The effect of directed selection by criteria on the spontaneous variability of varying traits in the offspring of the varietal population of squash

Abstract

The article presents the results of testing a varietal population of 945 squashes on spontaneously genetically variable (heterozygous) signs of repeated directional selection according to the same criteria over a number of generations. The coefficient of variation in the indicator “fetal shape index” in the F₇ variants of this population ranged from 5.5 to 12.5 %. Intra-linear variability on this basis was low and medium. In the tested variants of F₈, the coefficient of variation on the basis of the “fetal shape index” indicates an average degree of variability of this trait (V = 10.2–15.0 %). The range of variability of the trait in the F8 variants was the smallest. The coefficient of alignment of the fetal shape of variants F₇ was 87.5–94.5 %, variants F₈ – from 85.0 to 88.2 %. The coefficient of variation on the basis of “sugar content” in variants F₇ ranged from 9.5 to 27.0 %, alignment - from 73.0 to 90.5 %. Variability on the basis of “sugar content” is insignificant, medium and high. The F₈ variants on the basis of “sugar content” have an average coefficient of variation (12.3–18.5 %), which generally indicates the best alignment of the F₈ variants of the 945 varietal population on this basis. The coefficient of equalization of the sugar content of the F₈ variants ranged from 81.5 to 87.7 %. The range of variability of this trait in F₈ variants is the smallest. Using the type of directed selection to increase the adaptive potential, resistance and viability of the varietal population 945, 66 partially homogeneous variants (lines) F₉ with a certain level of heterozygosity were selected according to the characteristics that determine heterosis and the main economically valuable characteristics (heart-shaped fruit, gray-green bark color, orange fruit pulp, sugar content from 9.0 to 11.4 %).