Identification and molecular detection of powdery mildew resistance of new bred wheat varieties (lines) in Henan Province, China

Abstract

The powdery mildew resistance of 809 (2009-2013) and 412 (2009-2012) new bred wheat varieties (lines) from Henan provincial regional trials was tested using Blumeria graminis f. sp. tritici (Bgt) isolates E09 and E20, respectively. Molecular markers linked to powdery mildew resistance genes Pm2, Pm4a, Pm8, and Pm21 were used to detect the presence of the individual resistance gene. Among the 908 varieties (lines) inoculated by E09, 199 (21.9%) exhibited resistance. Among the 412 varieties (lines) inoculated by E20, 39 (9.5%) exhibited resistance. Only 15 (3.6%) varieties (lines) showed resistance to both E09 and E20. The 1RS chromatin was detected in 580 out of 908 (63.9%) varieties (lines), indicating the common use of Pm8 or newly developed 1BL/1RS translocation lines in wheat breeding program. Two varieties carried the board spectrum powdery mildew resistance gene Pm21 originating from 6AL/6VS translocation. Eight and two lines might contain the Pm2 and Pm4a loci, respectively. Six varieties (lines) seemed to carry at least two powdery mildew resistance genes. Our results indicated that the newly developed wheat varieties (lines) in Henan province are important powdery mildew resistance resources. However, the common use of 1BL/1RS translocations and a few powdery mildew resistance genes has revealed a very narrow genetic diversity of the resistant resource. It is very urgent to introduce new diversified and broad spectrum powdery mildew resistance genes into the commercial wheat breeding program.