Browsing by Author "Otieno, S."
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Item Desiree: A Potato Variety for Quality Chips(KALRO, 2017) Onditi, O.J.; Karinga, J.K. ; Nderitu, S.W.K.; Nyongesa, M.; Mbiyu, W.M.; Oyoo, J.; Otieno, S.; Muthoni, J.M.; Kabira, J.N.Desiree is a short potato variety (about 0.7 metres in high) with strong erect stems, dark green medium sized leaves and rare light pink flowers.Item Effect of Plant Density and Row Width on Canopy Architecture in Sorghum(2013) Stutzel, H.; Otieno, S.; Uptmoor, R.; Duensing, R.; Kenya Agricultural research Institute- National Potato Research CentrePlant architecture can be used to simulate resource acquisition, biomass production and plant stand levels thus increasing resource capture efficiencies to be compared between architectures. In the present study, five biofuel sorghum genotypes and one maize hybrid were grown at two planting densities (20 plants/m2 and 30 plants/m2) and two row width (40 cm and 67 cm). The elevation angle, phyllotaxy and blade curvature orientation were monitored using 3 D Polhemus digitizer and the shoot organ characteristics (leaf area, leaf length, leaf area index, total biomass) were monitored by destructive measurements. Leaf area indices calculated from destructive measurements were compared with those of nondestructive measurements using the LAI2000 device (Licor, Lincoln, USA). Variation of plant density caused significant changes in architectural traits like leaf area index (LAI) and total biomass.Item Effect of Plant Density and Row Width on Canopy Architecture in Sorghum(2013) Otieno, S.; Stütze, H.; Uptmoor, R.; Duensing, R.; Kenya Agricultural Research Institute - National Potato Research CentrePlant architecture can be used to simulate resource acquisition, biomass production and plant stand levels thus increasing resource capture efficiencies to be compared between architectures. In the present study, five biofuel sorghum genotypes and one maize hybrid were grown at two planting densities (20 plants/m² and 30 plants/m³) and two row width (40 cm and 67 cm). The elevation angle, phyllotaxy and blade curvature orientation were monitored using 3 D Polhemus digitizer and the shoot organ characteristics (leaf area, leaf length, leaf area index, total biomass) were monitored by destructive measurements. Leaf area indices calculated from destructive measurements were compared with those of nondestructive measurements using the LA12000 device (Licor, Lincoln, USA). Variation of plant density caused significant changes in architectural traits like leaf area index (LAI) and total hiomass. From early stages of crop growth, leaf elevation angle and leaf to leaf angle were markedly affected by treatments, with the measured leaf length showing a strong correlation (r=0.85) with the digitized leaf length. An interaction between plant width and population density on total biomass of the crops was determined for one genotype (S. bicolor S. sudanense) displaying the highest biomass and leaf area index (LAI) under all conditions. Significant difference was detected on the leaf fresh weight, leaf dry weight, and mean leaf tip angle across the canopy strata of the different plant densities and row widths for mean comparison at Tukey test P≤0.05. Significant interaction of row width and density was observed when plant densities of 20 plants/m² and 30 plants /m³ were used. Increasing row width from 40 cm to 67 cm led to an increase in total dry weight. One genotype gave a desirable architectural trait which can be used as an excellent target for genetic selection to enhance yields.Item Effect of Yadbiovitalizer on yield of Irish Potatoes in Limuru area, Kenya(2013) Otipa, M.; Muiru, E.; Lung'aho, C.; Oyoo, J.; Otieno, S.Organic resources play dominant role in soil fertility management in the tropics through their short-term effects on nutrient supply and longer-term contribution to soil organic matter (SOM) formation. Biovitalizer herein referred to as 'YAD' is a locally manufactured organic product and is reported to be a slow release fertilizer. A field experiment was set up to investigate the effects of different applications of manure and fertilizers on the growth and fresh tuber weight of potatoes (Solanum tuberosum) in Limuru area, Kiambu County in Kenya. The treatments consisted of Diammonium phosphate (DAP)fertilizer(l8:46:0) at 500kg/ha, Farmyard manure (FYM) (I tonlha), YAD Bio Vitalizer® (750 kg/ha), Control (no fertilizer or manure applied), DAP (250 kg/ hal + FYM (500 kglha), DAP (250 kg/ha) + YAD (375 kg/ha, FYM (500 kglha) + YAD (375 kglha).Treatments of YAD alone were applied with Ecoh balance fohar feed 2 weeks after emergence and then after every other week. The test variety was Tigoni. The experiment was conducted during the short rains season in 2010 and the long rains season in 2011 and was laid out in randomized