Over the past decades
Puccinia striiformis f.sp.
tritici (
Pst) has developed into one of the most, if not the most important fungal pathogen in wheat production worldwide. In China,
Pst has caused numerous epidemics with partially devastating yield losses
[ 1]. The occurrence of the “warrior” race in Europe in 2011 also caused significant problems
[ 2].
Pst, like other obligate biotrophs, is characterized by a high degree of genetic variability, especially with respect avirulence/virulence development on specific host varieties. This variability may be caused by mutations, somatic recombination, or recombination during the sexual stage of the fungus. The discovery of the hitherto unknown alternate host for
Pst in 2010
[ 3] put a new focus on the role of sexual recombination in this variability
[ 4,
5]. With now 35 barberry species identified as potential alternate host for
Pst in one of China’s bread baskets (Gansu, Sichuan, Shaanxi, Yunnan and Tibe)
[ 6,
7], elucidating the role of the sexual cycle of
Pst has become even more important. The work entitled “Determination of heterozygosity for avirulence/virulence loci through sexual hybridization of
Puccinia striiformis f. sp.
tritici” by Yuan TIAN, Gangming ZHAN, Xia LU, Jie ZHAO, Lili HUANG, and Zhensheng KANG, in this issue (DOI: 10.15302/J-FASE-2016114), is an important work in the light of giving breeders some indication as to which wheat varieties to use for future crosses. From the 25 wheat varieties tested, 17 turned out to carry resistance genes for which the corresponding
Pst avirulence/virulence genes turned out to be heterozygous. Such lines should be excluded from future breeding programs as chances are high that resistances generated in the new cultivars will be rapidly overcome. As such this paper constitutes a major advance in understanding the intricate interaction of
Pst and its host wheat, and at the same time provides practical cues for future breeding programs.
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