Regeneration Characteristics And Effects Of Stubble Height On Yield And Quality For Different Rice Varieties

In order to screen out the varieties suitable for the breeding of ratoon rice in the middle of Hunan province and the suitable height for the breeding,The eight hybrid rice from different varieties.The experiment was carried out in Changsha,Hunan province,in 2016were used to study the difference of vegetative growth,reproductive growth,yield formation and rice quality between the main crop rice and the ratoon rice.Otherwise,stubble height of5 cm,15 cm,25 cm and 45 cm in all of HHZ,JLY751 and YLY were used to study the influence of the germination of regrowth,development,yield and yield composition,and rice quality formation.The main results showed as following:1.Significant difference of main crop rice and ratoon rice in different rice varieties were detected,the two seasons of fertility are 185d~212d.The fertility days of these rice varieties of were range from 132 days to 144 days.the longest and shortest fertility days of ratoon rice varieties were CLY755 and JLY1198,respectively,and their fertility days were68 days and 53 days,respectively.The total fertility of the rice varieties was positively correlated with the season of the main crop rice.(correlation coefficient was 0.95836).If the rice full heading of ratoon rice couldn't arrive before September 15,it will be existential normal mature harvest risk In Changsha,Hunan Province.2.Significant difference of yield in different varieties were founded,the yield of main crop rice was range from 456.9kg/667m~2 to 656.2kg/667m~2,and the yield of ratoon rice was range from 325.7 kg/667m~2 to 476.0 kg/667m~2,the total yield of the two seasons rice was 859.6kg/667m~2~1091.8kg/667m~2,the yield of JLY1198 is 859.6 kg/667m~2,and the yield of QLY1168 is 1091.8kg/667m~2.3.The difference of rice milling quality of first reason rice were significantly.the difference between first reason rice and regeneration rice of White rice rate was small,The main crop rice and ratoon rice varieties of the sperm rice rate was 65.0%~67.9%and 67.5%~69.5%respectively.The difference between main crop rice and ratoon rice in the varieties is obvious.the whole milled rice rate of 4001/HL was 69.9%,it's the highest.and YY390was 46.1%,it's the lowest.the highest and lowest whole milled rice rate of ratoon rice were68.3%and 65.7%,respectively,the difference of rice milling quality were not significantly.the average grain weight of main crop rice and ratoon rice was 56.5%and 67.4%,respectively,The difference of rice milling quality between main crop rice and ratoon rice were not significantly;The difference of length-width ratio of different varieties and two seasons rice are not significantly;The highest and lowest chalkiness grain rate of main crop rice was 63.8%and 24.3%,respectively,The highest and lowest chalkiness degree of main crop rice was 14.5%and 3.8%,respectively;The highest and lowest chalkiness grain rate of ratoon rice was 63.9%and 23.3%,respectively,The highest and lowest chalkiness degree of ratoon rice was 14.6%and 3.6%,respectively.These results indicate that the quality of ratoon rice was improved obviously compared with main crop rice.4.The growth period and yield of the ratoon rice were significant effected by stubble height,the period of duration was shortened with the increase of the height,but this trend were differently between the different varieties.The yield of JLY751 and HHZ reached the highest(408.7 kg/667m~2 and 313.5 kg/667m~2,respectively),when stubble height was 25 cm,and the yield of YLY9918 reached the highest(375.7 kg/667m~2),when stubble height was 35cm.