Additive Main Effect and Multiplicative Interaction Stability Analysis of Grain Yield Performance in Cowpea Genotypes across Locations

Crops are largely influenced by climatic conditions during the growing season and therefore, minor deviation from optimal conditions can seriously threaten yield. In view of this, knowledge on the effect of environmental factors on crop growth and development could reduce the possibilities of significant yield loss. There have been statistical methods which have been developed in respect to characterizing crops but the additive main effect and multiplicative interaction (AMMI) method integrates analysis of variance and principal components analysis into a unified approach. AMMI has been used in the analysis of G × E interaction with greater precision in many crops. The objective of this study was to assess the extent of genotype x environment interaction and to select the stable cowpea genotypes in Ghanaian environments over seasons using AMMI model. Eight genotypes of cowpea released by Crops Research Institute of Ghana over two decades were selected for evaluation in two locations and two seasons using RCBD with 3 replications in forest and transitional zones of Ghana. When the mean yields of various genotypes were subjected to the AMMI model, the results showed that, a highly significant (P 0.001) genotype by location and by year interaction effects for cowpea grain yield was recorded with 63.1% of the total variation attributable to environmental effects. The AMMI Bi-plot of PC1 and GGE Bi-plot gave 80.8% and 89.3% respectively. Genotype Asontem (G3) had the highest yield and was adapted to all the environments and seasons. Genotypes Asetenapa (G1) and Soronko (G6) were however not stable with consistently low yield across all the environments. It is recommended that farmers in Forest and transitional zones of Ghana should cultivate the highly stable cowpea genotypes in order to get stable yields across environments due to climatic change.

Evaluation of Yield and Yield Components of Some Cowpea (Vigna unguiculata (L.) Walp) Genotypes in Forest and Transitional Zones of Ghana

Cowpea adapts very well to environmental conditions that normally affect production of crops such as drought, temperature changes and other environmental stresses. However, apart from these attributes, the growth and development of some cowpea genotypes especially during flowering stage and yield of some cowpea are affected by drought and high temperatures. Two field trials were conducted at two different locations (Mampong and Fumesua) in the 2015 and 2016 growing seasons to evaluate yield stability of eight cowpea varieties (Asontem, Tona, Nhyira, Videza, Asomdwe, Asetenapa, Soronko and Tona) released over two decades ago by CSIR-CRI in the forest and transitional zones of Ghana. The experimental design used was a Randomized Complete Block Design with three replications. The results revealed that Asontem, Tona and Nhyira had high yields in both locations and across seasons. Asontem showed superiority amongst the genotypes across the seasons and locations with Soronko and Asetenapa having the lowest yields. The growth and development of the cowpea genotypes especially during flowering stage and yield were affected by drought and high temperatures, hence Soronko and Asetena had low yields compared to Asontem and other genotypes. It is recommended that, for farmers to get more profit due to unpredictable climatic conditions prevailing in Ghana, it will be profitable to grow early maturing cowpeas such as Asontem that can be stable across different environments in order to get stable yields with good returns.

The Cry of “Sumampa”: A River in Mampong Ashanti in Crisis

The Sumampa River in Mampong-Ashanti in Ghana is a very important river that supplies water to the water processing company for treatment for the whole community and its environs. In spite of its importance, the buffer area of the river has been encroached by settlers. Residential houses sited along the river have channeled their waste water into the river and several anthropogenic activities go on along the river. Therefore, this study was conducted to assess the effects of anthropogenic activities on the quality of the river. Water samples were collected from various parts of the river including the source and outflow for physico-chemical and microbial analyses. The results showed that, the water was highly turbid with high total dissolved solids at some points because of intense anthropogenic activities. High turbidity and total dissolved solids greatly influence the microbial load of the water. We therefore recommend that measures are put in place to protect the Sumampa River through the creation of a buffer zone by planting trees along the banks of the river. The trees could help detoxify the run-off water that flows into the river.

Quality Assessment of River Offin along a Canopy Cover Gradient

The potential effect of canopy cover on the quality of River Offin which serves as drinking water for communities including Hwediem, Mprim and Boanim in the Mampong Municipality of the Ashanti region of Ghana was studied. These communities exemplify Ghanaian farming communities. Often, rural farmers do not have access to clean water. Using the part of the river serving these communities as a test case, we assessed the quality of water along a gradient of three different levels of canopy cover (closed, semi-closed and open canopy) where residents frequently access water. Physico-chemical tests showed that, the level of most of the physical and chemical properties of the water under all three different canopy covers was within the acceptable limits set by the World Health Organization. There was low turbidity where the canopy was closed resulting in relatively lower faecal coliforms. Total dissolved solids were also less where canopy cover was closed. Therefore, the general water quality could be potentially improved by planting trees along the river to form canopy.