Joseph P. Gweyi-Onyango

Genotypic Responses of Cowpea ( Vigna unguiculata) to Sub-Optimal Phosphorus Supply in Alfsols of Western Kenya: A Comparative Analysis of Legumes

Abstract Western parts of Kenya are characterized by acid soils with phosphorus [P] deficiency and aluminum [Al] phytotoxicity. Reports indicate a declining trend in yields of legumes such as cowpeas. Though legumes can fix N, starter phosphorus need to be supplied for better yields and more often plants develop adaptive strategies for better P acquisition; probably through increased Al tolerance by carboxylates exudation, improved nodulation as a result of high P and better root development. Present study examined mutual relationship between P and nodulation in explaining yield differences between Cowpea (Vigna unguiculata) varieties: Elanda (ELn, high yielding) and Inzeku (INz; moderate yielding), Ground nut (Arachis hypogea)-GN and Bambara nuts (Vigna subterrenea(Verdc) - BBN with proven P efficiency and Bean (Phaseolus vulgarisL) varieties Rosecoco (RCC) and Edwin (ED); low P efficient formed basis for comparison. The experiment was conducted at Masinde Muliro University field station from April 2009 and experimental design was CRBD having split plot with P as main plots (+P; or –P), whereas GN, BBN, ELn, INz, RCC and ED legumes were randomized within the P treatments. Legume genotypes were replicated four times. There were no differences in shoot biomass with +P and –P (INz), but ELn showed higher shoot DM with +P as compared with –P (significant p<0.05). Similar trends were replicated with nodulation with P supply. Shoot DM and nodulation were positively correlated for ELn (r2=0.99; +P and r2=0.68; -P) but not INz. Correlations were negative for beans and performance of BBN with +P and –P showed trends similar with Inz genotype. Sub-optimal P supply with concomitant enhancing nodulation in INz could not explain genotypic differences in yields, since high yielding BBN lacked this trait with additional P. Factors like high proton concentration and Al saturation need to be assessed and likely an interaction between P and Al through enhanced exudation of carboxylates may give more insights to cowpea genotypic differences.

Grain yield responses of lowland rice varieties to increased amount of nitrogen fertilizer under tropical highland conditions in central Kenya

Abstract Tropical highland conditions in Mwea Kenya, ensure the high radiation and the large day–night temperature differences. Such conditions are generally believed to promote rice growth and yield, but the current grain yield is lower than the expectation. In the current standard N fertilizer practice in Mwea, 75 kg nitrogen (N) ha−1 is applied in three splits at fixed timing. The effects of increases in N fertilizer amount (125, 175, and 225 kg N ha−1) on rice growth and yield were evaluated to test the hypothesis that unachieved high rice grain yield in Mwea is due to insufficient amount of N fertilizer. Two popular lowland varieties in Mwea (Basmati 370 and BW196) and two varieties reported as high yielding in other countries (Takanari and IR72) were used. Shoot dry weight (DW) increased with increases in the amount of N fertilizer applied in three splits at fixed timing, irrespective of variety. It reached approximately 20 t ha−1 under increased N conditions (>75 kg N ha−1) in several cases, indicating that high biomass production could be achieved by increasing N application rate. However, the increased biomass did not increase grain yield, due to decreased grain filling under high N conditions in all varieties. Thus, N amounts above 75 kg ha−1 were ineffective for increasing grain yields in Mwea, where N fertilizer was applied in three splits at fixed timing. Increasing influence of low temperature under high N conditions may be one of the reasons for the decreased grain filling in Mwea.

Plant Row Spacing Effect on Growth and Yield of Green Pepper (Capsicum annuum L.) in Western Kenya

