THE INFLUENCE OF ALIEN GENES OF RESISTANCE TO COMMON DISEASES ON AGRONOMIC CHARACTERISTICS OF BREAD WINTER WHEAT IN THE DRY CONDITIONS OF SOUTHERN UKRAINE

Abstract
Introduction. A combination of fungal diseases and drought can cause significant yield losses of winter wheat (Triticum aestivum L.). It is known that alien traits introduced through wide hybridisation into wheat genome contribute to breeding of cultivars with a higher yield potential in arid environments.
Aim. The impact of alien genes of resistance to widespread diseases and morphological characters on the main agronomic traits in the arid environments of the Southern Steppe of Ukraine was analysed.
Methods. The lines were grown in a control nursery designed in 5 and 10 m2 plots on the black earth area in the 2019–2021 vegetative periods consecutively under the arid system without irrigation. The plant material included 153 experimental wheat lines of different origin with six check cultivars for the arid climate zone of Ukraine. The data on eight agronomic (quantitative scores) and six plant pathological (point scores) traits were collected and subjected to statistical analysis to comprehend the contribution of the diversity and connections between the characters.
Results. Due to the successful introgression of alien genes from all sources involved in hybridisation, the majority of lines were resistant to one of the rust species. The lines derived from the sample containing the translocation 1BL.1RS in the karyotype and Triticum timopheevii Zhuk. in the pedigree were resistant to all rust species. The lines containing the alien genes Lr42 and Hs showed a higher yield than the recurrent cultivar and standard ones. There was a negative correlation between the protein content and grain yield in 2020 (r = −0.40***). A weak positive correlation was found between the yield and resistance to yellow rust (Rsp = 0.19* in 2019 and Rsp = 0.26*** in 2020) or tolerance to Septoria leaf blotch (Rsp = 0.14 in 2019 and Rsp = 0.27*** in 2020). Under drought conditions, the yield reduced by 32.5% in 2020 and by 70% in 2021. The drought resistance index directly correlated with the yield in the dry conditions of 2020 (r = 0.69***), and also was inversely proportional to the yield values (r = −0.26**) obtained in favorable conditions.
Conclusions. The studied experimental lines have a potential for use in the wheat improvement programs for resistance to the diseases in Southern Ukraine. For further breeding, eighteen lines with a high weight of 1000 kernels, protein content, and yield, and resistance to drought or disease were identified, and four promising drought-tolerant lines have been selected.
 