Physiological characteristics of South China double cropping super high-yielding rice at active tiilering stage

The main physiological characteristics of six South China super high-yielding rice varieties(combinations).including dry matter weight,chlorophyll contents(a+b)of the functional leaves.leaf area index(LAI),root activity and net photosynthetic rate were measured at the active tillering stage in both early and latecrops.The significance of difference among these physiological characteristics and the effects of these physiologicalcharaetenstics to dry matter weight,and the effects of different environments between early and late crops wereanalyzed by using statistics methods.The required physiological values at the active tillering stage for dynamicplant type breeding of South China double cropping super high-yielding rice were put forward.They were 3.9-4.2mg·g-1in the early crop and 4.0 mg·g-1m the late crop for the ideal chlorophyll contents(a and b)of thefunctional leaves.270—348/μg·g-1·h-1in the early crop and 318 μg·g-1·h-1in the late crop for the ideal rootactivity.2.4-2.7 in the early crop and 3.8 in the late crop for the ideal leaf area mdex.24.8 μmol·m2·s1 inthe early crop and 23.3μmol·m2·s1 in the late crop for the ideal net photosynthetic rate of functional leaves.