Abstract: The experiment was conducted to investigate the differences in dry matter accumulation,as well as potassium (K) uptake and distribution in mid-season indica rice cultivars applied at different decades in China.In this study,9 typical mid-season indica rice cultivars applied in the production in the Middle-lower Yangtze Area during the last 60 years were used under field conditions with randomized block design and three replications.Leaf area index and biomass were progressively increased with the improvement of cultivars.The growth rate of modern rice varieties significantly increased and dry matter accumulation increased higher than those in the early varieties after panicle initiation. The dry matter accumulation of all varieties were roughly the same as the gains of whole plant after heading period, and the dry matter accumulation of modern varieties was significantly higher than that of the early varieties. K contents were progressively increased with the improvement of cultivars.Most of K in all rice varieties was taken up before panicle initiation and there was decreased in the uptake of K from heading to maturity.Most of the potassium in grain comes from the retransfer of the vegetative body,mainly from the transfer of the leaves.There was more K retranslocated from the leaves of the modern varieties Liangyoupeijiu and Yangliangyou 6 compared with the old varieties.Dry matter and K accumulation were progressively increased during the evolution for mid-season indica rice cultivars.Compared with old cultivars,the K translocation into grain of modern cultivars in maturation period was improved.K in grain was mainly translocated from leaves,and K translocation in leaves were progressively increased with the improvement of cultivars.

Key words: Mid-season indica rice, Dry matter accumulation, Potassium uptake and distribution

CLC Number: 

• S511.01

• S143.3