Methods of utilization of regularities in modificational variability of quantitative characters in plant breeding.

The nature of the modificational and genotypic variability of 30 quantitative characters in wheat varieties with different numbers of genes for dwarfing, and nine characters in contrasting pea varieties, differing in leaf type, was investigated. The experimental data, obtained in 1971--1974 and analyzed in the M-220M and Minsk-22 computers, showed a high degree of similarity in the modificational variability of similar quantitative characters for all varieties of the same crop. Significant similarities were also found in the modificational variability of identical quantitative characters for the two species (wheat and peas), which showed that the regularities in modificational variability are generally applicable in biology. The coefficients of variation, calculated from the total data obtained, for modificational (CVm), genotypic (CVg) and overall modificational-genotypic (CVm+g) variability, for the different quantitative characters, may be useful criteria in plant breeding. They may reveal genotypic differences in the quantitative characters in hybrids and mutant populations, and may thus be useful in improving the efficiency of selection of wheat and pea strains.