| Field experiments were conducted in 2013 in Yiliang to study the effects of water stress on grain yield, yield component, functional leaf area and SPAD value during panicle differentiation to full heading stages. The results showed that compared with normal irrigation mode, grain yield was decreased by 11.03% under water stress during panicle differentiation to full heading stages, reaching a significantly different level. Effective panicles, total grains per panicle and filled grains per panicle were decreased by 4.58%, 7.21%, 8.53%, respectively, which was found to be significant on filled grains per panicle. Effective leaf area index, low efficient leaf area index and total leaf area index at full heading stage became decreased by 13.60%, 10.55%, 12.92%, respectively. SPAD value of the first, second and third leaves from the top were decreased by 1.26%, 1.32%, 2.69%, respectively. Under water stress during panicle differentiation to full heading stages, the descendent rates of total grains per panicle, filled grains per panicle and fertility rate were low in the highly drought resistant varieties, whereas high in the poorly drought resistant varieties. Functional leaf SPAD value of the highly drought resistant varieties had been barely affected, showing an increasing tendency, but that of the poorly drought resistant varieties was decreased. |