Water use efficiency in wheat: breeding effects on Argentinean wheat cultivars released between 1971 and 2011

CURIN, FACUNDO; OTEGUI, MARÍA ELENA; GONZÁLEZ FG

Congreso; XXXIII Argentinean Meeting of Plant Physiology; 2021

Water deficit has been signaled as an important determinant of grain yield (GY) gaps between potential and actual GYs. Breeding for improved water productivity is a sustainable mean to reduce this gap. The aim of this study was to evaluate breeding effects on GY and its physiological determinants, including water use efficiencies, of two groups of five cultivars (late -LC and early -EC cycle), grown under six contrasting water environmental conditions during 2016 and 2017 seasons. Analyzed traits were GY, biomass production (BT), harvest index (HI), crop evapotranspiration (ETC), water use efficiency for biomass production (WUEB,ETc) and GY production (WUEGY,ETc). The GY increased at a rate of 0.40 and 0.11 % per year in EC and LC as a consequence of greater WUEGY,ETc. No breeding effects were detected on ETc in both groups. Additionally, BT increase was only detected in EC as a product of improvement of WUEB,ETc in modern EC, while HI explained the GY increase in LC. The breeding efforts had no evident effect on the crop water use but had clear effects on crop biomass production in EC and its partitioning between pre and post-anthesis use in LC. The unintended positive effects of breeding on WUEs are welcome on a global scale, considering that predicted trends of increasing human demand for water will require increased water productivity rather than increased water use by crops.