Handling sunflower (Helianthus annuus L.) populations under heat stress

Sustainable sunflower yield is under threat by a significant rise in global temperatures. Therefore, the development of a heat-resistant sunflower breeding population or hybrid is important for sustainable yield under high temperatures. Although there are a significant number of studies aimed at understanding the mechanism of heat resistance, only few direct approaches were made to improve heat resistance in sunflower. When breeding for heat resistance, the selection criteria are important. A desirable screening criterion should be rapid, highly heritable, and allow for the discrimination of resistant and susceptible ecotypes before reproductive maturity so that undesirable plants can be eliminated. In contrast, destructive selection criteria are not applicable for a segregating population. On the basis of an extensive review of data and experimentation, traits such as leaf and head orientation at the time of anthesis are proposed for practical utilization of sunflower heat-resistant breeding. These traits could be utilized as markers linked with heat avoidance. The traits are simply inherited, non-destructive, non-laborious, and show no impact of the environment and are independent of genotypexenvironment.