Molecular Identification of Cassava Mosaic Begomoviruses Associated with Cassava Mosaic Disease in the DR-Congo Using Primer Pairs.

Molecular analysis of cassava leaf samples from different regions of the Democratic Republic of Congo (DR-Congo) was conducted to identify cassava mosaic begomoviruses (CMBs) associated with cassava infections in farmers' fields in Gandajika (Eastern Kasai), Bas-Congo and Kinshasa. Four specific primer pairs M1F/M1R, M2F/M2R, Begomo 146/Begomo 672, and EAC4F/EAC4R were used to detect East African cassava mosaic virus (EACMV) AC2, African Cassava Mosaic Virus (ACMV) AC2, ACMV DNA-A, and EACMV-UG DNA-A AC4, respectively. Based on PCR analysis, only African cassava mosaic virus (ACMV) and East African cassava mosaic virus (EACMV-UG) were identified in the cassava growing regions. Overall, 67% of cassava samples were infected with ACMV, 10% with EACMV-UG, and 10% with both, ACMV and EACMV-UG. No virus was detected in 13% of symptomatic samples. Thus, although EACMV-UGG is present in targeted areas, ACMV remained the most common CMB in the DR-Congo.

African Cassava: Biotechnology and Molecular Breeding to the Rescue.

Cassava is an important African food crop, where it is a staple to about 250 Million people. It is a household name in Nigeria, the world largest producer of the root crop. It is propagated from stem cuttings and well known for its adaptation to wide range of adaphoclimatic conditions and including those unfavourable for other crops. However cassava production, exploitation, utilization and acceptance are limited by diseases and pests, cyanogenesis, low protein content and quality, and post-harvest physiological deterioration. The breeding research activities of IITA (International Institute of Tropical Agriculture) Ibadan, Nigeria, CIAT (International Centre of Tropical Agriculture) located in Cali, Colombia and National Root Crop Research Institute (NRCRI), Umudike, Nigeria have transformed cassava to double as a food security crop as well as a cash and industrial crop. Of recent, Bio Cassava Plus, an initiative sponsored by Bill and Melinda Gates, has been using experimental biotechnology approaches to address several of the main constraints to African cassava. This review presents the many advantages of cassava to the small-scale farmer and its potentials for industrial applications. It also describes the roles of biotic and abiotic factors hampering the production yield, root quality, nutritional adequacy, marketability and acceptance, and commercial processes. The use of conventional breeding and biotechnology in unravelling the milieu of these constraints is discussed as well.