Study On The Distribution Characteristics Of Tartary Buckwheat Seed Setting And The Accumulation Of Matter In The Process Of Grain Formation

Tartary buckwheat is a kind of grain crop with the same source of medicine and food,which has good nutritional value and health care function and is loved by a majority of people.Tartary buckwheat plants have more flowers,but the number of effective grains is less,and the number of withered flowers and grains is more.Thus,the seed setting rate is generally lower than 35%when it matures.Flowering and fruiting is the key to the yield of Tartary buckwheat,but the material basis and physiological changes of flowering and fruiting characteristics and effective grain formation are not clear at present.In this paper,the dynamic changes of flowers and grains during the whole growth period,material accumulation,distribution rules,filling characteristics and physiological changes of the seeds of Tartary buckwheat after anthesis were studied by pot and field experiments.The purpose of this study is to reveal the flowering and fruiting rules of different parts of Tartary buckwheat,the characteristics of matter transport,grain filling and their physiological basis in the process of grain formation,which can provide theoretical basis and technical support for high-yield cultivation and breeding of high-yield varieties of Tartary buckwheat,and provide reference for further research on the regulation mechanism of flowering and Fruiting of Tartary buckwheat from the physiological metabolism and molecular level.The main results are as follows:1.The flower bud formation and grain formation of different Tartary buckwheat varieties have the same characteristics.After the primary inflorescence formed 3-5 d,the flower buds formed on the inflorescence,and 5-8 d later,the primary grain formed.After budding,the accumulation dynamics of total flower,withered flower,withered grain and effective grain of the varieties with high and low seed setting rate showed the same characteristics.The total number of flowers showed a trend of"slow-fast-slow",while the number of withered flowers,withered grains and effective grains showed a trend of"slow-fast".The formation of withered flowers and grains occurred 45 and 51 days after anthesis.The number of withered flowers and withered grains in low seed rate varieties was significantly higher than that in high seed rate varieties,which was 26.51%-185.50%and 10.23%-152.24%higher.2.There are significant differences in seed formation rate and seed abortion rate among different seed setting rate varieties.The grain formation rate and seed setting rate of QK3were 7.42%and 26.16%higher than that of XQ2,but the seed abortion rate was 12.03%lower than that of XQ2,indicating that high seed grain formation rate and low seed grain failure rate were important characteristics of varieties with high seed setting rate.3.The grain filling process of Tartary Buckwheat conforms to the"S"growth curve,which can be fitted by Logstic equation(R²>0.99^**),but the grain filling parameters of different seed setting rate varieties are different.The 1000 grain weight and average filling rate of high seed setting rate varieties were 11.10%and 14.81%higher than those of low seed setting rate varieties,respectively,but the duration of grain filling?T?was 3.71 days less than that of low seed setting rate varieties.The time(T_max)required for the highest grain filling rate(R_max)of high seed setting rate varieties was 1.23d shorter than that of low seed setting rate varieties,and the rate was 18.38%faster than that of low seed setting rate varieties.The results showed that the varieties with high seed setting rate has stronger filling ability and the grain can accumulate more material per unit time.4.There were significant differences in dry matter accumulation and distribution among Different Buckwheat Varieties.The ratio of dry matter weight of roots,stems and leaves decreased,while that of grains increased.The percentage of main stem grain of high seed setting rate varieties was 14.91%higher than that of low seed setting rate varieties,while that of branch grain was 16.12%lower than that of low seed setting rate varieties.The average dry matter distribution rate of main stem and branch of high seed setting rate varieties was13.26%and 23.07%higher than that of low seed setting rate varieties.The results showed that the high seed setting rate varieties had stronger ability of material transport during filling period.5.The content of soluble sugar and starch in Tartary buckwheat grain increased gradually after anthesis?20-40 d?,while the content of sucrose decreased gradually.At the same time,the sucrose content of the varieties with high seed setting rate was higher than that of the varieties with low seed setting rate,which was 0.29%-25.99%higher than that of the varieties with low seed setting rate.But there was no significant difference between starch and soluble sugar content.The enzyme activities of SS and SSS of high seed setting rate varieties were higher than those of low seed setting rate varieties,which was 5.22%-11.62%and6.64%-12.47%higher,respectively.Correlation analysis showed that the weight of 1000grains was significantly positively correlated with 3 sugar contents and 2 enzyme activities,and the correlation reached 0.547-0.966,indicating that enzyme activity and sucrose content were the key to affect grain filling.