Linkage map development by GBS, SSR, and SRAP techniques and yield-related QTLs in pea

The knowledge of the genetic basis of yield-related traits provides useful information for pea (Pisum sativum L.) breeding. The aim of this work was to develop a genetic linkage map of pea using SRAP (sequence-related amplified polymorphism), SSR (simple sequence repeat), and SNP (single-nucleotide polymorphism) markers and to identify QTLs (quantitative trait loci) controlling yield-related traits. An F2 mapping population and their F2:3 families were derived from an initial cross between cvs. Explorer and DDR14. The F2 individuals were evaluated with SRAP, SSR, and GBS techniques, which proved to be efficient, generating a set of 872 polymorphic markers for linkage mapping. The resulting map consisted of 128 genetic markers distributed in 9 linkage groups (LGs), covering 655.5 cM. The length of the LGs ranged from 49.1 to 114.8 cM, with 8 to 26 markers. QTL detection was performed using the composite interval mapping (CIM) method. A total of 45 QTLs were detected through the generations and environments evaluated. All of them were major QTLs that explain more than 10% of the phenotypic variation. The comparison among QTLs detected in the F2 population and F2:3 families in the two environments allowed assessing the consistency of two QTLs for pod width. On the other hand, the analysis of previous works allowed the identification of a common region in LG 3 associated with seed weight in different crosses and environments.