complete block design (RCBD) with three replications.Plant spacing was 75 cm between rows and 30 cm between plants .Results showed that there were significant differences in number of tubers during the short rain season of 2010 but not during the long rain season of 2011 at P:S0.05. DAP+ FYM treatment had the highest number of tubers and also the highest tuber weights in both seasons. YAD yielded the highest ware yield (5.7 tons/ha) and the lowest chatt yield( 0.2 tons/ha) during the short rains season of 2010. The experiments need to be repeated on smallholder farmers' fields where the masking effects of the residual fertilizers could be eliminated. In addition, the cost benefit ratio of different fertilizer combinations especially the use of organic fertilizers needs to be evaluated at farmers' fields so as to make the most profitable recommendations to Irish potato producers in Kenya.Item Effect of Yadbiovitalizer on Yield of Irish Potatoes In Limuru Area, Kenya(2013) Oyoo, J.; Muiru, E.; Otieno, S.; Otipa, M.; Lung'aho.; Kenya Agricultural Research Institute, National Potatoe Research Centre Tigoni P. O Box 338-00217 LimuruOrganic resources playa dominant role in soil fertility management in the tropics through their short-term effects on nutrient supply and longer-term contribution to soil organic matter (SOM) formation. YadBiovitalizer herein reffered to as 'YAD' is a locally manufactured organic product and is reported to be a slow release fertilizer. A field experiment was set up to investigate the effects of different applications of manure and fertilizers on the growth and fresh tuber weight of potatoes (Solanum tuberosum) in Limuru area, Kiambu County in Kenya. The treatments consisted of Ammonium phosphate (DAP)fertilizer(l8:46:0) at 500kg/ha, Farmyard manure (FYM) (I toniha), YAD Bio Vitalizer® (750 kg/ha), Control (no fertilizer or manure applied), DAP (250 kg! ha) + FYM (500 kg/ha), DAP (250 kg/ha) + YAD (375 kg/ha, FYM (500 kg/ha) + YAD (375 kg/ha).Treatments of YAD alone were applied with Eco balance foliar feed 2 weeks after emergence and then after every other week. The test variety was Tigoni. The experiment was conducted during the short rains season in 2010 and the long rains season in 2011 and was laid out in randomized complete block design (RCBD) with three replications. Plant spacing was 75 cm between rows and 30 cm between plants .Results showed that there were significant differences in number of tubers during the short rain season of 2010 but not during the long rain season of 2011 at P: s0.05. DAP+ FYM treatment had the highest number of tubers and also the highest tuber weights in both seasons. YAD yielded the highest ware yield (5.7 tons/ha) and the lowest chatt yield (0.2 tons/ha) during the short rains season of 2010. The experiments need to be repeated on smallholder farmers' fields where the masking effects of the residual fertilizers could be eliminated. In addition, the cost benefit ratio of different fertilizer combinations especially the use of organic fertilizers needs to be evaluated at farmers' fields so as to make the most profitable recommendations to Irish potato producers in Kenya.Item Identifying and Controlling Major Passion Fruit Diseases for Increased Yields of Quality Passion Fruits(Kenya Agricultural and Livestock Research Organization, 2017) Pole, F.N.; Oyoo, J.; Katama, C.; Otipa, M.; Otieno, S.; Sowa, M.; Kenya Agricultural and Livestock Research OrganizationPassion fruit is a key fruit produced commercially in Kenya and ranks third among the export fruits. The production of passion fruits and its growth as a profitable enterprise however, depends on the maximum utilization of the factors of production while reducing costs. One of the major challenges encountered by passion fruit farmers is the incidences of diseases. These can reduce yields of fruits by upto 90% or lead to total crop failure. Identification of the disease and controlling them at their initials stages is a sure way of increasing yields of quality fruits that will compete effectively in the market with fruits from other areas.Item Kenya Baraka: A Potato Variety with Good Chipping and Mashing Qualities(Kenya Agricultural and Livestock Research Orgnaization, 2017) Onditi, O.J.; Karinga, J.K.; Nderitu, S.W.K.; Nyongesa, M.; Mbiyu, W.M.; Oyoo, J.; Otieno, S.; Muthoni, J.N.; Kabira, J.N.; Kenya Agricultural and Livestock Research OrgnaizationKenya Baraka is a medium sized potato plant with strong erect-stems, green medium-sized leaves and rare white flowers. The variety produces a vigorous crop with good ground cover.Item Kenya Mavuno: A High Yielding Late Blight Tolerant Potato Variety With Good Cooking and Processing Qualities(Kenya Agricultural & Livestock Research Organization (KALRO), 2017) Onditi, O.J.; Karinga, J.K.; Nderitu, S.W.K.; Nyongesa, M.; Mbiyu,W.M.; Oyoo, J.; Otieno, S.; Muthoni, J.M.; Kabira, J.N.; Kenya