High-yielding cultivars in China
1989
Wu, Guangnan | Tsiu, Jiling (Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu (China). Inst. of Agrobiological Genetics and Physiology)
High-yielding rice cultivars in China have 4 basic characteristics: 1. Growth pattern - high total biomass accumulation; more assimilates translocated into grain; 0.50-0.55 harvest index; and medium growth duration (130-150 d). 2. Sources of photosyntates - high optimum leaf area index (9-10); low extinction coefficient (less than 0.4); small leaf area inclination (8-12 for flag leaf); semidwarf (culm length 90-100 cm); high photosynthetic rate (Pn) of a single leaf (high chlorophyll content, high Pn under shaded conditions, etc.). 3. Sink capacity-large panicle extends grain filling for receiving more assimilates; higher spikelet-leaf ratio (number of spikelets/sq cm leaf area) promotes photosynthesis. 4. Nitrogen and mineral nutrition - high N, P2O5, and K20 content in leaves; strong N, P2O5, and K2P absorption ability. High-yielding cultivars absorb more N minerals and metabolize them at a higher level.
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