Analysis Of Quality Traits For Major High-quality Wheat In Gansu Province And QTLs Mapping Of Quality Traits From Landrace Heshangtou

Quality characteristic analysis is the foundation of wheat quality breeding. The highmolecular weight glutenin subunits(HMW-GS), starch granules properties, yellowpigment content and the1B/1R translocation are the major factors which influence thewheat quality. In this study, the above factors of the wheat quality were analyzed to knowthe distribution of these genes in wheat varieties of Gansu, and to provide theoreticalfoundation for accelerating the process of wheat quality improvement and quality breeding.The results provide:1. HMW-GS in endosperm from forty-three spring wheat cultivars werecharacterized with SDS-PAGE. Some allelic mutations were detected in clouding threealleles (Null,1and2*) at the Glu-A1locus, six alleles (7+8,17+18,22,7,7+9and14+15)at the Glu-B1locus, four alleles (5+10,2+12,2+11and2+10) at the Glu-D1locus. For theGlu-A1locus,21cultivars (48.84%) had the allele Null and1, excepted for Ganmai11that detected allele2*. At Glu-B1locus,25cultivars (58.14%) contained the7+8subunit,and there were18cultivars (41.86%) with the subunit5+10and2+12at the Glu-D1locus.Comprehensive analysis with three loci in Glu-1showing that high frequencies of Null,7+8,2+12were found in10cultivars (23.26%), but excellent subunit combinations (1,7+8,5+10) and (1,17+18,5+10) were presented only in8cultivars (18.6%). The lowfrequences of HMW-GS and their subunit combinations were the main reasons forresulting in lower processing quality in spring wheats in Gansu.2. For the starch properties of four wheat varieties with different quality, the totalstarch content in Ningchun4was the highest value among the cultivars, but Ganchun20had the lowest starch content. The Amylose content was the highest in Ningchun4, and thelowest in Heshangtou. The amylopectin content was the highest in Heshangtou, and thelowest in Ganchun20. The ratio value of Amylose/amylopectin ratio in Heshangtou hadlower value than other three cultivars, and had higher Amylose/amylopectin ratio thanother three cultivars. A-type starch granules of four varieties showed the shape of theoblateness which enhanced with the diameter increasing. The shapes of B-type granuleswere different with the varieties. The sphere granules were found in Heshangtou,Ganchun20and Ningchun4, while the irregular ones in Wuchun121as a result of easilybeing broken. The largest and the smallest in diameter for A-type granules wererespectively found in Heshangtou and Ganchun20while for B-type granules in Wuchun121and Ganchun20.3. In this study, locus specific molecular markers for high molecular weight gluteninsubunits of Dx5、Bx7、By8and By9, PSY,1B/1R translocation genes were used tocharacterize33spring wheat varieties to know the distribution of these genes in wheatvarieties of Gansu province, and provide parent materials in molecular marker-assistedbreeding of wheat with good quality. The results showed that, the frequency of cultivarswith genes of Dx5, Bx7, By8, By9and1B/1R translocation were60.61%,69.70%,51.52%,45.45%and42.42%. The proportion of the allelic variations of Psy-A1a and Psy-A1b atPsy-A1loci in these varieties were78.79%and21.21%. The proportion of the allelicvariations of Psy-B1a and Psy-B1b at Psy-B1loci in these varieties were75.76%and24.24%. The frequencies of allelic combinations Psy-A1a/Psy-B1a, Psy-A1a/Psy-B1b,Psy-A1b/Psy-B1a, Psy-A1b/Psy-B1b were54.55%,24.24%,21.21%and0. The number ofcultivars with high yellow pigment content (Psy-A1a/Psy-B1a) in Gansu were the biggest.Generally, the frequency of single good quality gene was high, the combination of goodquality genes were low and the number of cultivars with high yellow pigment content washigh in spring wheat cultivars released in Gansu province. Respectively, none weredetected without1B/1R translocation and with all the loci of Dx5, Psy-A1b, Psy-B1b.4. Based on the analysis of single agronomic characters and the near-infrared test ofgrain qualities, the cross combination Wuchun1×Heshangtou showed large variation in F2,indicated of the strong representatives of quality character QTL in this study.12QTLsdetected in this study were QTL-P-gau-1A, QTL-P-gau-6A, QTL-P-gau-2A,QTL-P-gau-4A, QTL-WG-gau-4A, QTL-WG-gau-3D, QTL-TW-gau-2A.1,QTL-TW-gau-2A.2, QTL-Z-gau-3D, QTL-Z-gau-5D, QTL-ST-gau-2A and QTL-ST-gau-5D.These were found to be correlated with5quality characters including protein content, wetgluten content, volume weight, Zeleny sedimentation value and dough stability time. Thelocus QTL-P-gau-2A, QTL-TW-gau-2A and QTL-ST-gau-2A located similarly betweenprimer Xgwm312and Xgwm526and were correlated with some quality characters such asprotein content, volume weight and dough stability time, indicating that these three locuswere the same gene.