Effects Of Sowing Date And Cultivating Pattern On Yielding Potential And Grain Quality Of Japonica Rice Varieties In The Nanjing Area

Rice is a superior crop with high and stable yielding in the Nanjing area. The constant growing area per year is along 0.12 millions hm~2 and its total yield 711 thouands tons, amounting to 82.5% the annual total yield. The yield potenial of rice directly affects the yield of provisions all the year round. Rice production plays paramount important role on the agricultural production of the whole municipality. In the wake of executing "Japonica Rice Engineering", Japonica rice in Nanjing municipality has become the major variety of rice. The strain extension and reasonable utilization of Japonica rice varieties with high yield and excellent quality are of paramount importance to the yield increase and quality improvement of the provisions. In this experiment through the experimental statistics and observation analyses of yields, quality and other traits of different Japonica rice varieties under different sowing stages and culturing types, observations and analyses were conducted on the adaptable effects of temperature and light to the yields and growth as well as development of different kinds of Japonica rice varieties under Nanjing natural ecological conditions so as to offer dependence for the reasonable utilization of varieties on the large field growing area.The research results were as follows:1. Under the ecological conditions at Nanjing region, the growth and development stage may shorten following the delay of sowing stage, each delay of sowing stage for 10 days, the heading period may be delayed for 1-3 days, growth and development stage may short for 7-8 days. The number of total leaves on the main stem was almost without any change, the effect of sowing stage to yield was mainly caused by the change of the number of total panicle flowers, with relatively small effect to the grain weight.Those quality indexes of different varieties which were affected by temperature and light conditions were chalk ate, chalkiness, and gelatinous rates, whereas the brown rice percentage, polished rice percentage were relatively stable. There was relatively significant difference among varieties about the effects of temperature and light to the yield and quality.