Selection of drought tolerant wheat genotypes for Arid and Semi-arid lands (ASALS) of Kenya, which consist of 83% of total land area, can provide alternative agricultural land for expansion. To reduce cost of dryland research, simulated drought under a rain shelter offers a good alternative for screening because marginal areas are vast and widespread. Four moisture regimes which simulated terminal, early, mid-and late-season droughts were created under the mobile rain shelter at Njoro in 1998/99, by applying drip irrigation (i) up to seedling stage (70 mm) (ii) through tillering (82 mm) (iii) up to anthesis (94 mm) and (iv) grain filling (106 mm), respectively, to determine drought responses of five wheat varieties (Duma, R748, R830, R831 and R833) and identify drought tolerant genotypes. Control watering regime had 118 mm applied at all stages. Yield and yield components in each season and the two seasons combined showed significant difference (P<0.05 and 0.01, respectively). Early drought during seedling stage and tillering caused significant reduction in plant heights, tiller number and number of reproductive tillers. However, drought from anthesis and grain filling to maturity caused significant (P<0.05) reduction in ear length (16.9%), spikelets/head (14.3%), 1000-kernel weights (22.4%) and an increase in the number of sterile florets/head (28.3%), compared to control. Seedling and reproductive stage (anthesis and grain filling) droughts caused the highest grain yield reduction (25 and 67%, respectively), indicating that they were the most critical stages in moisture requirement compared to control. Genotype R748 out-performed Duma (check) in all moisture regimes, and was recommended for field testing and participatory evaluation. From this study, it is possible to select drought tolerant cultivars using mobile rain shelters by drought simulations in Kenya.Key Words: Duma, irrigation, dryland, moisture stress RÉSUMÉLa sélection des génotypes tolérant a la sécheresse pour les terres arides et semi-arides (ASALS) du Kenya, lesquelles consistent a 83% de la surface de terre, peut pourvenir de terre pour l'expansion agricole. Pour réduire le coût de la recherche dans les régions arides, la sécheresse simulée a l'abris de la pluie offre une bonne alternative pour la sélection parce que les aires marginales sont vastes et éparpillées. Pour les régimes humides qui sont simulés a l'état terminal, matinal, en pleine et en retard des saisons séches étaient crées sous un abri mobile a Njoro entre 1998/1999, par application de l'irrigation par goutte 1) jusqu'a l' étape de semis (70 mm) ii) a travers le labourage (82 mm), iii) jusqu'a l'étape d'anthere (94 mm) et iv) graine nourrissante (106 mm), respectivement pour déterminer les réponses a la sécheresse aux cinq variétés de blé (Duma, R748, R830, R831 et R833) et identifier les génotypes tolérant la sécheresse. Le contrôle du régime en eau avait 118 mm appliqués a toutes les étapes. Les composants de la production et du rendement dans chaque saison et les deu...

Thirty six pearl millet genotypes were evaluated in randomized complete block design with two replications during 2011/2012 at two locations to study the magnitude of genotype by environment interaction for yield and yield related traits and identify the most stable high yielding genotypes. ANOVA of data at individual locations revealed significant differences among genotypes at Marigat and Koibatek for all yield components. Combined mean analysis of variance showed that the Lagat et al.; JEAI, 21(1): 1-18, 2018; Article no.JEAI.24311 2 Genotype and location main effects and the genotype by environment interaction were highly significant (P≤0.01) for grain yield and other traits, indicating differential response of genotypes across testing locations and the need for stability analysis. Marigat was the most suitable environment and gave highest mean grain yield of 3620 kg/ha. The lowest yield 870 Kg/ha was recorded at Koibatek. Genotypes EUP 32, EUP 35, EUP 19 and EUP 10 produced high mean yield of 3530, 3080, 2690 and 2590 kg/ha respectively. The lowest grain 1290 kg/ha was obtained from genotype EUP 4.Based on the parameters of stability, three stable (widely adapted) and high yielding genotypes (EUP 34, EUP 18, and EUP 9) were identified. They also out-yield the standard open pollinated variety (OPV) check, Kat PM2. Genotypes EUP 32 was the highest yielding across all sites followed by EUP 35 and could be recommended for further multi-location evaluation in warmer environment and possible release for commercial production. The findings of this study showed that pearl millet hybrids have high potential for commercial production in Kenya than the OPVs. The ANOVA results showed that the effects of environments, genotypes and genotype x environment interaction (GE) were important in trait expression and performance of genotypes. In addition, it was observed that amount of rainfall received at both vegetative and post-anthesis phases and temperature had an effect on grain yield. The GGE biplot analysis characterised the environments in terms of stability and productivity, where Marigat was the best for grain yield; implying that environment-specific selection should be adopted. Genotypes EUP 34, EUP 18, and EUP 9 were the best performing since they out yielded the standard OPV check. These stable high yielding genotypes can be evaluated further in varied agro-ecologies and recommended for release as commercial hybrid varieties in ASALs of Kenya. Original Research Article

No abstract

Pigeonpea contributes to food and nutrition security among poor households in urban and rural areas. Globally it is characterized by stagnant and unstable yield due to its susceptibility to various stresses including the pod borer (Helicoverpa armigera) which causes substantial damage to the crop and may result in absolute economic yield loss. The existing cultivated pigeonpea are susceptible to pod borer with only a few genotypes reported to be tolerant based on pod and seed damage. Limited information is available on morphological and biochemical traits associated with pod borer resistance among the existing genotypes. This study was therefore carried out to identify diversified sources of resistance against pod borer damage. The study was set up to assess traits that may contribute to pod borer resistance among 12 selected elite pigeonpea genotypes in three replicates and means were separated based on LSD test using Genstat software. The field study was carried out in Kerio Valley during the long rains of April-September of 2017. The genotypes varied significantly for all the parameters measured at P≤0.05 with a mean of 608.33 g/100 g (crude protein), 175.61 mg/100 g (total phenol), 19.85 mg/100 g (total flavonoid), 0.448 mm (trichome length), 210.6 / 4 mm2(trichome density) and 0.353 mm(depth of locules). Significant negative correlation was also observed between total phenol, total flavonoid, depth of locules, trichome length and trichome density with pod damage. However, a positive correlation was recorded between crude proteins with pod damage.  These results reveal that, host plant resistance is an association of several morphological and biochemical traits. Therefore, these genotypes with elevated levels can be selected and utilized in breeding towards improving resistance to pod borer in pigeonpea.

No abstract