Evaluation and selection of elite annatto (Bixa orellana L.) and identification of RAPD markers associated with yield traits

Abstract

Bixa orellana L. (annatto) is an economically important dye yielding plant. In the present study candidate plus trees (CPTs) of B. orellana on the basis of seed output and bixin content were identified from northern, central, and southern parts of Kerala state, India. Number of capsules per bunch, thickness of seeds and total bixin/g seed showed highly significant (P < 0.01) positive correlation to seed output. CPT-21 recorded maximum seed output (2.96 kg/year) and total bixin content (30.75 g/tree/year) and therefore designated as “plus” or “elite” tree. Variant specific RAPD bands were identified for annatto plants. Stepwise multiple regression analysis established significant association of 28 RAPD markers related to seed output and bixin yield/g seed. The validity of this selection of markers was further supported with discriminant function analysis. These markers could be of use in marker assisted selection and breeding programs in B. orellana. High genetic differentiation among CPTs was depicted in the dendrogram plotted from RAPD markers. The identification of elite trees with distinct genetic base will serve as source of planting material and also as parent plants for systematic scientific breeding for this crop.