Some characteristics of the Sri Lanka Green Dwarf (SGD): a variety resistant to the Cape Saint Paul Wilt Disease of coconut

Abstract

The Cape Saint Paul Wilt Disease (CSPWD), a lethal yellowing-type disease, has decimated thousands of hectares of coconut plantations in Ghana. Eighteen years of field screening showed varying levels of tolerance/resistance to the disease. Out of 27 different types screened only the Sri Lanka Green Dwarf (SGD) has so far shown complete resistance. This has been considered a very major step in finding a solution to the disease. Following this, studies were conducted on selected palms of SGD to have basic knowledge about some agronomic parameters and to assess the possibility of using the acquired knowledge to plan for future SGD improvement programmes. Characters studied included rate of germination, flower, stem, crown and leaf morphologies. The local West African Tall (WAT) variety was used as a check. The monoecious inflorescence was observed to be completely autogamous, as contrasted with the WAT, which exhibited partial to complete allogamy. Though the inflorescence of SGD had fewer number of female flowers (mean = 24.5) as compared to that of WAT (means = 32.15) a higher proportion of the flowers (34.4%) were set as nuts, resulting in higher number of matured nuts/palm in SGD. Other important observations made on SGD included fragile leaf and bunch attachments, and more susceptibility to insect attack. The implications of these observations make SGD unsuitable for release as a straight variety. Rather, it is being exploited in hybrid seed production with other tolerant types.

JOURNAL OF THE GHANA SCIENCE ASSOCIATION Volume 2 No. 2 (2000) pp. 88-93