Field Evaluation of Some Cassava Cultivars against the African Cassava Mosaic Disease in the Humid Forests of Cameroon

There is a considerable deficit in the annual production of cassava in Cameroon of about 31 million tons, and this has been mainly due to constraints related to pest attacks and most especially diseases like the African Cassava Mosaic Disease (ACMD). This study was therefore undertaken on three sites in the locality of Bityili (South Region of Cameroon), to determine amongst improved and local cassava cultivars those that provide resistance to the development of the ACMD. The severity and incidence of this disease was evaluated and its impact on cassava yield. In each site, cassava was grown in a randomized complete block design. The local cultivars (Ekobele and Ngon kribi) showed higher severity (76-100%) and incidence of ACMD compared to the improved cultivars (TMS 92/0326 and TMS 96/1414) of 0-25% and 0-10%, respectively. Strong inverse correlations were observed between ACMD severity and yield performance, measured in terms of number of tubers/plant and weight of fresh tubers. The improved cultivars, TMS 92/0326 and TMS 96/1414, could, therefore, be recommended for large-scale planting in a bid to promote cassava production in the South Region of Cameroon.

Efficacy of Three Local Plant Extracts as Seed Treatment on the Germination, Infection and Vigour Index of Two Cotton Seed Varieties from Chad.

Seed treatment protects the seed or young plant against pests and diseases transmitted by seed or soil and stimulates germination and plant growth. Extracts from three Chadian plants, prepared from leaves of Azadirachta indica and bark of Boswellia dalzielii and Cassia sieberiana were evaluated for their efficacy as seed treatment on two varieties of cotton seeds; Stam F and A51 in Petri dishes and plastic trays. Cotton seed were soaked separately for one hour in various concentrations of aqueous and ethanolic extracts and plated on blotters as well as in sterilized soil in plastic trays. The results showed that seed treated with leaf extracts of Azadirachta indica and bark of Boswellia dalzielii reduced significantly (P ≤ 0,05) seed borne infection, improved seed germination and vigour index of cotton seeds when compared to those treated with Cassia sieberiana bark extract and distilled water. It can be suggested that extracts of A. indica and B. dalzielli have antifungal effect and can be used to treat seed against seed borne pathogens of cotton, increase seed germination and vigour index.