The method of ‘main component’ in the grain sorghum breeding for arid conditions of the lower Volga region

In the breeding process of agricultural crops, including sorghum, the use of multivariate statistics methods makes it possible to determine the correlation between morphometric traits, yield elements and biochemical parameters of grain in the model population, as well as to identify the load of hypothetical factors. The purpose of the current study was to identify the correlations between morphometric traits, yield elements and biochemical parameters of grain, which characterize the load of hypothetical factors in the model grain sorghum population. For practical breeding process, there have been analyzed 13 economically valuable traits in 27 grain sorghum varieties, developed by the FSBSI Russian Research and Project-technological Institute of sorghum and maize “Rossorgo”. There has been established a different variation degree of the traits of grain sorghum; a strong variation degree was established for such traits as ‘flag leaf area’, ‘the largest leaf area’, ‘panicle stem’, ‘productive tilling capacity’, ‘weight and number of grains per panicle’ (27.3–35.2%); a weak variation degree was established for such traits as ‘protein percentage’ and ‘starch content’ in grain (2.8–8.6%). The group with an average degree of variation includes the traits ‘plant height’ after 30 days of growing and at ripening period, ‘panicle length’, ‘1000-grain weight’, and ‘grain yield’ (10.1–15.6%). When analyzing the matrix of correlation coefficients, there were calculated the hypothetical factors with a contribution of more than 5% to the accumulated variance. There has been built a correlation pleiad, which made it possible to demonstrate mean (r = 0.51–0.68) and strong (r = 0.76–0.94) correlations. There have been considered six hypothetical factors reflecting the total contribution to the accumulated variance, Z-1 – 40.86%, Z-2 – 13.76%, Z-3 – 11.85%, Z-4 – 8.74%, Z- 5 – 6.69%, Z-6 – 5.99%. The first hypothetical factor is determined by such traits as ‘the largest leaf area’ and ‘flag leaf area’ (0.78–0.80), ‘weight and number of grains per panicle’ (0.84–0.91), ‘grain productivity’ (0.77) and ‘productive tillering capacity’ (- 0.78). The results obtained are used in breeding programs to develop grain sorghum varieties and hybrids adapted to the arid conditions of the Lower Volga region.