The Relationship Of Photosynthetic Characteristics With Dry Matter Production And Yield Of Double Season Super Rice

A field experiment studied the relationgship of photosynthetic characteristics with dry matter production characteristics and yield in different growth stages, with8super early hybrid rice varieties and6super late rice varieties as materials. The results showed as follows:(1)In the early, middle and later growth period, the net photosynthetic rate of super early and late rice was higher than the control variety, especially in middle and later period. The daily-average net photosynthetic rate of top leaf in super early rice was higher than the control, the largest advantage appeared in the bright sunlight at noon and the weak light in the night. In different growth periods, under sunny conditions, the net photosynthetic rate of top leaf which had90degree with light was superior to control in super early rice. In the middle and later growth periods, under cloudy conditions, the net photosynthetic rate of top leaf had significant advantage.(2)In the later growth period, the SPAD decline rate of super early and late rice was lower than the control. The net photosynthetic rate and SPAD of efficient leaves were higher in super early rice, especially in the second leaf and third leaf. In milky stage, the difference of photosynthesis and respiration rate was significant higher than the control.(3) In different growth period, SPAD of super early and late rice was higher than the control. SPAD of super early and late rice had obvious advantage at early and later growth period. In different growth period, the Chlorophyll a content and carotenoid content of super early and late rice varieties were higher than the control, Chlorophyll b content was lower.(4) The leaf area index and photosynthetic potential of super early and late rice were higher than the control in the whole period. The leaf area index and photosynthetic potential of super early rice had obvious advantage in the middle and later growth periods, there was no obvious advantage at early growth period. In the early, middle and later growth period, the leaf area index and photosynthetic potential of super late rice were higher than the control significantly.(5) The total dry matter accumulation of super early and late rice were significantly higher, compare the control. The dry matter accumulation of super early rice had obvious advantage at middle and later growth periods. The dry matter accumulation of super late rice were higher than the control significantly in every growth stage. The relative growth rate and population growth rate were higher in the whole growth period. Dry matter output, output rate and contribution rate of the stem and sheath were significantly higher.(6) The yield of super early and late rice were significant higher than the control. The yield of early season rice had a significant positive correlation with the total dry matter accumulation, relative growth rate and population growth rate in the whole growth period, and had a significant positive correlation with the dry matter accumulation of the middle and later growth periods. The yield of late season rice had a significant positive correlation with the total dry matter accumulation and population growth rate in the whole growth period, and had a significant positive correlation with the dry matter accumulation of the early and later growth periods.