Canopy stay-green and yield in non-stressed sunflower

▶ Putative sunflower stay-green hybrids exhibited a significantly slower rate of senescence during the second (fast) phase of leaf area index loss during grain filling. ▶ Stay-green hybrids show a significantly higher leaf area index at physiological maturity (as % of LAI at anthesis). ▶ The anthesis-physiological maturity increment in total oil-corrected biomass and radiation-use efficiency are significantly greater in the stay green hybrids. ▶ The lower radiation-use efficiency values observed in one of the non-stay green hybrids could be attributable to lower specific leaf nitrogen values. ▶ Resistance to stalk breakage was greater in the stay green hybrids. ▶ The stay green observed in the hybrids with slower canopy senescence is functional and not cosmetic.