| The experiment was conducted in 2017 and 2018 at Shiliu town,Donghai county,Longitude and latitude are 34°35 'north latitude and 118°45' east longitude.The experimental base outside Yangzhou University.The experimental varieties were medium maturity medium japonica rice varieties:Nanjing 2728 and Nanjing 505,and late maturing japonica rice varieties:Nanjing 9108,Fujing 1606,Fengjing 3227 and Wuyunjing 80 as the experimental material.Under the condition of two ripe rice and wheat planting in Huaibei area.Seven sowing dates were set for May 10(S1),May 17(S2),May 24(S3),May 31(S4),June 7(S5),June 14(S6),and June 21(S7),forming seven different temperature and light treatments(TL1,TL2,TL3,TL4,TL5,TL6,TL7).The effects of temperature and light on the yield and its components,photosynthetic material production and rice quality in Huaibei area were systematically studied.It provides theoretical and practical basis for the formation of high quality and high yield of japonica rice and the efficient and rational utilization of temperature and light.The main test results are as follows:(1)With the delay of sowing time,the heading and maturity dates of the two growth types of rice were delayed,and the days from sowing to heading stage and the whole growth period decreased.Under different sowing dates,the growth process of rice changed,and different temperature and light treatments were formed.The daily average temperature,maximum temperature and minimum temperature of the two growth types TL1 to TL7 from heading to maturity and the whole growth period decreased significantly;the effective accumulated temperature and active accumulated temperature of each growth period decreased significantly;the accumulated sunshine hours and accumulated radiation from sowing to heading and the whole growth period decreased.In 2017,the daily average sunshine hours of two growth types TL1 to TL7 decreased from sowing to heading,increased from heading to maturity,and decreased during the whole growth period;the daily average radiation of each growth stage decreased.In 2018,the average daily sunshine hours of TL1 to TL7 from sowing to heading stage increased,while the average daily sunshine hours from heading to maturity stage decreased,and the average daily radiation from sowing to heading stage increased first and then decreased,while the average daily radiation from heading to maturity stage and the whole growth stage decreased.(2)The yield and its components of TL1 to TL7 were significantly reduced.Medium maturity medium japonica rice was reduced by 2.88-3.02 t hm-2,Late maturing japonica rice was reduced by 3.40-3.86 t hm-2,respectively.The yield of the two growth types of rice had a significant negative correlation with the daily average temperature and the lowest temperature from sowing to heading,a significant positive correlation with the effective accumulated temperature and the active accumulated temperature,a significant positive correlation with the sunshine hours,the accumulated sunshine hours,the daily average radiation and the accumulated radiation,and a significant positive correlation with the temperature from heading to maturity and the whole growth period.The yield was positively correlated with the accumulated sunshine hours,daily average radiation and accumulated radiation.For medium maturity medium japonica rice,the average daily temperature from jointing stage to heading stage was 26.0-26.8?,and from heading stage to maturity stage was 19.7-22.0?.For late maturing mid japonica rice,the average daily temperature from sowing to heading stage was 26.0-26.4?,and from heading to maturity stage was 18.9-20.6?,which could achieve higher yield.In order to ensure the safety and maturity of japonica rice in Huaibei area,the medium and late maturity japonica rice should be sown before June 14 and May 31,respectively.In order to achieve higher yield requirements,the medium and late maturity japonica should be sown earlier than May 27 and May 18,respectively.(3)The number of tillers and panicles and the rate of ear formation of the two growth types of TL1 to TL7 were significantly decreased in jointing stage,heading stage and mature stage.Dry matter weight and economic coefficient decreased significantly at heading stage and maturity stage,dry matter accumulation decreased significantly from sowing to heading stage and from heading to maturity stage,leaf area index decreased significantly at heading stage and maturity stage,and photosynthetic potential decreased significantly at all growth stages.The population growth rate from TL1 to TL7 had a trend of increasing from sowing to heading stage,but the change range was small,the population growth rate from heading to maturity stage decreased significantly;the population growth rate from TL1 to TL7 from sowing to heading stage had no obvious change rule,and the population growth rate from heading to maturity stage decreased significantly.The net assimilation rate of middle maturity japonica from TL1 to TL7 from sowing to heading stage increased,and decreased significantly from heading to maturity stage;the net assimilation rate of late maturity japonica from TL1 to TL7 from sowing to heading stage did not change significantly,and decreased significantly from heading to maturity stage.(4)The brown rice rate,milled rice rate and milled rice rate of TL1 to TL7 of temperature and light treatment of three types of rice decreased significantly;the chalkiness rate and chalkiness degree of medium maturity soft rice decreased significantly;the chalkiness rate and chalkiness degree of late maturity soft rice and conventional rice decreased first and then increased.The protein content of TL1 to TL7 increased significantly and the gel consistency decreased significantly.In 2017,the content of amylose decreased first and then increased,and in 2018,the content of amylose increased;the content of protein and amylose increased significantly in late maturing soft rice and conventional varieties TL1 to TL7,and the gel consistency decreased significantly.The appearance,viscosity,balance value and taste value of TL1 to TL7 rice decreased significantly,while the hardness increased significantly.The daily average temperature from heading to maturity of medium maturity japonica soft rice varieties is less than 19.7?,the effective accumulated temperature is less than 556?,the daily average temperature from heading to maturity of late maturity japonica soft rice varieties is less than 19.0?,the effective accumulated temperature is less than 513? the daily average temperature from heading to maturity of late maturity japonica conventional varieties is less than 18.9?,and the appearance quality of rice is relatively better when the effective accumulated temperature is less than 515?.The average daily temperature from heading to maturity of medium maturity japonica soft rice is higher than 19.7?,the effective accumulated temperature is higher than 556?,the average daily temperature from heading to maturity of late maturity japonica soft rice is higher than 19.0?,the effective accumulated temperature is higher than 513?,and the average daily temperature from heading to maturityof late maturity japonica conventional rice is higher than 18.9?.(5)In order to ensure rice maturation,the effective accumulated temperature of medium and late ripening medium japonica varieties during the whole growth period should be no less than 1917.3 ? and 2098.9?;the effective accumulated temperature of medium ripening medium japonica varieties during the period from sowing to heading period should be 1563?1653?;the effective accumulated temperature during heading period should be 556-667 ?;and the effective accumulated temperature during the whole growth period should be 2119-2297?.The effective accumulated temperature of late-ripening medium japonica varieties is 1713?1793 ? from sowing to heading,514?616? from heading to maturity,and 2228?2338? during the whole growth period.Rice can achieve high yield.The effective accumulated temperature of middle-ripe and middle-ripe japonica varieties from heading to maturity is greater than 556?,while that of late-ripe and middle-ripe japonica varieties from heading to maturity is greater than 513?,which can achieve higher taste quality. |
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