ON-FARM EVALUATION OF NEW GREEN GRAM VARIETIES IN THE ARID AND SEMI-ARID AREAS OF EASTERN KENYA

Abstract

Green gram (Vigna radiata (L) Wilczek) is an important staple crop and a source of livelihood to most small scale farmers in the semi-arid of eastern Kenya. The current production of green grams cannot meet its demand in the local and export markets. The available green gram varieties are low yielding, have a small grain size and are late maturing. Farmer’s participatory field experiments were conducted in Meru and Tharaka-Nithi Counties to evaluate the adaptability and acceptability of three new green gram varieties. The trials were laid in a Randomized Complete Block Design with four plots replicated thrice. The objectives were to evaluate the green gram varieties for yield under farmer’s management, assess the farmers’ preferences and test their adaptability in the region. The treatments comprised of green gram varieties; Karembo, Ndengu tosha, Ndengu Biashara and N26 (control). The varieties were planted in plots of 5m x 5m at a spacing of 60 cm x 20 cm and DAP was used as a source of nutrients. The parameters evaluated were grain yield, number of pods per plant and number of seeds per pod. The findings indicated that in Tharaka-Nithi County, Karembo variety was highest in yields with 1.171 t ha^-1 , an increase of 74.5% above the control (0.671 t ha^-1). Biashara variety followed with 1.02 t ha^-1 ,an increase of 34.4% above the control (0.671 t ha^-1). In Meru County, Biashara variety gave the highest yields of 1.99t ha^-1, an increase of 362.8% above the control (0.43tha^1-). Karembo variety followed with 1.47t ha^-1, an increase of 241.9% above the local check (0.43tha^-1). The local check (N26) had a grain yield of 0.43tha^-1. There was a significant difference (p˂0.05) among the four green gram varieties on grain yield in Meru County. There was a similar trend for both the number of seeds per pod and number of pods per plant where Ndengu Tosha produced the most seeds per pod and pods per plant in both Tharaka-Nithi and Meru counties with a mean of 15.4 and 18.4 seeds per pod and 25 and 27.6 pods per plant respectively. This was followed by Biashara that produced a mean of 11 seeds per pod and 22.2 pods per plant in Tharaka-nithi and 13.4 seeds per pod 26.6 pods per plant in Meru County. The local variety N26 produced the least number of pods per plant in both sites having a mean of 5.6 seeds per pod and 10.4 pods per plant in Tharaka-nithi and 4.4 seeds per pod, 16.4 pods per plant in Meru County. During the evaluation, the farmers set their criteria for evaluating the performance of the varieties. They used different criteria to evaluate and assess the green gram varieties. The major attributes used in the evaluation included pest and disease tolerance, high grain yield and non-shattering ability. The attributes were ranked through pairwise ranking and the first four were used to rank the varieties in order of preference. Ndengu Biashara ranked highest because of its early maturity and high yields, followed by Karembo and Tosha. The results revealed that adoption of these varieties would increase yields and in turn increase income for the farmers. It would also increase the diversity of varieties in the region.  Seed bulking would be an important intervention in dissemination of the new seeds.