Participatory approach of preferred traits, production constraints and mitigation strategies: implications for soybean breeding in Guinea Savannah zone of Ghana.

Soybean production is concentrated in the Guinea Savannah agro-ecological zone of Ghana. However, its cultivation is plagued with a number of constraints leading to low yields. A participatory approach was, therefore, used to identify farmers' and processors' preferred soybean traits and production constraints, climate change effects and strategies employed for mitigating these effects in three districts within the soybean growing areas in Northern Ghana. The study revealed that 72.0 % and 68.8 % of farmers in the Tolon and Savelugu districts, respectively, used improved soybean seeds for planting their fields. Over 13.0 % of farmers indicated late maturity as the most important constraint, followed by manual threshing difficulty and terminal drought which results in low grain yield and poor quality. About 70.0 % of farmers opined that climate change effects are causing obvious shifts in the rainfall pattern. Majority of the farmers (94.6 %) indicated that the onset of peak rainfall has changed in the past decade. Almost 44.0% of farmers also indicated that severe drought has affected pods filling in the past. A third (33.3%) of farmers indicated that drought usually sets in at pod initiation. The farmers enumerated some of the effects of early cessation of the rainfall in soybean production as drying up of immature and green seed (28.3%), low grain yield (27.1%) and poor seed quality (22.1%). Some of the mitigation strategies employed by the farmers include early planting (40.0%) and mulching (25.0%) to retain soil moisture for enhanced growth of crops. The order of farmers' preferences new soybean varieties were shattering resistance (16.0%), high grain yield (14.0%), large seeds size (13.1%), and early maturity (11.8%), whereas processors preferred varieties with large seed size (30.6%), high protein content (28.7%), pest resistance (15.9%) and short cooking duration (12.7%). Both the farmers and processors indicated their willingness to pay more for seeds with the desired traits. These findings will aid soybean breeders in developing new varieties that possess desired traits preferred by both farmers and processors for increased soybean cultivation and utilization.

Genetic variability, heritability and correlation analysis among maturity and yield traits in Cowpea (Vigna unguiculata (L) Walp) in Northern Ghana.

Experimental studies were conducted to evaluate 16 advanced breeding lines of cowpea (Vigna unguiculata (L) Walp) for genetic variability, heritability and correlation between maturity and yield related traits. The genotypes exhibited significant (P < 0.05) differences for the eight traits evaluated viz., number of days to 50 % flowering, number of days to 90 % pod maturity, plant height at maturity, number of pods per plant, number of seeds per pod, pod yield, grain yield and hundred seed weight. SARI-3-11-100, SARI-6-2-6, SARVX-09-004 and IT07K-299-6 had grain yields of 1.99 ± 0.30, 1.88 ± 0.20, 1.95 ± 0.30 and 1.91 ± 0.20 t/ha, respectively, which were significantly higher than the check (Songotra) (1.68 ± 0.01 t/ha). In addition, SARI-5-5-5 matured significantly earlier than the check but no significant difference was observed for grain yield. The higher value of phenotypic component compared to the corresponding genotypic component for all the traits suggest that there was an environmental influence on the performance of the genotypes. Hence, the need for multi-location evaluation of the promising lines for onward release if found stable. The information provided in this study, can be exploited in cowpea breeding program.

Efficacy of a cry1Ab Gene for Control of Maruca vitrata (Lepidoptera: Crambidae) in Cowpea (Fabales: Fabaceae).

Cowpea [Vigna unguiculata (L) Walp.] is an important staple legume in the diet of many households in sub-Saharan Africa. Its production, however, is negatively impacted by many insect pests including bean pod borer, Maruca vitrata F., which can cause 20-80% yield loss. Several genetically engineered cowpea events that contain a cry1Ab gene from Bacillus thuringiensis (Bt) for resistance against M. vitrata were evaluated in Nigeria, Burkina Faso, and Ghana (West Africa), where cowpea is commonly grown. As part of the regulatory safety package, these efficacy data were developed and evaluated by in-country scientists. The Bt-cowpea lines were planted in confined field trials under Insect-proof netting and artificially infested with up to 500 M. vitrata larvae per plant during bud formation and flowering periods. Bt-cowpea lines provided nearly complete pod and seed protection and in most cases resulted in significantly increased seed yield over non-Bt control lines. An integrated pest management strategy that includes use of Bt-cowpea augmented with minimal insecticide treatment for protection against other insects is recommended to control pod borer to enhance cowpea production. The insect resistance management plan is based on the high-dose refuge strategy where non-Bt-cowpea and natural refuges are expected to provide M. vitrata susceptible to Cry1Ab protein. In addition, there will be a limited release of this product until a two-toxin cowpea pyramid is released. Other than South African genetically engineered crops, Bt-cowpea is the first genetically engineered food crop developed by the public sector and approved for release in sub-Saharan Africa.