Adaptability study of Cowpea [ Vigna unguiculata (L) Walp.] varieties in Pastoral areas of South Omo Zone, Southern Ethiopia

Field experiments were conducted on pastoral and agro-pastoral areas of South Omo Zone at Dasenech, Hammer and Gynagatom woredas of South Omo Zone, Southern Ethiopia on four cowpea [ Vigna unguiculata (L) Walp.] varieties in 2019 under irrigation. The objective of the study was to select the best performing cowpea varieties in the target areas. The cowpea varieties included in the field experiment were (Black eye bean, Bole, TVU, and Kankeit). The experiments were carried out using a randomized complete block design (RCBD) with three replications. The combined analysis of variance results depicted that there were significant differences among the varieties for all the studied parameters except the number of seeds per pod. The mean values for plant height ranged from 84.89 (cm) for the variety Bole to 120.67 (cm) for TVU. The mean values for the number of pods per plant ranged from 24.33 for the variety Bole to 46.90 for TVU. The mean value for 100 seeds weight was maximum (21.11g) for the cowpea variety black eye bean and, while it was minimum (17.11 g) for the variety TVU. The highest overall mean grain yield of 2457.0 kg ha - 1 was recorded for the variety Kankeit while the minimum 1695.3 kg ha -1 was noted for the cowpea variety black eye bean. Therefore, the variety Kankeit and TVU could be recommended for the study areas however further research should be done to put the recommendation on a strong basis. Cite this article as: Yoseph, T. 2022. Adaptability study of Cowpea [ Vigna unguiculata (L) Walp.] varieties in Pastoral areas of South Omo Zone, Southern Ethiopia. Int. J. Agril. Res. Innov. Tech. 12(1): 137-140.

Cowpea is a multipurpose crop; the entire plant can be used for either human or livestock consumption. Its major importance is to the livelihoods of millions of relatively poor people in less developed countries of the tropics. As suggested by Islam et al. (2006), all parts of the plant are used as food, which is nutritious providing protein and vitamins. Immature pods and seeds are used as vegetables while several snacks and main dishes are prepared from the grains (Pottorff et al., 2012). Cowpea grain contains about 25% protein and 64% carbohydrate and therefore has a tremendous potential to contribute to the alleviation of malnutrition among resource-poor farmers and can be used as animal feed and cash income. Its young leaves, pods and seeds contain vitamins and minerals, which have fuelled its usage for human consumption and animal feeding and the scorched seeds are occasionally used as a coffee substitute (Ogbemudia et al., 2010). As reported by Ayana et al. (2013) integration of cowpea with the prevailing farming system using native cowpea variety could have significant importance in improving soil fertility and productivity, improving feed quality and withstands the impact of climate change.
It is an annual legume grown throughout the semi-arid tropics, where it is valued and potential to produce high levels of fodder for livestock in addition to grain for people. Its dual-purpose character, weeds suppressing ability, positive impact on soil properties, drought tolerance and Int. J. Agril. Res. Innov. Tech. 12(1): 137-140, June 2022 being a warm-weather crop makes cowpea an attractive and promising forage species in a typical tropical lowland climate. It is usually better adapted to drought, high temperatures and other biotic stresses than other crop plant species (Hall et al., 2002;Tessema and Eshetayehu, 2006).
Drought stress related to climate change is a more challenge for enhancing agricultural productivity for resource-poor farmers. Cowpea is one of the dry land grain legumes for overcoming drought-related problems. Therefore, there is a need to introduce these improved cowpea varieties to moisture stress areas of the South Omo Zone under irrigation.

Treatments and experimental design
The experiment consisted of four improved cowpea varieties with a total of 12 plots. The field experiment was laid out in a randomized complete block design (RCBD) with three replications. Cowpea was sown in ten rows per plot with a spacing of 60 cm between rows and 20 cm between plants within a row with a gross plot area of (6 m x 5 m= 30 m 2 ).

Grain yield
Six central rows (5.0 m x 3.6 m = 18 m 2 ) were harvested for the determination of grain yield. Grain yield was adjusted to 12.5% moisture content. Ten plants were randomly selected from the six central rows to determine yield and yield components, which consisted of plant height, number of pods per plant, and number of seeds per pod.

Data analysis
All the agronomic data were recorded and being subjected to analysis using the R statistical Software Version 3.4.1. Effects were considered significant in all statistical calculations if the Pvalues were < 0.05. Means were separated using Fisher's least significant difference (LSD) test.

Results and Discussion
According to the combined analysis of variance results, there were significant differences observed among the cowpea varieties for plant height, pods per plant, 100 seed weight and grain yield but no significant difference was observed among the varieties for the number of seeds per pod (Table 1). This finding is in agreement with the previous works of Tekle (2014); Gereziher et al. (2018) who reported that there were significant variations observed among the cowpea varieties for yield and yield-related traits.
Pant height ranged from 69 (cm) for the variety Bole at Dasenech to 159 (cm) for the variety TVU at Gynagatom (Table 3). The results revealed that the mean values for plant height ranged from 84.89 (cm) for the variety Bole to 120.67 (cm) for TVU across locations ( Table 2). The maximum number of pods per plant (69) was recorded for the variety TVU at Gnangatom, while the minimum (21) was noted for the variety Bole at Hammer (Table 3). The combined analysis of variance results depicted that the mean values for the number of pods per plant ranged from (24.33) for the variety Bole to (46.90) for the variety TVU (Table 2). Though no significant differences were observed among the varieties for the number of seeds per pod, the maximum number of seeds per pod (20) was obtained for the variety Kankeit at Dasenech, while the minimum (14) was recorded from the variety Bole at Gnangatom (Table 3). The combined analysis of variance result depicted that the mean values for the number of seeds per pod ranged from (16.67) for the variety Bole to (17.89) for the varieties Kankeit and TVU (Table 3). The values for 100 seed weight in gram (g) ranged from (9) for the variety TVU at Gnangatom to (26) for the variety Kankeit at Dasenech. The results also showed that the overall mean values for the hundred seed weight ranged from 17.11 (g) for the variety TVU to 21.11 (g) for the variety black eye bean (Table 3).
The combined analysis of variance results revealed that there were significant differences observed among the cowpea varieties for grain yield (Table 1). The combined analysis of variance results showed that the overall mean values for grain yield ranged from 1695.3 kg ha -1 for the variety black eye bean to 2457.0 kg ha -1 for the variety Kankeit (Table 2). The values for grain yield ranged from 1485 kg ha -1 for the variety black eye bean at Hammer to 2587 kg ha -1 for the variety Kankeit at Dasenech (Table 3).   The highest overall mean grain yield of 2457.0 kg ha -1 and 2042.0 kg ha -1 were recorded for the varieties Cankeit and TVU, respectively while the minimum 1695.3 kg ha -1 was noted for the cowpea variety black eye bean. Therefore, the cowpea variety Kankeit and TVU could be recommended for the study areas however further research should be done to put the recommendation on a strong basis.