Improvement of three commercial spring wheat varieties for powdery mildew resistance by marker-assisted selection

Abstract

Powdery mildew (PM) caused by Blumeria graminis f. sp. tritici is one of the most economically important wheat diseases in China. Almost all commercially cultivated wheat varieties are susceptible to PM disease, especially the commercial spring wheat varieties grown in the Northwestern region of China. Pm21 was identified as one of the most effective resistance gene to PM in China, and many wheat varieties carrying Pm21 have been developed and released in different areas since 2010. In this study, 3 PM susceptible spring wheat varieties (Ningchun4, Ningchun47, and Ningchun50) were crossed with a PM resistant line CB037 (carrying Pm21) which is a wheat-Dasypyrum villosum T6AL·6V#2S translocation line, and were then backcrossed with the three spring varieties as recurrent parents, combining the disease test with molecular marker selection. After five times of backcrossing and four generations of selfing, nine advanced lines with strong PM resistance and good agronomic traits (plant height, grains per spike, one thousand kernels weight, and yield) were developed. These lines were further evaluated using the analyses of Pm21-specific markers and genomic in situ hybridization (GISH), and tested in a field trial for agronomic traits including grain yield. Results indicated that all the improved lines were similar to their corresponding recurrent varieties except an obvious difference in plant height. Lines NZ39, NZ42, and NZ46 showed an increase in grain yield (by 1.70–9.38%) and one thousand kernel weight (by 0.4–7.3 g). Compared to their respective recurrent parents, lines NZ41 and NZ46 showed improved bread-making quality, displaying optimal application potential in wheat production.