Scope of novel and rare bulbiferous coconut palms (Cocos nucifera L.)

Abstract

A naturally occurring, rare bulbiferous coconut palm was identified at the Central Plantation Crops Research Institute, Regional Station, Vittal in Karnataka State, India, among West Coast Tall population. The palm produces only bulbil shoots in leaf axils in place of normal inflorescence. The identified palm happened to be twins in which one member was more vigorous than the other, but both of them produced only bulbil shoots instead of floral parts. Morphological and molecular studies on these palms revealed the main palm and their bulbil progenies are genetically uniform. The genetic uniformity of the twin mother palms and their bulbil progenies was confirmed through microsatellite analysis using 10 polymorphic SSR primer pairs specific to coconut and has been well demonstrated to differentiate coconut cultivars. The primary and secondary bulbil shoots were found to be capable of growing into independent plants making it possible to use them as propagules to develop a homogeneous clonal population hitherto unavailable in coconut. The bulbils showed axillary growth in 6–12th leaf axil which further again develop as secondary bulbils indicating the complete vegetative state of the palm. Comparison of shoot apices of a normal seedling with bulbil shoot revealed variation in cell growth pattern. Conservation of bulbiferous palms as a unique genetic resource needs to be taken up to utilize these rare sources for future breeding programmes, provided their seed-fertility can be restored.