BREEDING FOR RESISTANCE TO ROOT (WILT) DISEASE IN COCONUT

摘要

Root (wilt) is a serious disease of coconut in Kerala. The disease affects 16 million palms and causes an annual loss of 968 million nuts. A comprehensive breeding programme for evolving resistant/tolerant variety to Root (wilt) disease was initiatedat CPCRI Regional station, Kayamkulam during 1987. In the midst of heavily diseased palms in the disease hot-spots, some disease-free and high yielding West Coast Tall (WCT) and Chowhght Green Dwarf (CGD) palms were found. Based on these observations, the following crosses were made-WCT x WCT (SeWInterse), CGD (SeWInterse) and CGD x WCT. Seedlings produced from these crosses are being utilized in the breeding programme and also for the production of parental materials for the establishment of nucleus seed gardens. Breeding programme also resulted in the development and release of three varieties viz. Kalpasree, Kalparaksha and Kalpasankara specifically for cultivation in the root (wilt) prevalent districts of Kerala. All the three varieties are found to be high yielding in the heavily diseased districts of south Kerala. Kalpasree is a dwarf variety whereas Kalparaksha and Kalpasankara are semitall. Kalpasree and Kalparaksha are resistant to root (wilt) disease where as the Kalpasankara is only tolerant to the disease. All the three varieties are suitable for cultivation for tendernut purpose. Cultivation of these varieties are expected to significantly increase coconut production and productivity in the root (wilt) prevalent tracts of Kerala. Management of Root (wilt) disease, in the long run, will most likely rely on the integrated management practices centred on the exploitation of sources of resistance to the disease.