Fruit component and seedling progeny analysis of komadan coconut types

Abstract

The present study was undertaken with a view to unravel the genetic status of a coconut type, Komadan, popular in the Central Travancore region of Kerala, in relation to its origin by comparing its three generations with WCT and NCD through fruit component and seedling progeny analysis. The study revealed that the Komadan types showed significant superiority for majority of the mother palm characters especially number of bunches and spadices and number of nuts per palm per year. Number of nuts per palm per year and number of female flowers per bunch had high heritability combined with moderate to high genetic advance indicating the predominance of additive genes. Among the Komadan palms, 33 per cent were of self pollinating nature thereby occupying a position in between WCT and NCD regarding pollination system. All the Komadan palms had nuts of different shades of brown while 70 per cent of WCT palm had nuts of green shade and NCD palms had varying shades of green, olive and brown nuts indicating the distinction of Komadan as a separate group. Komadan types were superior to WCT in all seednut characters except polar diameter of nut, oil content, thickness of husk and husk/nut ratio. It behaved as a distinct type regarding thickness of meat. One or the other of the Komadan generations was found to be on par with NCD for majority of the seednut characters. Komadan types occupied an area midway between NCD and WCT based on Niu kafa-Niu vai Introgression hypothesis with a clear progression through generations towards better weight of unhusked nut. Inbreeding depression was noticed in WCT and NCD as indicated by significant reduction in embryo and kernel weight in selfed nuts compared to open pollinated nuts. In Komadan there was no inbreeding depression indicating a high degree of homozygosity. The seednuts of Komadan types showed early germination compared to WCT and NCD. Regarding seedling characters, Komadan behaved as a distinct type for total leaf area over both WCT and NCD. Number of seedlings with split leaves was also more in Komadan. This type was superior to WCT for seedling vigour index also. Estimation of prepotency based on recovery of quality seedlings showed that 40 to 60 per cent of Komadan palms were prepotent where as the same in WCT and NCD were only about 20 per cent. Analysis of petiole colour of seedlings showed that 71 to 82 per cent of seedlings among the three Komadan generations showed moderates brown colour (bronze) ; 97 per cent of WCT seedlings had different shades of green and wider variations in petiole colour were noticed in NCD seedlings. It can be concluded that the Komadan type maintained its genetic identity over generations with respect to economically important characters viz. Kernel, copra, and oil content and also in the recovery of quality seedlings which inturn reflects its prepotent nature. The collection and maintenance of typical komadan germplasm through inter se crossing and development of isolated seed gardens for large scale production of komadan seedlings are suggested as future line of work.