Studies On Heritance Of Main Agronomic Traits And Their SSR Molecular Markers Based On Genetic Populations Of Tartary Buckwheat (Fagopyrum Tataricum (L.) Gaertn.)

Tartary buckwheat is annual short-day herbsbelong in genus Fagopyrum of Polygonaceae.It grows in cooler climate environment,with the optimum temperature of about 25℃for germination and growth,has a short reproductive cycle and high resistance to adversity such as cold,infertile and drought.However,tartary buckwheat flowers are so small that its artificial sexual hybridization become very difficult,resulting in few progeny population reported.In this study,because of the agronomic trait differences,six buckwheat cultivars（lines）were collected as parents for making three crosses,namely,"Chimiqiao×Yunqiao 1"（A）,"Jinqiaomai2×Pinku 1"（B）,"Yi 324×Yi 63"（C）.Based on their F₂,F₃ genetic segregation populations,the inheritance pattern,heritability and correlation of the main agronomic traits were studied.Then SSR molecular markers and QTL single marker analysis for the 241 plants of"Jinqiaomai2×Pinku 1"F₂ population were made.The key results obtained in this study are as follows:（1）The 7 main agronomic characters of the 3 populations showed continuous distribution and quantitative character inheritance,and all the characters showed continuous variation trend.The coefficient of variation between grain number per plant and grain weight per plant was the largest in all combinations F₂ and F₃.The coefficient of variation of grain number per plant of F₂ ranged from 49.54%to 66.15%,that of F₃ ranged from 38.81%to 56.93%,and that of grain weight per plant of F₂ ranged from 52.16%to65.87%.The variation of F₂ per plant grain weight ranged from 40.1%to51.11%.The variation coefficient of 1000-particle weight is the smallest and the most stable.The variation range of 1000-particle weight is6.59%～12.32%for F₂ and 8.03%～12.06%for F₃.The variation coefficient of 1000-particle weight for B and C is lower than 10%.Three combinations of F₂and F₃ populations showed significant positive correlation among plant height,main stem branch,stem base diameter,grain number per plant and grain weight per plant.The generalized heritability and narrow heritability of the same agronomic trait were different in different cross populations.The agronomic trait with higher generalized heritability included grain number per plant（0.756）,grain weight per plant（0.751）and1000-grain weight（0.645）.It was followed by basal node number（0.526）,plant height（0.513）and main stem branch（0.481）.Grain weight per plant,1000-grain weight and plant height had little difference among populations（<0.50）.The agronomic traits with high narrowly heritability were plant number（0.630）,base segment number（0.417）,1000-grain weight（0.372）,grain weight per plant（0.270）,plant height（0.238）.（2）After DNA of parents and representative F₂ progeny plants about"Jinqiaomai 2×Pinku 1"population were used as a template for screening polymorphism primers from 561 pairs of SSR primers,96 pairs of primers were discovered with polymorphism between parents,and its polymorphism rate is 17.11%.Among them,37 pairs of primers were polymorphic between populations,accounting for 38.5%of the polymorphic primers.（3）PCR amplification was performed on 241 plants of F₂ population using 37 pairs of SSR primers,and a total of 214 bands were obtained,with an average of 5.78 bands per pair of primers,including 93 polymorphic bands,and the percentage of polymorphic bands was 43.46.（4）The chi-square test was performed on 37 polymorphic markers.9markers（24.32%）showed segregation bias,2 at p<0.05 level,accounting for 5.4%of the total markers;3 at p<0.01 level,accounting for 8.11%of the total markers;4 at p<0.001 level,accounting for 10.81%of the total markers.Seven markers were biased in favour of the mother,accounting for 77.78%of the markers separated,and two markers were biased in favour of the father,accounting for 22.22%of the markers separated.（5）By frequency analysis,seven agronomic traits,including plant height,number of main stem branches,basal diameter and number of grains per plant,were approximately distributed as a single-peaked normal distribution and showed a continuous distribution.Tat G0252 and Tat G0255 were detected to be significantly different from each other for several traits.Tat G0252 was detected twice,at plant height and at the main stem branches.Tat G0255 was detected three times,in the main stem division,the number of grains per plant and the grain weight per plant.