Development of a Genetic Linkage Map and QTL Analysis in Sweetpotato

AFLP;sweetpotato;genetic linkage map;QTL;resistance;RKN

Cervantes-Flores, Jim Carlos ; Bryon Sosinski, Committee Co-Chair,Craig Yencho, Committee Co-Chair,William Thompson, Committee Member,Zhao-Bang Zeng, Committee Member,Cervantes-Flores, Jim Carlos ; Bryon Sosinski ; Committee Co-Chair ; Craig Yencho ; Committee Co-Chair ; William Thompson ; Committee Member ; Zhao-Bang Zeng ; Committee Member

University:North Carolina State University

关键词: AFLP;    sweetpotato;    genetic linkage map;    QTL;    resistance;    RKN;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/5679/etd.pdf?sequence=1&isAllowed=y

美国|英语

来源: null

【 摘 要 】

Despite its worldwide importance, sweetpotato [Ipomoea batatas (L.) Lam] genetic research lags behind that of other major crops. To address this issue, we developed a genetic linkage mapping population consisting of 240 individuals of a cross between 'Beauregard' (a leading orange-fleshed US sweetpotato cultivar) and 'Tanzania' (a cream-fleshed African landrace). A total of 1751 ('Beauregard') and 1944 ('Tanzania') AFLP markers were located and framework maps consisting of 726 and 947 single-dose AFLP markers were ordered into 90 and 86 linkage groups for 'Beauregard' and 'Tanzania', respectively. Multiple-dose markers were used to identify homologous groups, allowing the assignment of the linkage groups to 15 homologous groups for each parental map. Only few linkage groups remained unassigned. The mapping population was phenotyped and quantitative trait loci (QTL) identified for important traits using single-point and interval mapping procedures. Resistance to root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood], a worldwide pest, in the progeny was assessed. QTL analyses revealed seven significant QTL in 'Tanzania' and two in 'Beauregard'. In 'Tanzania', QTL with negative and positive effects on resistance were observed, each explaining approximately 20% of the observed variation. In 'Beauregard', two QTL that increased resistance explained approximately 6% of the observed variation. Based on molecular and phenotypic data, RKN resistance is hypothesized to be conferred by several genes, but at least nine loci (7 from 'Tanzania' and 2 from 'Beauregard') had the biggest effect.Genetic analyses of dry-matter, starch, and beta-carotene content and storage root yield were also conducted. Several QTL ranging from 8 (beta-carotene) to 18 (yield) were identified that affected these traits, and their importance in their inheritance is discussed. Strong correlations were observed between carotene and starch content in the storage roots, and also between starch and dry-matter content. To our knowledge, this is the most complete genetic linkage map of sweetpotato available, and we report the first QTL mapping studies in sweetpotato for storage root quality traits. We anticipate that this research will have a great impact for the sweetpotato breeding community, providing a foundation for the use of molecular techniques in sweetpotato breeding.