Research On Growth And Yield Characteristics Of Ratooning Rice From Low Nodes Under Different Stem Nutrition Conditions

Two hybrid rice combinations-Longliangyou072,Shenyou9576was adopted in this study, and three main crop conditions was set after harvest of the first season rice:natural regeneration condition(high stem height, all axillary buds of different nodes were kept);regeneration condition with axillary buds being cut(high stem height, only axillary buds from low nodes was kept);low stem height regeneration condition(low stem height, only axillary buds from low nodes was kept),yield formation and growth and development characters of low nodes ratooning rice in these three conditions were studied. The main results are as follows:1. Yield of ratooning rice under low stem height regeneration condition of Shenyou9576is the highest, and whole grain number per panicle,1000-grain weight and seed-setting percentage under this condition were higher than other two treats. Seed-setting percentage and1000-grain weight of low nodes ratooning rice under regeneration condition with axillary buds being cut were lower then low nodes ratooning rice under natural regeneration condition, which is not significant.2. Growth period differed between low nodes ratooning rice under different stem nutrition conditions.Growth period of ratooning rice under low stem height regeneration condition and regeneration condition with axillary buds being cut was significant later than ratooning rice under natural regeneration condition. Low nodes ratooning rice under low stem height condition performed the shortest time from booting stage to full heading stage, which was6days, while low nodes ratooning rice under regeneration condition with axillary buds being cut had a longer heading time, which was about10days.3. Low nodes ratooning rice under different stem nutrition conditions had different agronomy characters. Plant height, panicle length and total leaves of low nodes ratooning rice were not significant different between natural regeneration condition and regeneration condition with axillary buds being cut. Low nodes ratooning seedlings under regeneration condition with axillary buds being cut were significant higher than that under natural regeneration condition. Total leaves of low nodes ratooning rice under low stem height condition were significant higher than other two treats under high stem regeneration conditions.4. Leaf area index at the same growing stage of different treats showed the same trend:low stem height regeneration condition> regeneration condition with axillary buds being cut> natural regeneration condition. Leaf area index at full heading and mature stage of ratooning rice positively correlated with yield of ratooning rice.5. Flag leaf SPAD value of low nodes ratooning rice under regeneration condition with axillary buds being cut was significant higher than that under natural regeneration condition, and both reached a maximum at full heading stage, while flag leaf SPAD value of ratooning rice under low stem height regeneration condition reached its maximum at booting stage. Nitrogen translocation from stem and leaf to panicle of low nodes ratooning rice of the same variety under regeneration condition with axillary buds being cut was the biggest, which was60%to Longliangyou072and44%for Shenyou9576.6. Most flag leaf photothynthates of main crop at full heading stage transferred to panicle of main crop, and flag leaf photothynthates of main crop which was left in ratooning rice above-ground part at harvest time of ratooning rice was about3%.Content and output rate of nonstructural carbohydrates of low nodes ratooning rice stem under low stem height regeneration condition at heading stage were the biggest of these three different treats.