Comparisons of Stripe Rust Response, Grain Yield and Quality between Fungicide Sprayed and Non-sprayed Treatments for Newly Developed Wheat Lines Carrying Different Genes for Adult-Plant Resistance to Stripe Rust

Wheat genes Yr39, Yr48, Yr52, Yr59, and Yr62 conferring different levels of adult-plant resistance (APR) to stripe rust have been introgressed into Chinese wheat cultivars. To determine the effects of five newly developed wheat lines carrying these APR genes on reduction of stripe rust severity, grain yield, and quality, field experiments including non-sprayed and fungicide sprayed plots were conducted in the 2021 and 2022 growth seasons. Compared to the 100% relative area under the disease progress curve (rAUDPC) of a susceptible check cultivar, the resistant lines had relatively low rAUDPC values, ranging from 0.38% in SWUST-445 (Yr62) to 42.04% in SWUST-006 (Yr39 + Yr26) on average of the two years in the non-sprayed plots. The two-time fungicide applications almost completely controlled stripe rust on the susceptible check and the resistant lines in both years. Stripe rust significantly reduced yield by 29.96% in 2021 and by 84.40% in 2022, whereas the yield differences of the resistant lines were not significant in both years, except SWUST-006 and SWUST-445 in 2022. Stripe rust significantly reduced the thousand kernel weight (TKW) of the susceptible check by 30.36% on the average of both years but did not cause significant TKW reduction in the resistant lines. Except few cases, the various measurements for grain quality did not show significant differences for the susceptible check and resistant lines. The results showed that the resistant lines are useful for further development of wheat cultivars with adequate and durable resistance to stripe rust.