Agricultural & Livestock Research Organization (KALRO)Kenya Mavuno is a tall potato plant attaining a plant height of about 1 metre. It has strong semi erect stems, green medium sized leaves and abundant white flowers with regular flowering habit. The variety produces a vigorous crop with good ground cover.Ranges from 20-30 t/ha (72-110 bags of 110 kg per acre) under sufficient rainfall and recommended crop production ractices.Item Kenya Sifa: A High Yielding Late Blight Tolerant Potato Variety with Good Cooking and Processing Qualities(Kenya Agricultural and Livestock Research Organization, 2017) Onditi, O.J.; Karinga, J.K.; Nderitu, S.W.K.; Nyongesa, M.; Mbiyu, W.M.; Oyoo, J.; Otieno, S.; Muthoni, J.M.; Kabira, J.N.; Kenya Agricultural and Livestock Research OrganizationThis is a very tall potato variety (slightly above 1metre). It has strong erect stems, dark green broad leaves and slightly abundant light purple flowers with regular flowering habit. The variety produces a vigorous crop with good ground cover. Ranges between 20-30 t/ha (72-110 bags of 110 kg per acre) under sufficient rainfall and recommended crop production practices.Item Micropropagation of Different Potato Cultivars in Upscaling Seed Potato Programme in Kenya(2013) Otieno, S.; Muthoni, J.; Lung'aho, C.; Oyoo, J.; ; Nyongesa, M.; Kabira, J.; Kenya Agricultural Research Institute; Kenya Agricultural Research Institute – National Potato Research CentreScarcity of good quality seed is a major constraint in potato (Solanum tuberosum) production coupled by high expensive gelling agent used in the micro propagation to produce clean pre-basic seed in the country. A study was set out to compare the performance of liquid and solid media in potato micro propagation using 10 potato cultivars. Sections of potato plantlet containing one node were aseptically inoculated at 5 nodes / kilner jar and incubated for four weeks at a light intensity of 3000 lux for 16 hours photoperiod at 20°C. culture media consisted of Murashige and Skoog (MS) media supplemented with different growth regulator combinations of O.Olmg/1 GA3 and 0.001 mg/I kinetin. The procedures were repeated thrice after inoculation to remove shoots from the culture vessels to divide into sections containing several nodes which were inoculated onto fresh medium and repeated every three weeks for three months.Item Micropropagation of Different Potato Cultivars in Upscaling Seed Potato Programme in Kenya(2013) Otieno, S.; Muthoni, J.; Lung'aho, C.; Mbiyu, M.; Oyoo, J.; Onditi, J.; Nyongesa, M.; Kabira, J.; Kenya Agricultural Research Institute - National Potato Research Centre,Scarcity of good quality seed is a major constraint in potato (Solanum tuberosum) production coupled by high expensive gelling agent used in the micropropagation to produce clean pre-basic seed in the country. A study was set out to compare the performance of liquid and solid media in potato micropropagation using 10 potato cultivars. Sections of potato plantlet containing one node were aseptically inoculated at 5 nodes/kilner jar and incubated for four weeks at a light intensity of 3000 lux for 16 hours photoperiod at 20 CC. The culture media consisted of Murashige and Skoog (MS) media supplemented with different growth regulator combinations of 0.01 mg/l GA3 and 0.001 mg/l kinetin. The procedures were repeated thrice after inoculation to remove shoots from the culture vessels to divide into sections containing several nodes which were inoculated onto fresh medium and repeated every three weeks for three months. The experiment was laid out as a two-factor randomized complete block design replicated four times and was repeated three times. Results showed that there was no difference (P≤ 0.05) between the liquid and the solid media regardless of the type of growth regulator used for the parameters shoot length, number of roots and number of nodes. Solid media was the best for development of complete plantlets and multiplication from meristem tips while liquid media supplemented with 0.01 mg/l GA3 and 0.001 mg/l kinetin for sub-culturing produced plantlets with the highest vigour with respect to shoot height, root length and number of nodes. There was variability of the cultivars in their response to the micropropagation media studied suggesting that there is need to develop a cheap micropropagation protocol that may be suitable for most Kenyan potato cultivars.Item Simple Tips to Achieve Proper Seed and Ware Potato Storage(Kenya Agricultural & Livestock Research Organization, (KALRO), 2017) Otieno, S.; Kipkoech, D.; Onditi, J.O.; Mbiyu, M.; Oyoo, J.; Nyongesa, M.; Kenya Agricultural and Livestock Research OrganizationTo ensure long shelf-life of ware potatoes, tubers need to be stored in crates or pilled in a cool dry place to ensure regular supply during demand and/or attract high prices.
