Study On Cultural Characteristics Of Two Line Hybrid Rice And Strategy For High Yield

Study on Cultural Charactcristics of Two Line Hybrid Rice and strategy for High yield Postgraduate: Cm Huirong Supervisor: Professor Wang Yulomg (Agri.Coll.,Yangzhou University, Yangzhou, 225009) Abstract Cultural characteristics of two line hybrid rice combinations were investigated in order to seek the way to achieve high yield. The experiment was conducted under the field condition in 1999, which employed 6 two line hybrid rice combinations and three nitrogen levels. Results showed that: (1 )The two line hybrid rice had lower 1000-grain-weight, but significently more spikelets per panicle than two CK varities, which resulted in more spikelets and output per area. (2)Relatively small Leaf area per stem led to low leaf area index but weight or grain per leaf area and spikelet surviving ability were relatively high. (3)The maximum tiller-stem number was higher than CK, while surviving panciles ratio was lower. (4)Two line hybrid rice had higher economic coefficient but no superiority on biomass, only during internode elongation to heading stage or 20 days after heading to harvest stage, it had high ability on material producing. (5)Nitrogen application enhanced the number of panicles and grain output per unit area. (6)Nitrogen application also promoted tillering, but resulted in lower ratio of surviving panicles 63 2001 ~眎t)2 (7)Nitrogen application enlarged leaf area per stem, delayed leaf declineing, caused weight and grain per leaf area to decrease but had little effect on spikelet surviving. (8) Nitrogen fertilizing enhanced average LAI, at the same time reduced NAR of each life period. biomass production increased due to more extended average LAI. (9)In yield components, spikelet per in2 which was effected mostly by panicle number per in2 had the significant relationship with grain yield per in2. Tillering during 7/3(monthldate) to 7/10 strongly affected number of panicles. (l0)Biomass production, which was effected mostly by biomass accumulated after heading, was closely related to grain yield. Enhancing average LA] or NAR during heading to harvest could promote biomass production, the latter was more efficient. (11 )Weight or grains per leaf area were closely related to NAR. Decreasing leaf area per stem in heading stage to a suitable level could ehance NAR after heading.