Ensuring Genetic Purity of Pigeonpea Hybrids by Incorporating a Naked-Eye Polymorphic Marker in A and B Lines

Abstract

To enhance the productivity of pigeonpea (Cajanus cajan (L.) Millspaugh) a hybrid breeding technology, based on the cytoplasmic nuclear male-sterility (CMS) system and partial natural outcrossing, is currently been used. However, there are diffi culties to maintain genetic purity of the hybrids and their parents. The incorporation of an easily identifi able morphological marker (naked eye polymorphism (NEP)) could be used to determine seed purity. The morphological marker selected for this study, obcordate leaf, is not present in cultivated pigeonpea; it is inherited as a single recessive gene and can be observed soon after planting (approx. 6 wk). To incorporate the obcordate leaf shape into hybrid parents, the trait was transferred from the germplasm accession ICP 5529 into male-sterile (A lines) and the corresponding maintainers (B lines). The hybrids derived from crosses involving obcordate leaf A lines and normal leaf fertility restorers (R lines) were fully fertile and had normal lanceolate leaves; thus the difference between A line and hybrids was clear. The use of obcordate leaf as a NEP marker in pigeonpea would contribute to preserve parental line purity and confi rm hybrid status