Nursery and tree management practices for Improved germination, seedling quality and fruit Characteristics of cape st. Paul wilt disease Tolerant coconut varieties

Abstract

To meet the increasing demand for Cape St. Paul Wilt Disease (CSPWD) tolerant coconut seedlings, this research was carried out to develop interventions for improving seed nut germination and vigour, seedling quality and vigour and Sri Lanka Green Dwarf (SGD) fruit characteristics. Seven (7) different experiments were carried out to assess pre-nursery practices, seedling spacing and fertilizer application, ablation and fruit thinning towards addressing deficiencies in coconut nursery and tree management practices. Fully burying Sri Lanka Green Dwarf crossed Vanuatu Tall (SGD x VTI) coconut hybrid seed nut in decomposed sawdust at pre-nursery stage improved germination rate, speed of germination and germination index respectively by 33%, 30% and 98% relative to the control. A treatment combination of 60-cm triangular spacing and fertilizer application of 47.3:96.6:126.0:28.4 g seedling·1 N:P20S:K20:MgO produced good quality SGD x VTI coconut hybrid seedlings with averagely 34% higher vigour, 12% bigger collar girth, 11 % wider canopy diameter and 5% increase in height relative to the control. Thinning ofSGD coconut variety to 10 fruits per bunch increased crude protein and Vitamin C contents of fresh fruits by 31 % and 42% respectively; and average fresh fruit weight by 32% and its components: husk, shell, kernel and water averagely by 42%, 61 %, 42% and 65% respectively. Findings of prenursery studies are recommended for dissemination to appropriate entities to improve seed nut germination rate and increase supply ofSGD x VTI coconut hybrid seedlings to fanners. Further research is recommended for assessing field perfonnance of SGD x VTI coconut hybrid seedlings as affected by potassium nitrate soaking treatment, planting depth or nut size.