Common bunt in organic wheat: unravelling infection characteristics relevant for resistance breeding

Common bunt caused by Tilletia tritici and T. laevis has re-emerged as a major threat to wheat yield and quality, especially in organic farming. Resistance against its causal agents is present in the wheat gene pool and provides the most economically efficient and sustainable way to combat the disease since seed treatments approved for organic farming are rare and do not always provide full protection. We tested a winter wheat diversity panel with 128 lines for common bunt resistance in Austria and Czechia, and evaluated the applicability of marker-assisted selection (MAS) via Kompetitive Allele-Specific PCR markers in genotypes with high variation in their genetic background. Field trials were conducted across two years and artificially inoculated with local bunt populations. The virulence patterns of these inocula differed between locations and only 15% of the tested genotypes showed stable resistance across test sites. Number and weight of bunt sori relative to the total number and weight of wheat grains in sampled ears revealed that partial infections of ears were frequently appearing. Forty-two breeding lines harboring combinations of four different resistance QTL were developed through MAS. Out of these, a quarter were resistant with a maximum of 5% common bunt incidence. On the other hand, only six out of 46 tested commercial cultivars and breeding lines showed no infection with common bunt, underlining the present scarcity of bunt-resistant cultivars for organic wheat production. By this study we showed that MAS is a useful tool to speed up the selection of resistant lines even in populations with highly diverse genetic backgrounds, and that it is efficient in pyramiding resistance loci and thereby improving the level of resistance

Methodology of using molecular markers for detection of resistance genes to wheat rusts, powdery mildew and eyspot, and dwarfing genes of wheat

The aim of the publication is to summarize detailed protocols for detection of following resistance genes to wheat rusts, powdery mildew and eyspot (Lr10, Lr19, Lr24, Lr26+Sr31+Yr9+Pm8, Lr28, Lr34+Yr18, Lr37+Yr17+Sr38, Pch1), and dwarfing genes of wheat (Rht-B1 a Rht-D1) using molecular markers based on polymerase chain reaction (PCR). The protocoles are reliable optimized for routine use in a common laboratory with basic equipment needed for PCR

Methodology of diagnostics and control of stem base diseases of wheat

The methodology presents optimized techniques for a detection of the species of fungi causing stem base diseases and suggests the control measures

The Use of Real-Time PCR for the Pathogen Quantification in Breeding Winter Wheat Varieties Resistant to Eyespot

The reaction of twenty-five winter wheat cultivars frequently grown in the Czech Republic to inoculation with Oculimacula yallundae and Oculimacula acuformis was evaluated in small plot trials from 2019 to 2021. The eyespot infection assessment was carried out visually using symptoms on stem bases and quantitative real-time polymerase chain reaction (qPCR). The cultivars were also tested for the presence of the resistance gene Pch1 using the STS marker Xorw1. Statistical differences were found between cultivars and between years. The lowest mean level of eyespot infection (2019–2021) was visually observed in cultivar Annie, which possessed resistance gene Pch1, and in cultivar Julie. Cultivars Turandot and RGT Sacramento were the most susceptible to eyespot. The method qPCR was able to distinguish two eyespot pathogens. O. yallundae was detected in higher concentrations in inoculated plants compared with O. acuformis. The relationship between the eyespot symptoms and the pathogen’s DNA content in plant tissues followed a moderate linear regression only in 2021. The highest eyespot infection rate was in 2020 due to weather conditions suitable for the development of the disease

Cereal diseases from sowing to harvest (determination and protection options):Methodology for practice

The fungal and virus diseases are still very actual topics due to the high proportion of cereals in crop rotation and large cultivated area. The cereal crops often decimated by fungal diseases like eyespot, powdery mildew, smuts, rusts, Fusarium head blight and brown leaf spot diseases. The virus diseases include Barley yellow dwarf virus – BYDV, Wheat dwarf virus – WDV and Wheat streak mosaic virus – WSMV are also very important due to the epidemic incidence in some years. This methodology summarizes the current knowledge of these fungal and virus diseases, focuses on the description, symptoms, occurrence, field and laboratory diagnostics and possibilities of crop protection against these diseases. Individual diseases are ranked in the order of their occurrence in the agroecosystem. The methodology can serve the farming communities and agronomist as a key to identifying the diseases infecting wheat crop