Browsing by Author "Nyongesa, M."
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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 Dutch Robijn: A Potato Variety with Excellent Crisping and Mashing Quality(Kenya Agricultural & Livestock Research Organization, 2013) Onditi, O.J.; Karinga, J.K.; Nderitu, S.W.K.; Nyongesa, M.; Mbiyu, W.M.; Oyoo, J.; Otieno,S.; Kenya Agricultural and Livestock Research OrganizationPlant description. This is a relatively short potato variety (just about 0.8 metre in height) with strong erect stems, dark green medium sized leaves and very rare light pink flowers. Potential yield: Ranges between 20-30 t/ha (72-110 bags if packed in 110 kg bags per acre) under sufficient rainfall and recommended crop production practices.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 Kerr’s Pink: An Early Maturing 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.; Kenya Agricultural and Livestock Research OrganizationThis is a relatively short potato variety, which is (approximately 0.5 metres with thick to medium stem, dark green leaves and white flowers.Ranges between 25-30 t/ha (90-110 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.; 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 Minimizing Fungicides by Alternating Formulations and Intervals to Improve Potato Blight Management and Farm Returns(African Crop Science Journal, 2023-04-01) Kilonzi, J.; Nyongesa, M.; Pwaipwai, P.; Oyoo, J.; Mafurah, J.; Kenya Agricultural and Livestock Research Organization ; Egerton UniversityLate blight (Phytophthora infestans) is one of the most devastating and economic disease impacting both ware and the seed potato industry. The disease causes huge crop losses, and its management attracts heavy expenses. Efficacy successes in chemical management, as opposed to biofungicides, has resulted in the development of a number of fungicide formulations to counter emergence of chemically insensitive P. infestans strains. The objective of this study was to evaluate the efficacy and cost-benefits of applying different fungicides in alternate; while varying the spray intervals to manage potato blight and improve on net farm returns. A survey was conducted in Nyandarua County in Kenya, using a structured questionnaire, administered to potato farmers. Milraz®(Propineb 700 g kg-1+ Cymoxanil 60 g kg-1), Ridomil®(Metalaxyl 4%+ mancozeb 64%) and Mistress 72®(Cynamoxil 4%+ Mancozeb 64%) were used in vitro and field experiments. Plated pea agar and detached leaflets were amended with the fungicides at concentrations of 0, 35, 70 and 100% of the manufacturers recommended rate before inoculating with P. infestans. In the field experiment, the fungicides were applied at intervals of 7, 14 and 21 days spray as single, two or three fungicides in alternations. Results showed that, mycelial and blight lesion growth was curtailed by concentrations of 70 and 100%; while 35% concentration of the fungicides reduced mycelial growth and lesion size by 53 and 2%, respectively. In the field experiment, there were no yield and AUDPC differences (P< 0.05) among the fungicides and their combinations. However, spraying the fungicides at weekly and bi-weekly intervals gave the highest yields of 17.65 and 16.4 t ha-1, compared to tri-weekly and unprotected plots that recorded 7.93 and 0.43 t ha-1, respectively. In addition, application of triple fungicides in alternation reduced late blight severity by 51%; while application of two fungicides in alternation reduced severity by 39% compared to single fungicide application (21%) on average. Maximum net benefit ratio was observed on plots protected using three fungicides (31.58); followed by two fungicides applications (26.81) applied biweekly in alternate relative to single fungicide applied weekly.Item Salt Tolerance of Two Potato Cultivars(African Journal of Education, Science and Technology, 2023-03) Rutto, A.; Thagana, W.; Nyongesa, M.; Kenyatta University ; Kenya Agricultural and Livestock Research OrganizationPotato (Solanum tuberosum L.) is one of the leading crop plants used for food production globally. The varieties that are presently grown are greatly hampered productively by increased salinity. The repercussion of salinity stress on productivity of potato plant was assessed using Shangi and Unica varieties sourced from KALRO Tigoni. Potato tubers were grown in 4L polybags packed with coco peat media and kept under greenhouse conditions. A two-factorial experiment in CRD was used with factors being cultivar and treatments of salt concentrations. Twenty-one days after emergence, plants were subjected twice in seven days to six different treatments of salinity levels (0, 6, 8, 10, 12, 14dS/m) of NaCl in solution form prepared. Measurements of height 30 days after start of salt application, tuber weight and number at harvest were recorded. At 0dS/m, the two varieties performed optimally. Salt concentration significantly affected cultivars performance in height, weight of tubers and number of tubers. Both shangi and Unica demonstrated better performance at between 6-8 dS/m with less yield decrease than the other salt concentration. At 10dS/m, Unica’s performance was better as opposed to Shangi that was adversely affected by the salts though Shangi’s performance decreased at a higher rate with increase in salt.(Table 3). The tubers had the highest weight at 6 dS/m concentration while Unica species produced tubers with the highest weight.(16g). Unica therefore performed better than Shangi indicating that it’s more tolerant to salinity than Unica. This research was meant to identify a salt tolerant potato cultivar between Shangi and Unica which can be used for breeding for salt tolerant varieties. It was thus found that Unica is salt tolerant as had been found in other previous studies. Unica therefore is recommended for planting by farmers who cultivate in fields affected by high salinity incidences. In addition, Unica genes are recommended to breeders who can use them for breeding purposes to breed for salt tolerant 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.
