QUANTITATIVE VARIABILITY AND CORRELATION DEPENDENCE OF PRODUCTIVITY AND GRAIN QUALITY INDICATORS OF SPRING SOFT WHEAT
The data on the correlation and regression dependence of productivity, grain-unit and thousand-kernel weight of spring soft wheat are given in the article; the parameters of quantitative variability of these characteristics in the south-western part of the Central region of Russia are estimated. In the course of the studies it was established that the variety Zlata had the highest grain yield of 5.97 t/ha, with a significant addition to the standard 0.64 t/ha of the variety Darya. All studied varieties of spring soft wheat produced food grain of the first or second class with a grain-unit of more than 750 g/l. In the south-western part of the Central region of Russia mean grain yield of spring soft wheat made up 5.18-6.56 t/ha, thousand-kernel weight was 38.1-39.1 g, with grain-unit of 766-771 g/l. The analysis of statistical parameters of quantitative variation of yield, grain-unit and thousand-kernel weight of the studied varieties of spring wheat showed low variability of these indicators within a species (Triticum aestivum L.). The coefficients of variation ( V, %) were low. They confirmed the typicalness of mean species indicators being 4.03-5.00% for yield, 0.68-1.02% for grain-unit and 2.47-2.98% for thousand-kernel weight. The representativeness of the data obtained appeared to be high, the experimental error (S <sub>%</sub>) did not exceed 2.50%. The multiple correlation and regression analysis has shown, that there is a direct, mean close relationship (r=0.57; d=0.32) between the yield of spring soft wheat varieties (Y) and the thousand-kernel weight (X1). The dependence of these characteristics is of the form of a linear regression equation: Y=5.68+0.36(Х1-38.7). The correlation between the thousand-kernel weight and grain-unit was lower, some mean positive relationship (r=0.30, d=0.09) was recorded.