Green pepper production based on the package of recommendations developed has not given the desired growth and yield performances in the world and specifically Kenya. Information is required with which to evolve the agronomic practices that will be adopted to maximize yield in green pepper production. Great attention should be paid when selecting the most appropriate spacing where there are very few reports and limited information regarding plant spacing in cultivation of the crop under the agro-climatic conditions of Kenya. Therefore, a field study was carried out at the Alupe Research Station, Busia County, to evaluate the growth and yield responses of green pepper under three row plant spacings namely: 50x40 cm, 40x40 cm and 30x40 cm during the long and short rainy seasons of 2015. The experiment was set up in a randomized complete block design with three replicates. The treatment effects were measured on plant growth for 12 weeks and ripe fruit yield parameters which were later cleaned statistically analyzed. The plant spacing had significant variation in almost all the growth and yield components except the fruit length. In Original Research Article Edgar et al.; ACRI, 7(3): 1-9, 2017; Article no.ACRI.33101 2 both seasons, the number of branches per plant, stem girth and number of fruits per plant were found to be significantly increased with the increasing of plant spacing but the plant height, number of leaves per plant, fruit breadth and yield per plant were found to be significantly increased with the decreasing plant spacing. The highest yield per plant of 555.1 g and 551.8 g were realized during the short and long rainy seasons respectively in the 40 by 40 cm spacing treatment. Considering the yield of fruits per plant, the 40 by 40 cm plant spacing appeared to be the most recommendable for the cultivation of green pepper.

Agromorphological Performance and Character Association of Finger Millet under Varying Phosphorus Regimes

Finger millet production on more than 30% of world arable land is limited by P availability and more than 70% in the semi-arid and marginalized areas which covers most of the Sub-Saharan Africa. Phosphorus is one of the most important elements significantly affecting plant growth and metabolism. Three finger millet varieties (U-15, P-224 and Ikhulule) were evaluated under four P fertilizer levels (0, 12.5, 25 and 37.5 kg ha -1 P 2 O 5 ) at the International Crops Research Institute for the Semi-Arid Tropics Station, Alupe and the Kenya Agricultural and Livestock Research Organization Station, Kakamega during the long and short rainy seasons of 2015 with the aim of determining their agromorphological response and trait associations. The on-station experiments were laid out in Randomized Complete Block Design in factorial arrangement with three replications. The statistical analysis of phosphorus levels and variety exhibited significant differences (P<0.05) to stand vigor, plant height, leaf blade length, number of leaves and lodging. The results revealed that application of 25 kg ha -1 P 2 O 5 rate led to the tallest plants (65.0 cm), longest leaf blades (58.0 cm) and highest number of leaves per plant (16) at Alupe site while 37.5 kg ha -1 P 2 O 5 rate eliciting the tallest plants (58.79 cm), longest leaf blades (51.44 cm) and highest number of leaves per plant (13) at Kakamega site. The highest rate led to the greatest vigor in both sites for both seasons while the control had the poorest vigor. Variety P-224 showed the highest lodging count with 32 out of 246 plants per experimental unit during the rainy season at Kakamega. The unit increase in grain yield was positively and significantly correlated with increased values of the harvest index (r=0.375), number of leaves (r=0.393) and plant height (r=0.431) but negatively and significantly correlated to the 1000-grain mass (r=-0.578) and lodging (r=-0.233). The best phosphorus treatment for most of the parameters was 25 kg ha -1 P 2 O 5 at Alupe while maximum levels of the study parameters were realized under the 37.5 kg ha -1 P 2 O 5 rate at Kakamega.

Finger Millet (Eleusine coracana) Fodder Yield Potential and Nutritive Value under Different Levels of Phosphorus in Rainfed Conditions

Scarcity of fodder is the major limiting factor for increasing livestock production in Kenya. With rising energy costs and declining water levels in the semi-arid tropics and sub-tropics, crops that use less water like finger millet could become an alternate fodder crop. The fodder potential of three finger millet varieties (U-15, P-224 and a local check) were evaluated under four P fertilizer levels (0, 12.5, 25 and 37.5 kg ha-1 P2O5) at three sites in Kenya for two cropping seasons. The trials were laid in randomized complete block design in factorial arrangement and replicated three times. A maximum of 28,189 kg ha-1 fresh stover yield was realized in the 25 kg ha-1 P2O5 treatment and consequently 11,616 kg ha-1 dry stover yield. The 25 kg ha-1 rate elicited the highest fresh stover yield at Kakamega and Alupe for both seasons while at Kiboko a linear increase was observed on the stover yield with increasing rates where the highest rate had more than 15% yield compared to the control. The varieties also showed significant differences in all the sites with the local variety, Ikhulule, showing the highest fresh and dry stover yield at Kakamega and Alupe peaking at 28,852 and 12,826 kg ha-1 fresh and dry stover yields respectively. Interactions between variety and phosphorus rates were revealed on the crude protein content of the finger millet stover. At Kiboko, the highest crude protein (11.0%) on varieties P-224 and U-15 was exhibited at the highest rate while on the local variety, Ekalakala, the highest protein (10.9%) was realized at the 25 kg ha-1 P2O5. At Kakamega and Alupe, the highest protein was observed on the local variety, Ikhulule at 12.5 kg ha-1 P2O5 rate with variety P-224 and U-15 showing the highest at the 25 and 37.5 kg ha-1 P2O5 respectively. Therefore, finger millet can provide a unique opportunity to improve the availability of fodder to smallholder livestock farmers.

