Quality And Yield Formation Characteristics Of Noodle Rice And Their Response To Nitrogen Fertilization

Noodle rice is beneficial to structure and total production balance of grain,and meet people’s diverse needs of consumption,the main variety origin is early indica rice.Noodle rice is one of the effective methods that can solve the low economic value of early indica rice caused by it’s poor eating quality.At present,the quality and yield formation characteristics of noodle rice is unclear,it’s important to formation high quality and yield of noodle rice by research it’s quality and yield formation characteristics.In this text 19 early indica rice varieties planting in Hunan province were gathered to determine the relationship between rice quality and rice noodle quality;choose representativeness noodle rice（Luliangyou 996,Zhongzao 39,Zhongjiazao 17）and control check（Lingliangyou 268,Xiangzaoxian 42,Xiangzaoxian 45）as the materials,field experiments of variety comparison and nitrogen regulation were conducted,and determine the quality and yield formation characteristics and the effect of nitrogen fertilization on quality and yield of noodle rice.The main results were shown as following:（1）There were significant or extremely significant correlation between amylose content in rice and the broken rate（r=-0.679）,value of dissolving starch（r=-0.946）,acidity（r=0.886）,uniformity（r=0.565）of rice noodle.The change of broken rate of rice noodle with the change of amylose content in rice fitted the Density model,the rice can’t be processed into noodle when amylose content less than 13.4%,if the lowest amylose content in rice is 23.2%,the broken rate of rice noodle will be 0,when the dissolving starch≤15%,acidity≥200%,uniformity≥90%the minimum amylose content in rice were 22.5%,16.8%,20.6%,respectively,when the broken rate of rice noodle were 0,and 6 early indica rice were selected can suitable for noodle rice（Rongyou 233,Xiangzaoxian24,Guangluai 4,Luliangyou 996,Zhongzao 39,Zhongjiazao 17）.（2）The amylose content was significant higher in noodle rice than control check,the amylose content higher 2.1%-13.7%and lower 4.7%-21.9%planting in early season than planting in late season with noodle rice and control check,respectively.（3）Analysis the distribution of starch granules in noodle rice and control check,the noodle rice has higher and lower percentage of starch granules with smaller and larger diameter than control check,respectively.（4）As the ratio of amylose accumulation to grain weight,amylose content were determined by amylose accumulation,analysis the parameter of amylose accumulation,the maximum and the mean accumulation rate of amylose higher 24.9%-80.7%and 28.2-70.4%,respectively,the rate of amylose accumulation at gradual,rapid and slow stage higher11.3%-70.0%,23.5%-80.5%,23.1%-85.0%,respectively.The amylose accumulation when the maximum accumulation rate happened higher 60.2%-97.6%in noodle rice than control check,Amylose accumulation had the extremely significant positive correlation（R=0.999）with amylose accumulation at the start of the maximum accumulation rate.（5）Analysis the two pathways closest connection to the formation of amylose,there were 3 down-regulation proteins LOC＿Os01g62420.1、LOC＿Os02g36600.1、LOC＿Os08g37380.2in the glycolysis/gluconeogenesis pathway,one up-regulated protein LOC＿Os06g04200.1and two down-regulated DEPs LOC＿Os05g32710.1 and LOC＿Os04g43360.1 in the starch and sucrose metabolism pathway.The protein LOC＿Os06g04200.1 is important in granule-bound starch synthase,ADPG and UDPG can be catalyzed to formation amylose.（6）The panicles m^-2higher 8.3%-32.6%in control check than noodle rice,and the spikelets per panicle,setting percentage and grain weight were higher 5.2%-19.9%、3.8%-11.2%and 2.4%-6.4%in noodle rice than control check.The grain weight had the maximum contribution to yield of noodle rice and control check.The duration of gradual,rapid and slow stage of grain-filling mean longer 1.1d,0.8d,3.1d in noodle rice than control check,the time of the maximum grain-filling rate occurred delayed 1.5d in noodle rice than control check.（7）Reduction of nitrogen(120kg hm^-2),the amylose content increased significantly with LLY996,and an opposite trend with LLY268.And the same trend with dry matter weight at maturity.Reduction of nitrogen both LLY996 and LLY268,had lower panicles and spikelets,the N-content and N-uptake lower 5.2%-19.5%,5.7%-29.6%in straw and grain,respectively,and the N partial factor productivity,N use efficiency for grain production increased18.0%-24.5%,10.5%-13.3%,the difference are significant.In conclusion,the starch of noodle rice has the characteristics of has higher percentage of starch granule with lower diameter,and when the noodle rice has the lowest amylose content of 23.2%,the broken rate of rice noodle is 0.Analyzed the quality formation characteristics of noodle rice,the higher amylose content caused by the higher accumulation and accumulation rate of amylose in noodle rice,the 6 key proteins identified in“glycolysis/gluconeogenesis pathway”and“starch and starch and sucrose metabolism pathway”are benefit for amylose formation lead to higher accumulation and accumulation rate of amylose.The grain weight had the maximum contribution to yield of noodle rice,the longer duration of grain-filling is benefit for grain weight.Reduction of nitrogen lead to lower panicles,spikelets and lower yield,meanwhile it is benefit for increase amylose content in noodle rice.