotypes having resistance at seedling stage and susceptible at adult plant stage are recommended for segregation of resistance suppressor genes or HTAP genes.