Water Stress Effect on Total Antioxiant Activity and Total Phenolic Content of Solanum scabrum Mill and Solanum scabrum in Kiambu, Kenya

Aims: The aims of this study were to investigate water stress effect on total phenolics and total antioxidants of selected African nightshades and determine any possible variations in the amount of total phenolics and total antioxidants among the accessions grown. Study Design: Study was conducted on the basis of randomized complete block design. Place and Duration of Study: The study was carried out in Kenyatta University Agricultural farm in Kiambu County of Kenya. Greenhouse experiments were carried out in the same farm. Methodology: A greenhouse and field experiment was conducted to investigate effects of water stress on total phenolic and total antioxidant contents of Solanum scabrum and Solanum villosum. The two African nightshades were subjected to different soil water tensions of 15cbars, 50cbars and 85cbars. After a month of transplanting, samples from the different blocks were collected fortnightly and prepared for total phenolic and total antioxidant determination. Short Research Article Okello et al.; IJBCRR, 17(1): 1-9, 2017; Article no.IJBCRR.33715 2 Results: Obtained data showed that Solanum villosum had a higher concentration of both the total phenolics and antioxidant activity in the shoots (46.41 g/Kg total phenolic content and 52.68% total antioxidant activity) while Solanum scabrum had higher concentration in the roots (25.06 g/Kg total phenolic content and 27.18% total antioxidant activity). Conclusion: Total phenolics and total antioxidant accumulation not only depend on irrigation variation but also on the accessions grown.

Commodity Systems Assessment Methodology of Postharvest Losses in Vegetable Amaranths: The Case of Tamale, Ghana

A semistructured questionnaire based on the commodity system assessment methodology (CSAM) was used to determine postharvest losses in vegetable amaranths (VA). Fifty producers and retailers were randomly selected from five and four major VA producing areas and markets, respectively, and interviewed. Data obtained were subjected to descriptive statistical analyses. The survey revealed that absence of laws, regulation, incentives, and inadequate technical information affected the production of VA. The utmost preproduction challenge was poor quality seeds with poor seed yield (35%), low viability (19%), and nontrueness (46%). It was noted that some cultural practices including planting pattern and density, irrigation, and fertiliser use had effects on postharvest losses. Some postharvest practices used were cleaning with water, trimming, sorting, and grading. Usually the produce was transported to marketing centers by cars and motor cycle trailers. Generally poor temperature management after harvest was a big challenge for the postharvest handling of VA. The potential of vegetable amaranths as a commodity in the study area can be enhanced by providing the necessary institutional support, incentives, and use of good management practices along the value chain. An interdisciplinary approach and quantification of losses along the chain are recommended for any future study.

Characterization and Documentation of Factors Contributing to Production and Consumption of African Leafy Vegetables (ALVs) in Kiambu and Kirinyaga Counties in Kenya

The aim of the study was to evaluate popular ALVs in two counties; i.e. Kiambu and Kirinyaga counties in Kenya. Focus group discussion (FGD) and a field survey were employed. The study was carried out in the two counties in Central Kenya between January and February; 2015. Purposive sampling method was used where 67 respondents (37 and 30) Kiambu and Kirinyaga counties respectively; were interviewed. One FGD was carried out in each county. The findings indicated that; about seven ALVs were cultivated and consumed in the two counties. Vegetable amaranth and nightshade were the most dominant indigenous vegetables in both counties (83.8% and 81.1%) in Kiambu and (93.3% and 83.3%) in Kirinyaga respectively. These were followed by, spider plants, pumpkin leaves, cow peas leaves and jute mallow at 54.1%, 35.1% 32.4% and 21.6% Original Research Article Rozy et al.; ARJA, 1(3): 1-9, 2016; Article no.ARJA.28734 2 respectively in Kiambu and 30%, 56.7%, 30% and 6.7% in Kirinyaga respectively. Furthermore, large number of farmers (59% and 66.7%) in Kiambu and Kirinyaga respectively grew ALVs for nutrition or health benefit in both counties. The finding also revealed that over 50% of the respondents in both counties cultivated ALVs both for domestic and commercial purposes. Conclusion: Two ALVs species (Amaranthus and Solanum spp) were most popular in the studied region. However a large diversity of cultivated and consumed ALVs seems to exist in Central Kenya. Production and utilization of the vegetables for nutrition and health benefit was major incentive to continual cultivation of ALVs.

