| Wild soybean(G.soja)is the wild relative species of the cultivated soybean(Glycine max(L.)Merr.).Wild soybeans and domesticated soybeans hybridize with ease,and fertile hybrids can be obtained.Wild soybean with richness of high yield,high quality,high resistance genes,and genetic diversity,is resources for soybean improvement breeding.Soybeans primary origin center is in China.There are abundant wild soybean resources in China.At present,wild soybean resources are facing the risk of extinction.In recent years,the rapid development of genetically modified soybean,is also potential risks to wild soybean resources.High yield is the major breeding objective in soybean(G max).The narrow genetic base of cultivar soybeans,as in other crops,is a bottleneck for high yield breeding,and this tendency is becoming more serious.Therefore,Exotic germplasm.such as wild soybean(G.has been investigated to broaden soybean’s genetic base and to find new alleles not present in common cultivars for genetic improvement.The first objective of this study was to analyze the hybrid rate of the cross between wild soybean and genetically modified soybean with resistance to glyphosate,the inheritance mechanism of transgene into the wild soybean and fitness of hybrids between wild soybean and genetically modified soybean with resistance to glyphosate,in order to provide scientific experimental data and theoretical support for the protection of the wild soybean.The second objective of this study was to construct interspecific population,map the yield related traits and gain stable QTLs with the positive alleles from wild soybean,in order to provide theoretical basis for identification on excellent genes of wild soybean,broadening the genetic basis of cultivated soybean and molecular marker assisted breeding of soybean yield.The third objective of this study was to optimize QTLs using meta-analysis method for identification of candidate section and local association analysis and the next candidate genes association analysis.The main results were as follows:1.The hybridization experiments were conducted between wild soybean and genetically modified soybean with resistance to glyphosate D04001 and D05001 respectively in 2004 and 2005.The results showed the artifical hybridization between wild soybean and genetically modified soybean with resistance to glyphosate was successful.Podding rate is from 3.4 to 10.7%in 2004,from 2.0 to 14.2%in 2005,F1 hybrids showed favorable glyphosate-resistance and were fertile.Offspring could be got.F2 generation preliminarily showed a normal 3:1 Mendelian segregation with spraying and quantitative PCR.2.Seven agronomic traits of F1,F2,and female wild soybean were measured:plant height,main stem branch number,shriveled pods number,pods per plant,seed weight per plant,seed number per plant,and 100-seed weight.Relative fitness and composite fitness of hybrids and female were analyzed by t-test.Under the conditions of glyphosate pressure,relative fitness and composite fitness of F1 hybrids derived from wild soybean and D04001 were higher than wild soybean,relative fitness and composite fitness of F2 hybrids carrying glyphosate-resistance gene were higher than F2 hybrids without glyphosate-resistance gene and wild soybean.Fitness of hybrids was affected by glyphosate-resistance gene EPSPS.In the absence of glyphosate.in addition to(Jiangpu wild soybean-3 × D05001)F1 hybrids,F1 hybrids derived from crosses between 4 wild soybeans(ZYD4196.ZYD4152,ZYD4157 and Jiangpu wild soubean-5)and D05001 compared with wild soybeans,relative fitness of shriveled pods number,seed weight per plant,100-seed weight was hicyher than wild soybeans,relative fitness of plant height,main stem branch number,pods per plant,seed number per plant was lower than wild soybeans,composite fitness of four crosses was higher than wild soybeans.F2 hybrids derived from the cross between Jiangpu wild soybean-5 and D05001 carrying glyphosate-resistance gene compared with F2 hybrids without glyphosate-resistance gene,relative fitness and composite fitness of seven agronomic traits were no difference.By contrast,relative fitness of shriveled pods number,seed weight per plant,100-seed weight of F2 hybrids,F2 hybrids carrying glyphosate-resistance gene.F2 hybrids without glyphosate-resistance gene was higher than Jiangpu wild soybean-5,relative fitness of plant height,main stem branch number.pods per plant,seed number per plant of F2 hybrids,F2 hybrids carrying glyphosate-resistance gene,F2 hybrids without glyphosate-resistance gene was lower than Jiangpu wild soybean-5,composite fitness of F2 hybrids,F2 hybrids carrying glyphosate-resistance gene,F2 hybrids without glyphosate-resistance gene was significantly higher than Jiangpu wild soybean-5.3.One F2 population(316 plants)derived from a cross between Jiangpu wild soybean-5 and cultivar soybean line D05001 was used to construct a genetic linkage map by JoinMap 3.0.In total,210 markers(207 molecular markers and 3 morphological markers)were mapped.The constructed linkage map covered 2205.85 cM and consisted of 24 linkage groups(LGs),with an average distance between markers of 11.09 cM.EPSPS gene was located on D1b linkage group by JoinMap 3.0,QTLs for seven traits were not linked to EPSPS gene by single marker analysis.4.Using the above constructed linkage map,seed and pod traits of F2:3,F2:4 and growth period traits of F2,F2;3,F2:4 were mapped by CIM and MCIM.41 QTLs for seed and pod traits and 36 QTLs for growth period traits were detected by CIM.24 additive-dominant QTLs and 15 pairs of epistatic QTLs for seed and pod traits and 15 additive-dominant QTLs and 9 pairs for epistatic QTLs of growth period traits were detected by MCIM.The phenomena,which were "QTL cluster" and "QTLs interaction network",were found in this study.22 QTLs were stably idetected in different generations and in different years.There were eight QTLs:qEPP-H-1,qEPP-Lb-1,qPP-H-1,qPP-Lb-1,qSWP-Lb-1,qWGP-B1-1,q WGP-H-1,and q VP-H-1,with positive effects from wild soybean.5.Eight QTLs in this study and QTLs for yield related traits in previous studies were meta-analyzed by the software BioMercator2.1.13 real QTLs were obtained,two QTLs on LG B1,one QTL on LG H,and ten QTLs on LG L.The meta-analysis was used to narrow down the confidence interval.Map distance ranged from 0.81 to 12.09 cM.There were two QTLs whose positions were 52.76 cM and 80.43 cM on LG L respectively,their map distance were less than 1 cM. |
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