| Peanut(Arachis hypogaea L.)is an important oilseed and cash crop in China.The production and consumption of peanut in China has ranked the first worldwide for many years,playing an irreplaceable role in ensuring national food security.However,aflatoxin contamination seriously affects the quality safety of peanut and their products,threatening consumers’ health and impeding the development of peanut industry.Cultivating and planting resistant varieties is the most economical and effective way to control aflatoxin contamination in peanut,but the genetic natures of resistance to Aspergillus flavus remains unclear,which has impeded the breakthrough of resistance enhancement.In this study,a recombinant inbred line(RIL)population constructed through crossing a resistant genotype J11 with a susceptible genotype Zhonghua 16 with high yield was used to identify novel recombinant lines with resistance to A.flavus infection and/or to aflatoxin production.Meanwhile,a genetic linkage map was constructed based on resequencing analysis.QTLs related to A.flavus resistance were detected by linkage analysis.The main results are as follows.1.Through the identification of infection resistance and aflatoxin production resistance of the 296 RILs for three years,the RIL population was found to have an average infection index of 80.84%,ranging from 52.93% to 99.65%,and an average aflatoxin content of 121.59μg/g,ranging from37.24μg/g to 336.77μg/g.Five infection-resistant lines and 12 aflatoxin production-resistant lines were identified.Among which,QT1068 was resistant to both infection(53.85%)and aflatoxin production(56.72μg/g).Combined with the previous identification results for pod size,a specific recombinant line(QT1028)with low aflatoxin content(54.39μg/g)and large pod(210.65g)was identified.This study preliminarily revealed the potential of integrating resistance to A.flavus and large pod.2.After screened the sequenced markers of RIL population and its parents,a high-density genetic linkage map with a length of 1573.85 c M was constructed by using the MPR package.The average bin interval of the map is 0.58 c M,which contains 233365 markers(213622 SNP and 19743 In Del)and is divided into 2802 bins.A sub-genome is 760.69 c M long with 1257 bins,B sub-genome is 813.16 c M long with 1545 bins.The length of linkage groups(LGs)varied from 57.28 c M(A06)to 96.64 c M(A09).The map could provide strong support crucial reference for QTL mapping of resistance to A.flavus and other important agronomic traits in peanut.3.The phenotypic data of resistance to A.flavus and the genetic linkage map were combined to detect QTLs by using Ici Mapping 4.2 software.A total of five QTLs related to infection resistance were detected with 5.03-10.87% of phenotypic variation explained(PVE)which were distributed on LGB03,LGA05,LGA08 and LGB10.QTL q PSIIB10 was consistently detected in three years with 9.94-10.58%PVE.A total of eight QTLs related to aflatoxin production resistance were identified with 5.21-9.77%PVE,which were distributed on LGA05,LGB02,LGB05,LGB06,LGB08 and LGB09.QTL q AFTA05.b with 4.64-8.13% PVE and q AFTB06.b with 6.27-7.62% PVE were repeatedly identified in two years.Through the analysis of QTLs related to infection resistance among RILs,four QTLs were found from J11 and one from Zhonghua 16,and two recombinant lines with infection resistance were found to possess five related QTLs.These results provide a useful foundation for peanut pyramiding breeding for resistance. |
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