Study on the Photosynthetic Characteristics of the High-quality Hybrid Rice Varieties of B803A Series

Objective The study aimed to know the photosynthetic characteristics of rice varieties of B You series.Method With Gangyou 725 as CK,the changes of photosynthetic pigments and photosynthetic rates of rice varieties of B You series in each growth period under the special condition of high temperature and drought in 2006.Result The Chl contents in varieties of B You series were higher than CK in the booting,heading,filling and milking stages.Compared with fully tillering stage,the Chla contents in B You series in the booting stage and late growth stage had some increase,and had difference from CK at extremely significant level.The photosynthetic rates of varieties of B You series were highest in fully tillering and booting stages,decreased in heading stage,relapsed in filling stage,and then decreased.Both instantaneous and daily mean photosynthetic rates were higher than CK,and were kept at higher level in clear and cloudy days.The yields of varieties of B You series were all higher than that of CK,in which that of B You 827 was highest,being 8 007.45 kg/hm2,and increasing 3.15 % than CK.The relativity between 1 000-seed weight,available spikes and yield reached significant level,and that between photosynthetic pigments and yield was biggest before and after heading stage.The photosynthetic rates all had significant positive correlation with yield before and after heading stage,being biggest in booting stage and secondary in filling and heading stages.Conclusion High content of photosynthetic pigments,high photosynthetic rates and good photosynthetic mechanism was the physiological foundation of the high yield of varieties of B You series.