An integrated genetic linkage map of Bixa orellana L.

Abstract

Bixa orellana L. is a plant from the Bixaceae family commercialized for its high bixin contents. Recently, demand for this pigment has led to the development of strategies for its genetic improvement. Through molecular markers obtained by sequence-related amplified polymorphism (SRAP), one β-cyclase marker and the two-way “pseudo-testcross” strategy an integrated genetic linkage map of Bixa orellana L. has been developed. Genetic maps were constructed for each parent and an integrated map using an F1 population with 157 individuals was produced. A total of 167 markers were used in linkage analysis. The maternal map covers a length of 306 cM, consisting of 52 markers with an average distance between them of 13.21 cM, distributed over seven linkage groups. The paternal map covers a length of 509 cM, consisting of 70 markers with an average distance between them of 12.28 cM, distributed over 12 linkage groups. The integrated genetic map covers a length of 879.054 cM, comprising 103 markers (102 SRAP and the β-cyclase), of which, 68% segregated in a 1:1 ratio and 32% in a 3:1 ratio, with an average distance of 14.6 cM between them, and distributed over 20 linkage groups. The size of the B. orellana genome was estimated between 1514 and 1728 cM. This study provides a basis for future construction of a high-density map and for genomic studies of B. orellana, in relation to bixin production and fruit dehiscence. It will also be useful in marker-assisted selection (MAS) within breeding programs of B. orellana and other species.