Effects Of Different Sowing Period On Quality Of Indica Rice

The Southern Henan rice area is one of the main rice cropping areas in Henan Province.In order to realize the rational utilization of temperature and light resources for rice cropping in this area and the coordination of high yield and quality of rice varieties,the experiment was carried out in Pingqiao District,Xinyang City in 2019 and 2020.Three medium indica rice varieties were selected:Zhaoyou 5431,Zhongzheyou 8 and Y Liangyou 900,and five sowing periods were set:April 15,April 30,May 15,May 30 and June 14,the changes in temperature,light intensity,and light time during rice growth were recorded.After maturity,the quality of rice such as processing quality,appearance quality,cooking and eating quality,and nutritional quality were measured.Effects of light conditions on rice quality of three indica rice varieties,in order to reveal the effects of different temperature and light conditions on indica rice quality,and to provide theoretical support for highquality indica rice cultivation techniques in Southern Henan rice areas.The main results of this study are as follows:1.The growth stages of the three varieties are different,and the temperature and light conditions in the growth period are also different.In general,after heading,with the delay of the sowing period,the temperature,light time and light intensity of the three varieties showed a downward trend from heading to maturity after five sowing periods.The accumulated temperature,accumulated light time and accumulated light intensity of Zhaoyou 5431 in the first sowing period decreased by 34.6%,15.0%and 64.0%respectively compared with the fifth sowing period.The accumulated temperature,accumulated light time and accumulated light intensity of Zhongzheyou 8 in the first sowing period decreased by 33.0%,15.2%and 58.8%respectively compared with the fifth sowing period.The accumulated temperature,accumulated light time and accumulated light intensity of Y Liangyou 900 in the first sowing period decreased by 45.0%,28.6%and 62.3%respectively compared with the fifth sowing period.In terms of accumulated temperature,Y Liangyou 900 has the largest decrease,followed by Zhaoyou 5431;the cumulative illumination time of Y Liangyou 900 has the largest decrease,and the decrease of Zhaoyou 5431 and Zhongzheyou 8 is similar;The decline is the largest,followed by Y Liangyou 900,and Zhongzheyou 8 has the smallest decline.2.Processing quality:The brown rice rate,milled rice rate and whole milled rice rate of the three varieties all showed a trend of first rising and then falling with the delay of the sowing period,reaching the highest value in the third sowing period,and then decreasing,and in the fifth sowing period.The brown rice rate,milled rice rate and whole milled rice rate reached the lowest value,especially the whole milled rice rate.The temperature from heading to maturity in the third sowing stage is the most suitable,so that the three varieties can obtain suitable grain filling rate and achieve suitable brown rice rate,milled rice rate and milled rice rate.Among the three varieties,Y Liangyou 900 has the best processing quality.3.Appearance quality:The chalky grain rate and chalkiness degree of the three varieties showed a trend of first decreasing and then increasing with the delay of the sowing period.The chalky grain rate and chalkiness degree were the lowest and the quality was the highest in the second and third sowing periods.Well,the temperature and light conditions made the chalky grain rate and chalkiness degree the highest and the quality the worst in the fifth sowing stage.Generally speaking,in terms of chalkiness,Y Liangyou 900 has the lowest chalkiness,the grain aspect ratio Zhaoyou 5431 is the highest,Zhongzheyou 8 is in the middle,Y Liangyou 900 has the lowest aspect ratio,and Y Liangyou 900 is low chalky.The white,low aspect ratio appearance quality is good,similar to the processed quality results.4.Cooking and eating quality:With the delay of the sowing period,the temperature and light gradually decreased,the amylose content first decreased and then increased,the second sowing period was the lowest,and the fifth sowing period was the highest,but the amylose content was moderate.In the range,guesses are related to genetic factors.The disintegration value of the three varieties was the highest in the second sowing period,and the alkalinity value was negative in the first three sowing periods.From the perspective of viscosity,Zhongzheyou 8 was the best.5.Nutritional quality:The general trend of protein content increases first and then decreases with the delay of the sowing period.The protein content of the third sowing period is higher than that of other sowing periods,in addition to the fifth sowing period of Y Liangyou 900 and the fourth and fifth sowing period of Zhaoyou 5431 in 2020.The protein content of the fourth and fifth sowing periods and the rest of the sowing periods were all within a moderate range,and the nutritional quality was moderate.The protein content of Zhongzheyou 8 was relatively stable.To sum up,in the Southern Henan rice area,with the delay of the sowing period,the temperature and light from heading to maturity showed a downward trend.Through path analysis,RDA and contribution rate analysis,it was concluded that the temperature and light conditions at the grain-filling stage of different sowing periods were closely related to the formation of rice quality.Among them,the temperature 10 days after heading is the primary factor affecting rice quality,and the light intensity 10 to 20 days after heading is the second factor affecting rice quality.Therefore,by adjusting the sowing period of rice to change its growth environmental conditions,and then adjust the temperature and light conditions after heading,and improve the quality of rice,it is suggested that the sowing time of rice in Southern Henan should be from April 30 to May 15,which is most conducive to improving and stabilizing indica rice quality.