Association Analysis Of Flower And Pod Abscission Traits With SSR Markers In Northeast Spring Sowing Soybean

Soybean is the main source of plant protein, also is an important oil andeconomic crop, and it is irreplaceable in our country’s economy. In recentyears, with the improvement of people’s living, the demand of soybean alsoincreased dramatically. However, the production of soybean in China has adownward trend year by year, and China’s soybean output can not reach therequirement of the domestic market. Excessively leaning on the importedsoybean is a serious threat to the survival and development of soybeanindustry in China.As a result of the low yield of soybean and the poor benefits, theproduction of soybean was gradually declining in recent years. Therefore, toimprove the yield of soybean has become a necessary choice, which couldchange the passive situation of China’s soybean industry. In the process ofsoybean production, the high rate of flower and pod abscission is one of themost important factors which limited the production. In general, the abscissionrate of flower and pod is30%⁸0%. Experiments result and practice haveshowed that the potential of improving soybean yield is very large throughreducing the abscission rate of flowers and pod. The study on molecularmechanism of soybean abscission of flower and pod and creating newmaterials with high yield are very significant to improve the yield of soybean.There are many researches that have been conducted in the physiologicaland biochemical levels, and the QTL mapping on linkage group about soybeanabscission. However, the study of the gene regulation on flower and podabscission was relatively few. Elite SSR makers associated with the flower andpod abscission and other major agronomic traits in the northeast spring sowingsoybean, which consisting of104（2011） and314（2012） accessions weremeasured at flowering and maturation stage under the same field managementin Mudanjiang experimental locations, China. A total of205SSR makers distributing on the20linkage groups of soybean were utilized to genotype thetested materials. The linkage disequilibrium and the structure of the populationwere analyzed by TASSEL2.1and STRUCTURE2.3. The associationanalysis between SSR and flower and pod abscission rate was performed usingTASSEL GLM （general linear model） program with the Q value as thecovariate, aimed to screen out the loci with significant effects on the flowerand pod abscission of northeast spring soybeans. The main results aresummarized as follows:（1） Northeast spring sowing soybean has a lower genetic diversity. A totalof763alleles were identified on205SSR loci, and each locus had2-12alleles.The polymorphism information contents （PICs） of the SSR loci ranged from0.054-0.771.（2） The tested materials population could be clustered into two majorsubpopulations. The104materials of2011have2subgroups based on theresults of SSR maker genotyping; The314materials of2012have the samesubgroups. This result was consistent with the population structure ofstatistical description of flowers and pods abscission rate.（3） The level of linkage disequilibrium （LD） among intrachromosomalSSR loci is low. The majority of locus pairs in LD were23.37cM and2.62cM,2011and2012respectively.（4）33SSR loci were found to be significantly associated with flower andpod abscission rate on the205SSR markers. The results showed that, both in2011and2012, four SSR loci associated with the phenotype of flower and podabscission rate were detected, and they were mapped on the Satt534（B2）,Satt452（E）, Satt244（J）, Satt478（O）.2SSR loci were found to be significantlyassociated with flower and pod abscission related traits of104accessions in2011and2012, and they were mapped on the Sct₁99（I）, Satt244（J）.5SSRloci were found to be significantly associated with flower and pod abscissionrelated traits of314accessions with different plant density in2012, and they were mapped on the Satt273（E）, Satt049（I）, Satt381（K）, BF008905（O）,Satt653（O）.The results of this study are meaningful for the marker assisted selectionbreeding of northeast spring sowing soybean varieties with low flower and podabscission rate and high yield quality.