Construction of Molecular Linkage Maps Using SRAP Markers in Sweetpotato

Abstract

The objective of this study was to construct a linkage map of sweetpotato [Ipomoea batatas (L.) Lam.] based on Chinese cultivars with higher marker density than previous maps. Cultivars Luoxushu 8 (female parent) and Zhengshu 20 (male parent) with obvious differences in starch content, yield, β-carotene content, and disease resistance were crossed to produce a segregation population with 240 F₁ individuals. Among the total 800 sequence-related amplified polymorphism (SRAP) markers, 770 and 523 markers showed polymorphism in the female and male parents, respectively. Using the “double pseudo testcross” strategy, 2 linkage maps were constructed by means of JoinMap 3.0. The linkage maps were composed of 473 markers in 81 linkage groups for Luoxushu 8 and 328 markers in 66 linkage groups for Zhengshu 20. The former map covered 5802.46 cM with an average marker interval of 10.16 cM, and latter one covered 3967.90 cM with an average of 12.02 cM. Both linkage maps may facilitate marker-assisted selection, gene localization, and gene cloning in sweetpotato.