Wheat is the third most important staple crop in the world, hence, its sustainable production remained the primary focus due to increasing global consumption. This study aims to determine the genetic potential of spring soft wheat (Triticum aestivum L.) F2 populations for yield traits. Six wheat genotypes were used for diallel reciprocal crossing and a total of 12 hybrids in comparison to parental genotypes were studied from 2015 to 2018 at the Institute of Genetics and Plant Experimental Biology, Academy of Sciences, Tashkent, Uzbekistan. In parental genotypes, the average spikelets per spike were similar, however, the highest index per spike was recorded in cultivars Bardosh (56.8±1.02), Unumli Bugdoy (57.9±1.05), and Sayhun(56.3±0.79). The F2 populations were recorded with the highest number of spikelets per spike and shifted to the right side by 2-3 classes compared to the parental genotypes. The appearance of right-sided regression and identified genotypes with higher 1000-grain weight was observed in the populations of cultivar Bardosh. Populations with higher indices (3.5 to 4.4) than parental genotypes were observed in the cross Bardosh × Unumli Bugdoy (21.7%). The range of variability for 1000-grain weight in the cultivars Kroshka and Bardosh belonged to 2nd class, and cultivars Kayraktash, Unumli Bugdoy, Saykhun, and K-5076 belonged to 3rd class. Populations with 1000-grain weight ranged from 44.0 g to 47.9 g, with a percentage estimate of 63.3% for cultivar Kroshka, and 76.7% for Kayroktosh. In the second generation, the variability range was distributed into eight classes. Larger grains were observed in the hybrids of cultivar Kayroktash. Hybridological analysis of the inheritance of quantitative traits exhibited that the grains per spike were mainly inherited according to the type of dominance of the best parent with a high trait index. The grain number and grain weight per spike were inherited by overdominance type of gene action in the characterized F1 populations.

The paper presents the results of a multi-year assessment of wheat resistance to yellow rust on an artificial infectious background in the field. The dynamics of the disease in the differentiatial varieties with identified resistance genes is studied. The formation of new races of the pathogen after its epiphytotics is revealed. The loss of resistance of certain genotypes that had “effective genes” and were resistant to the disease at the beginning of the experiment is registered. The adult plant resistance, which is of great importance in breeding of resistant varieties of wheat, is analyzed.

Global climate change is leading to water shortages in irrigated areas. This, in turn, requires the selection of crop varieties that are resistant to arid conditions. Thirty varieties of winter soft wheat from the international nursery IWWYT-SA were evaluated under water-deficient conditions. The selection was based on parameters such as grain yield, biomass, growing season, yield components, and yield index. Most of the samples analyzed showed good results under water deficit conditions (without irrigation), with yields ranging from 4 to 5 tons per hectare. In all samples, plant height was average, ranging from 90 to 100 cm, with a biomass of 1600 g/m² and an average of 550 spikelets per square meter. The average weight of a thousand grains was 37.9 grams, although some samples showed significantly lower values. The average harvest index was about 30. Ten promising genotypes were selected for further propagation and implementation in relatively arid areas of the republic.