Duration of sunflower flowering period as influenced by environmental conditions

The results of three year study of modern sunflower hybrids and varieties flowering period dynamics in field experiments are presented. It is shown that the distribution of the number of daily blossoming plants on flowering period days differ from the normal distribution by positive skewness. The values of asymmetry coefficients in hybrids are higher than that one in varieties. It has been established that the duration of flowering varies considerably depending on growing conditions not only in varieties, but also in hybrids. In particular, the unequal time of seedling emergence increases the flowering period of hybrids in 1.5 times or more.