Oil yield as an integral trait of economic value of sunflower hybrids at high temperatures

Abstract

The aim and tasks of the study. The aim of research was to evaluate sunflower hybrids belonging to different ripeness groups for the main valuable economic traits (yield capacity, oil content in seeds, oil yield) at high air temperatures.

Materials and methods. Sunflower hybrids bred at the Plant Production Institute nd. a VYa Yuryev NAAS and pre-selected by a set of parameters as the most promising were taken as the study material.

Results and discussion. The largest oil yield was obtained in early- and mid-early hybrids. Three main scenarios of the oil yield formation depending on temperature (T) during the sunflower vegetation period. The direction of oil yield variability correlated with temperature changes during all vegetation decades, except high temperatures during the 3^rd decade of June, for hybrids of all the ripeness groups. At high temperatures during any of vegetation decades, short-season hybrids did not exceed early- or mid-early ones in terms of oil yield. Maximum temperature >31°C during the 1^st decade of August significantly reduced oil yield. Variability of oil yield depended on variations rather in the yield capacity than in oil content in seeds.

Conclusions. The year conditions significantly affect oil yield in sunflower hybrids of different ripeness groups. The maximum oil yield is recorded in years with the effective temperature sum during the growing season exceeding the multiyear average, and significant drops or elevations in the effective temperature sum related to the year with the greatest oil yield decrease the trait level. To maximize oil yield at high temperatures, early-season and mid-early hybrids are recommended