Physiological and biochemical characters of hybrid rice in Dongting Lake region, China
1989
Cheng, Q. | Hu, N. | Jing, N. | Huang, F. (Hunan Agricultural Coll., Changsha (China))
In two yield trials of V64 type combinations, hybrids outyielded conventional varieties by 15-28%. Hybrids have these advantages. They have good photosynthetic characters. Leaf area index (LAI) in hybrids was 17-34% higher than that of conventional varieties at heading, and photosynthetic potential 21-26% higher from tillering to heading. In the Dongting Lake region [China], solar radiation is 84.9 kcal/sq.cm from April to November. Hybrid rice can absorb more solar energy because of larger LAI. The photosynthetic intensity was 8-15% higher for hybrids than for conventional varieties at early growth and 6-27% higher at middle growth stages. Another advantage is that they have stronger root systems at early and middle growth stages. Hybrid rootability was 21-34% higher than for the conventional check at the seedling stage. Exudative intensity was 3-34% at middle growth stages. This indicates that hybrids have wider root distribution and more ability to absorb water and fertilizer. Lower respiration intensity is another advantage. Average dry matter accumulation in the hybrids was 46-99 kg/ha per day more than in the check. Shorter growth duration is also an advantage. Because of their shorter growth duration, hybrids mature before the cool fall temperatures, which limited production of earlier hybrids in the Dongting Lake region. These hybrids are virus disease resistant. Disease percentage in V64 infected by green leafhopper (1.5% transmission rate) was 11-12%. However, larger sink size and insufficient source in the new hybrids resulted in more unfilled panicles.
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