Abstract: Photosynthet ic and physiolog ic character w as studied on eight hig h grain yield w heat cult ivars which popularized in Guanzhong area belonging to early, medium and late-maturing , respect ively , to find out the photosynthetic and physiologic mechanism of the high grain yield of early-maturing wheat cult ivars, and the w ay of characteristic improvement further increasing in yield potent ial. The result show that early-maturing and high grain y ield w heat cult ivars tested have fo-l low ing characters: 1. Transpiration rate is higher during peak filling stage; 2. From anthesis to the peak filling stage, net-photosynthet ic rate is higher and steadier; 3. T he cont ribut ion potent ial of photoassimilates to dry mat ter of kernels is larger pref loral; 4. Biomass increased per plant is fairly higher than that of medium and late-maturing post floral; 5. Higher photoassimilates t rans-current coeff icient prefloral, higher dry mat ter increasing coeff icient post floral, bet ter photoassimilates dist ribut ion character and higher harvest index. At the same t ime, biomass of early-maturing and high grain yield cult ivars is lower than that of medium and late-maturing cult ivars, the principal cause is that increased biomass is less from joint ing to anthesis. The w ay of further improv ing early-maturing cult ivars y ield potent ial is keeping or raising harvest index and at the same t ime largely increasing it s pref loral biomass.

Key words: Wheat, Early-maturing , Hig h g rain yield, Photosynthet ic and physiolog ic character

CLC Number: 

• S512.1+1