Biotechnologie, Agronomie, Société et Environnement (Jan 2015)
Raising potential yield of short-duration rice cultivars is possible by increasing harvest index
Abstract
Description of the subject. Further increases in rice yield potential are generally thought to require greater biomass assimilation. This study presents a new cultivar that draws greater yield from increased harvest index (HI). Objectives. Our objective was to identify the physiological traits that are critical to the high yield of a recently developed short-duration rice cultivar Guiliangyou 2 (GLY2). Method. GLY2 and a check cultivar Yuxiangyouzhan (YXYZ) were grown in a field at the Experimental Farm of Guangxi University, Guangxi province, southern China in early and late rice-growing seasons in 2013. Grain yield, yield components, canopy characteristics including leaf area index (LAI), leaf N content (LNC), leaf area duration (LAD) and assimilation rate (NAR), biomass accumulation, and harvest index were determined for each cultivar in each season. Results. GLY2 produced 17–38% higher grain yield than YXYZ with the same growth duration. Spikelets per m2 and grain weight were higher in GLY2 than in YXYZ by 11–13% and 6–17%, respectively. GLY2 had higher LAI and LAD but lower LNC and NAR than YXYZ. As a consequence of the compensation between the canopy characteristics, there was no significant difference in biomass accumulation between the two cultivars. Harvest index of GLY2 was 13–23% higher than that of YXYZ. Large sink size, high remobilization of stored reserves and maintained biomass production after heading were responsible for the high HI of GLY2. Conclusions. Our study suggests that it is possible to increase HI together with grain yield by improving the potential sink size and the remobilization of stored reserves while maintaining high LAI and LAD in short-duration rice.
