Use of ultra early and late sowing date in sunflower selection on earliness, productivity and ecological resistance

The main stages of faster creation of early-ripe sunflower variety with the use of natural contrasting environment conditions, ultra early and late sowing date as differentiative background for selection, were presented. The efficiency of modified technique for estimation of selected determinants is considered during creation of early-ripe sunflower variety with high productivity and broad diapason of ecological resistance. It was shown, that the selection on a reduction of vegetation period and an increase of 1000 seed mass is one of the ways of improvement sunflower productivity and expansion of the range of application of this culture.