Race composition ofBlumeria graminis(DC) Speer f. sp.triticiin the south of Ukraine and effectiveness ofPm-genes in 2004–2013

Abstract

The virulence frequency of 750 wheat powdery mildew isolates of wheat genotypes, carrying 23 Pm-genes and gene combinations, was studied over ten consecutive years from 2004 to 2013. Seventy-eight previously known and 39 new pathotypes were identified during this period. The results indicate that the majority of Pm-genes have high level of virulence. Sixty to ninety percent of the isolates were virulent to Pm6, Pm8, Pm8+11, Pm2+4b+8, Pm3g, Pm10+15, Pm10+14+15. The virulence frequency was variable for Pm1a, Pm2, Pm3a, Pm3b, Pm3c, Pm5, Pm7 genes and reached high level in certain years. The virulence frequency to genes Pm20, Pm37, Pm4a+ and to gene combination with Pm3c+5a+35 and breeding lines CN240/06, CN98/06 and CN158/06 ranged from 1 to 8%. Bread wheat lines CN240/06, CN98/06 and CN158/06, derived from interspecific crosses, proved to be highly resistant to powdery mildew.

Virulence and diversity of the Blumeria graminis f. sp. tritici populations in Lithuania and Southern Ukraine

“…Comparison of the obtained values of virulence frequencies of 21 studied Pm-genes with the values of the previous 10 years indicate that virulence frequencies to genes Pm3c and Pm17 decreased, whereas to Pm4b significantly increased. No other significant shifts in virulence of powdery mildew population were detected (Babayants et al, 2015). Virulence frequencies of the Lithuanian powdery mildew population were studied previously on the old differentials in 2000 and 2001.…”

“…Evaluation of leaf segments under controlled conditions makes it possible to easily repeat examination each year and provide fast results. According to the obtained findings and on the basis of our long-term assessment (Babayants et al, 2015), in most cases such evaluation with natural populations of powdery mildew at seedling stage can predict the resistance of the studied material at an adult plant stage in the field (Table 3).…”

“…This may also be partly attributed to the fact that powdery mildew has lost its relevance due to biological competition with other wheat diseases such as tan spot (Pyrenophora tritici-repentis) and Septoria leaf blotch (Mycosphaerella graminicola), which under conditions of modern agriculture appeared more plastic and aggressive, particularly tan spot. Compared with other wheat diseases, powdery mildew is more easily controlled by fungicides (Cowger et al, 2012;Babayants et al, 2015).…”

“…Nowadays, virulence and diversity of Blumeria graminis f. sp. tritici are being studied throughout the world: in the United States (Parks et al, 2008;Cowger et al, 2018), Europe (Carver, 2009;Cowger et al, 2012), Ukraine (Babayants et al, 2015), Iran (Elyasi-Gomari, Lesovaya, 2012), Egypt (El-Shamy et al, 2016; Abdelrhim et al, 2018) and China (Zeng et al, 2014). However, the last nomenclatures for race analysis were developed more than 40 years ago.…”

“…If this is not possible, the genes should be selected on the basis of virulence analysis. Monitoring of virulence frequency and complexity may provide useful information for combining of proper genes to develop and sustain durable resistance to powdery mildew (Babayants et al, 2015).…”