Growth Characteristics of Two Super-High-Yielding japonica Hybrid Rice Combinations

Growth and dry matter production characteristics,yield formation and yield components of rice under super-high-yielding (12.0 t /hm2) cultivation were analyzed using two japonica hybrid rice combinations (Lingxiangyou 18 and Changyou 1) in paddy field. The results showed that the number of panicles,the number of grains per panicle,the number of secondary branches per panicle and the number of spikelets on secondary branches under super-high-yielding cultivation(SHYC) were significantly higher than those under traditional high yielding (10.5 t/hm2 to 11.0 t/hm2) cultivation(CK). The seed-setting rate and 1000-grain weight under SHYC were a little higher than those under CK,but without significant difference. Before the critical leaf-age for productive tillering,rice under SHYC grew faster and at the critical leaf-age for productive tillering the number of stems and tillers was up to the expected value,and leaf area index,photosynthetic potential,dry matter accumulation and crop growth rate were larger than those under CK. From the critical leaf-age for productive tillering to elongation,rice under SHYC had a steady growth with less ineffective tillers and lower peak number of seedlings,and its leaf area index,photosynthetic potential,dry matter accumulation and population growth rate were lower than those under CK. After elongation,with a steady decline in growth and a high productive tiller rate,rice under SHYC had higher leaf area index,photosynthetic potential,dry matter accumulation and population growth rate than under CK. Super-high-yielding rice had an obvious growth superiority. Especially after heading,leaf area index,photosynthetic potential,dry matter accumulation and population growth rate were significantly higher under SHYC than under CK.