Differential Analysis Of The Effect Of Different Panicle Type On Rice Yield And Quality Under High Nitrogen Input

For a long time,northern japonica rice represented by erect ears has high yield but relatively poor quality,and Japanese high-quality rice represented by curved ears has good taste and quality but relatively low yield.How to balance the synergistic development between yield and quality to ensure Improving eating quality under the premise of high yield of northern japonica rice is still a scientific problem that needs to be solved urgently,and it is worthy of further exploration.Therefore,in this experiment,two pairs of near-isogenic lines constructed from the typical erect panicle variety LG5 and Japanese curved panicle high-quality rice AKI were used as experimental materials.set up three treatments in high nitrogen H area（22.50g/m²）,low nitrogen L area（11.25g/m²）and control CK area（0g/m²）to study the photosynthetic production capacity and photosynthetic products of different panicle types of rice The main reasons for the high yield and low quality of erect ear rice were analyzed.The specific research results are as follows:The dry matter accumulation and photosynthesis of different panicle types of rice play an important role in the yield.Due to the shorter leaf length and lower leaf area index of rice with erect ears,the dry matter accumulation in stem sheaths and leaves of rice with ears with curved ears is higher than that of rice with ears with erect ears,but the dry matter weight of rice with ears with curved ears is significantly lower than that of rice with ears with curved ears.Erect panicles,with a small proportion of panicle,resulting in lower yields of curved panicle varieties.Due to its high stem-sheath transport rate,high chlorophyll content and net photosynthetic rate in leaves,high stomatal conductance and transpiration rate,and strong light and production capacity,erect panicle type rice promotes the formation of panicle grains and makes the panicle part significant.Increase,and ultimately promote a significant increase in the yield of erect ears.The yield of LG5 and its near-isogenic lines with erect panicle increased significantly under high nitrogen input.From the analysis of yield components,the reason for the increase in the yield of erect panicles mainly depends on the increase in the number of grains per panicle and the number of effective panicles,while the increase in the number of grains per panicle is mainly due to the increase in the number of grains in the middle and lower secondary branches,dominated by increasing the number of effective spikes.There was a very significant negative correlation between amylose content and taste value.The amylose content of the two panicle types of rice was significantly increased under high nitrogen input,and the amylose content and Fb₃ of erect panicle were significantly higher than those of curved panicle,and the Fa was smaller than that of curved panicle.Further determination of starch components in six different panicle positions showed that the two panicle types showed the highest amylose content in the upper part and the lowest secondary branch in the lower part.The increase in amylose content in erect ear rice was mainly due to the middle The increase of starch content in upper grains,curved panicle type rice mainly depends on the increase of grain starch content in the middle and upper primary branches.In general,the difference of amylose starch composition was mainly due to the difference of amylose content of upper secondary branch,the difference of Fb₃ of upper primary and secondary branches and the difference of lower secondary branch Fa.The taste value of erect panicle was significantly reduced under high fertilizer.The endosperm characters showed high AAC,Fb₃and protein content,and low Fa,which made the food taste components show negative changes.The poor starch composition of erect panicle led to the increase of rice hardness.The viscosity becomes smaller,the appearance and balance become worse,the disintegration value is small,and the cooling value is large,resulting in poor palatability.The grain weight gain of rice at different ear positions basically showed an"S"curve,and nitrogen input would reduce the grain weight of the primary and secondary branches in the lower part.The grain-filling rate decreased with the decrease of ear position,and the average grain-filling rate of erect ears was faster than that of curved ears;the grain-filling peak of primary branches was about a week earlier than that of secondary branches;under high nitrogen,the grain-filling of primary branches of erect ears was The velocity peak is shifted forward.In addition,the nitrogen accumulation,nitrogen physiological utilization rate and nitrogen fertilizer agronomic utilization rate in stems,leaves,sheaths and ear organs of erect panicle at maturity were significantly higher than those of curved panicle varieties.