| Due to the high frequent utlization of a few key parents and long-term artificial selection and cultivation,genetic diversity among the cultivated wheat varieties is becoming increasingly narrow.The urgent breeding task is to broaden the genetic basis of wheat and enrich its diversity.In this study,the genetic diversity of 251 wheat germplasm resources at home and abroad based on agronomic,quality traits and molecular marker were analyzed,and the distribution of related traits in wheat germplasm resources was determined by molecular marker assisted selection(MAS),in order to enrich genetic diversity of wheat and select excellent breeding parents in Ningxia.1.The coefficient of variation of 251 wheat germplasm resources was from 14.25%to 41.77%in nine agronomic traits,in them,the numbers of tiller number(41.77%)and grain weight per spike(36.58%)were relatively large.The variation coefficient of nine quality traits ranged from 2.24%to 15.42%,and the numbers of sedimentation value and falling number were larger,they were 15.42%and 9.23%respectively.The genetic diversity index of agronomic and quality traits was from 1.87 to 2.10,with an average number of 1.96,and there were different degrees of correlations between every two traits.In a word,the variation range of wheat germplasm resources is large and their diversity is rich.2.The cumulative contribution rate of four principal components in agronomic traits was 86.554%,and No.1 to No.4 principal components were panicle related factor,production factor,thousand kernels weight factor and tiller number factor,respectively.The cumulative contribution rate of four principal components in quality traits was 89.023%,and No.1 to No.4 principal components were protein factor,water absorption factor,flouring factor and falling number factor,respectively.According to the D value ranking and field diseases resistance,7 excellent materials with comprehensive agronomic and quality traits and diseases resistance were screened,they were Secale cereale L.,Hongxinglong No.3,Jingzhou Rye,T.timopheevii Zhuk.,T.turanicum Jakubz,T.dicoccoides K(?)rn.,and MJ346,respectively.The 7 excellent materials were used as parents to construct successfully 12 hybrid combinations and 2 backcrosses.3.Based on agronomic and quality traits,251 wheat germplasm resources were culstered into four groups.Group Ⅰ～Ⅴ included 73,78,80 and 20 materials,respectively.Among them,group Ⅱwas the highest in the average kernels per spike(51.72 kernel),grain weight per spike(2.25 g),thousand kernels weight(40.63 g),water absorption(60.84%),falling number(431.47 s),volume weight(791.99 g·L-1)and hardness index(70.00),and the average moisture content(11.48%)was the lowest.Group Ⅳ was the highest in the average the tiller number(4.64 tiller),ear length(11.27 cm),spikelet number(21.37 spikelet),fertile spikelet(19.95 spikelet),crude protein content(17.56%),wet gluten content(37.50%)and sedimentation value(43.64 mL),which showed groups Ⅱ and Ⅳ were the comparatively excellent groups with more better agronomic and quality traits.4.A total of 242 alleles were detected by 51 pairs of SSR primers,with an average of 4.745 alleles,the ranges of effective numbers of alleles(Ne),Nei’s gene diversity index(H),Shannon’s information index(1)and polymorphism information content(PIC)were 1.103～1.808,0.089～0.447,0.181～0.639 and 0.097～0.862,the average value were 1.478,0.292,0.450 and 0.626,respectively.A total of 710 alleles were detected by 56 pairs of SRAP primers,with an average of 12.679 alleles,the ranges of Ne,H,I and PIC were 1.087～1.734,0.075～0.403,0.155～0.584 and 0.609～0.932,and the average were 1.342,0.212,0.340 and 0.831,respectively.251 germplasm resources were clustered into four groups by SSR or SRAP markers.The groups Ⅰ-Ⅳ by SSR markers included 86,84,50 and 31 materials,respectively.The groups Ⅰ-Ⅳ by SRAP markers included 86,63,88 and 14 materials,respectively.The same clustered results by the two molecular markers were group Ⅰ with the highest average ear length,kernels per spike,grain weight per panicle,flour yield and hardness index,and group Ⅳ with the highest average spikelet number,fertile spikelet,crude protein content,wet gluten content,water absorption and sedimentation value,which showed that the materials included groups Ⅰand IV contained excellent agronomic and quality traits.5.The distribution of molecular markers related on 8 agronomic,8 quality and 18 disease resistant traits in 251 wheat germplasm resources was clarified by MAS,and the distribution of excellent gene combinations in resources was also clear.Among them,the excellent gene combinations TaGS-D1a/TaGW2-6A-G/TaSus2-2BH/TaCwi-A1b of grain weight distributed into 2 materials.The gene combinations Pina-D1a/Pinb-D1a,Pina-D1a/Pinb-D1b and Pina-D1b/Pinb-D1a of grain hardness distributed into 91,77 and 62 materials,respectively.The gene combination TaZds-A1a/Psy-B1b associated with low yellowing content comprised 85 materials. |
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