| Equal emphasis on high yield and high quality has become an inevitable requirement for the sustainable development of our country’s rice industry,as well as a long-term goal for rice variety improvement.The production and consumption of high-quality rice has become the main goal and direction of my country’s rice development at this stage.Cooking and eating quality are the most important quality traits in the process of rice consumption and the most concerned by consumers,as well as the most critical indicators for rice quality improvement.The determining mechanism and influencing factors of rice cooking and eating quality are relatively complicated,and the research is relatively weak,there are many unclear points,and there is a lack of clear control and improvement methods.At present,there have been many studies on rice cooking and eating quality from the perspective of endosperm starch,and the conclusions are relatively clear.However,there are relatively few studies on the relationship between rice protein and eating quality,and it is difficult to evaluate the effect of protein on rice eating quality.In this study,representative indica and japonica cultivars with different types of rice eating quality were selected.By changing the nitrogen nutrition status and external environmental conditions of the plants during the grain setting period,the changes in protein and quality of different rice varieties were observed,and the protein accumulation of different quality types of rice was further analyzed.And the difference in nitrogen metabolism,to explore the influence of rice protein accumulation behavior on rice quality,and further observe the changes of protein content and nitrogen metabolism pathways under environmental stress conditions,and analyze the response characteristics of different eating types of rice varieties to environmental conditions.The main test conclusions are as follows:1.There is a close relationship between rice protein content and rice quality,and there are differences in performance between indica and japonica subspecies.In terms of processing and appearance quality,the increase in rice protein content deteriorates the processing quality of indica rice,while the processing quality of japonica rice is improved,but the appearance quality is deteriorated to varying degrees;in terms of the physical and chemical properties of starch,the protein content of indica rice is increased The amylose content decreases and the gel consistency becomes shorter;in terms of cooking quality,the increase in protein content deteriorates the viscosity of starch,which is manifested as a decrease in the disintegration value and an increase in the reduction value,which is more pronounced in indica rice;in the taste In terms of quality,regardless of the subspecies of Indica and Japonica,the increase in rice protein content significantly deteriorates the eating quality of rice.2.The content of four protein components in rice showed the order of gluten>gliadin>globulin>albumin,and the indica and japonica varieties showed the same performance.Except albumin,the content of the three protein components was significantly or extremely significantly negatively correlated with the eating quality of rice.It shows that gliadin,globulin and gluten all have a bad effect on the taste of rice,and the negative effect of globulin and gliadin is more obvious in japonica rice,and the negative effect of gluten cannot be ignored.3.The accumulation rate of grain protein showed a trend of fast and slow,and the performance of indica and j aponica subspecies was consistent.The protein accumulation rate of poor-tasting japonica rice was significantly faster in the early stage than in the middle and late stages,while the protein accumulation of high-quality japonica rice grains was faster in the middle and late stages,and the accumulation rate remained relatively stable throughout the fruiting period.Indica rice performed the opposite.The activities of GS,GPT,and GOT at different grain positions during the grain setting period continued to decrease,and the decreasing amplitude showed a trend of faster and slower before and after,and the activities of the three were lower in high-quality edible materials.The soluble protein content of grains and flag leaves showed a single-peak curve change,reaching a peak around 17 days after heading,while grain protein accumulated fastest at 10-20 days after heading,indicating that around 17 days after heading is the key period for grain protein synthesis and accumulation.4.The protein content of rice under the treatment of low light stress during the grain setting period increased significantly,and the effect on the better-tasting materials was less than that of the poorly-tasting materials.In poor-tasting varieties,low-light stress makes the increase of gluten greater than gliadin,and the ratio of gluten to alcohol is basically unchanged or increased;in the varieties with better eating-tasting,low-light stress causes the increase of gliadin to be greater than gluten,The ratio of sugar to alcohol drops.The high temperature stress treatment during the grain-setting period also increased the protein content of rice significantly,and had a greater impact on the better-tasting materials.Indica rice has a greater increase in globulin,and japonica rice has a greater increase in gluten.5.Field test results show that currently cultivated high-yield and high-quality japonica rice varieties are mostly large panicles.In terms of material production characteristics,the dry matter accumulation of high-yield and high-quality varieties has no significant advantage in the early stage,but the ability of dry matter accumulation in the middle and late stages is strong,and the rate of stems and tillers is high.In terms of nitrogen accumulation characteristics,high-yield and high-quality varieties have low nitrogen accumulation in grains and plants,but high nitrogen harvest index,low nitrogen content in grains,and low protein content,which makes rice quality better. |
PDF Full Text Request