Phosphorus Influence on Plant Tissue Nitrogen Contents and Yield Attributes of Finger Millet Varieties in Semi-arid Region of Kenya

The experiment was conducted with the aim of evaluating the effect of differential levels of P on finger millet accumulation of N and yield components. On-station experiments were conducted at the KALRO-Kiboko crops research station in Makueni County during the short and long rains of 2014 and 2015 respectively. There were 4 levels of P (0, 12.5, 25 and 37.5 kg ha-1 P2O5) and three varieties (U-15, P-224 and Ekalakala). Ekalakala was the local check while 0 kg/ha P2O5 was the control. The trial was laid out in a randomized complete block design and fitted in factorial arrangement with three replicates given a total of 36 plots. Soil sampling was at a depth of 0-30 cm on all the plots and analytical results showed moderately available P but very low N, organic carbon and zinc. Significant differences (P=.05) were observed between the phosphate levels on the nitrogen contents in plant parts with the control showing the lowest N accumulation of 4.95% and 4.90% for the short and long rains respectively while the 25 kg ha-1 P2O5 rate had the highest with 5.66% in the short rains and 5.14% in the long rains. The stem contained the highest nitrogen content while the roots had the lowest. Phosphate rates did not have significant influence on the yield components except the finger width while the varieties varied significantly (P=.05) on the productive tillers, panicle number, grains per spikelet and the harvest index. Variety U-15 had the highest yield for both seasons with a maximum of 3410 kg ha-1 for the short rains. The newly released variety (U-15) responded well to moderate P supplemented at 25 kg ha-1 P2O5 thus can efficiently utilize N in soils with low N like in Makueni and is highly recommended. The optimal P for the yield and N accumulation was 25 kg ha-1 P2O5 and beyond this point the P would not be translated to profitable yield but a loss to the farmer in the short run.

Secondary School Teachers' Understanding of Energy Flow in Ecosystems: Carbon Sink and Sequestration Perspective

Abstract The energy and other environmental conservation measures are emerging issues of concern all across the world. The awareness on climate change and sustainable environmental resource utilization are being discussed globally in all sectors of development. It is for this reason; the study investigated Kenyan biology teachers’ understanding of soil carbon sink and sequestration in Kenyan ecosystems as emerging issues. The study aimed at relating biology teaching content to a wider scope of energy flow in ecosystem; a subject taught and assessed by teachers of different secondary schools in Kenya. The study employed descriptive research design. Twenty- four (24) secondary school teachers were randomly selected and sampled from thirty- six (36) secondary schools of Lugari District in Kenya. Self-valuation questionnaire (SVQ) was used to capture key information on understanding of soil carbon sequestration as some of the emerging issues in terrestrial ecosystems. The results revealed a rich understanding of green house effects on the general environment among teachers assessed. A high percentage of the teachers demonstrated understanding climate changes phenomena in their response (21%). However, a high percentage (71%) of selected and assessed teachers lacked clear grasp on carbon sequestration concepts and phenomena beyond photosynthesis process. Further, the teachers’ demonstrated poor understanding of premiums paid by industrialized nations in a bid to mitigate environmental pollution, particularly via Green House Gases (GHGs) (70%). The study, in conclusion revealed that, there was a general ecosystems knowledge gap among biology teachers in Kenyan secondary schools concerning emerging issues particularly in ecology and is, therefore, important that they get updates by undergoing refresher courses as a means of strengthening their competencies. It is also probable that the teachers may have acquired the misconceptions during the period of study or it was an indirect manifestation of complexes of interrelations between biological processes.