Resistance to sweet potato virus disease (SPVD) in wild East African Ipomoea

Karyeija, R. F.; Gibson, R. W.; Valkonen, Jari P. T.

doi:10.1111/j.1744-7348.1998.tb05800.x

Cited by 35 publications

(27 citation statements)

References 9 publications

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“…Many East African sweet potato cultivars are resistant to SPFMV (Gibson et al 1998;Mwanga et al 2002b). Resistance is broken when the varieties are co-infected with SPCSV (Karyeija et al 1998a;Mwanga et al 2002b). There have been eVorts toward developing a transgenic sweet potato resistant to SPVD through resistance to SPFMV both in Kenya and other parts of the world (Okada et al 2001;Wambugu 2003).…”

Section: Introductionmentioning

confidence: 98%

“…The landraces have large diVerences in susceptibility to SPVD, and good sources of resistance are present in local germplasm (Aritua et al 1998a). The impact of SPVD has been reduced by the use of resistant cultivars and landraces (Aritua et al 1998b;Karyeija et al 1998a). However, resistance has been associated with relatively late maturing, low-yielding genotypes (Aritua et al 1998b).…”

Section: Introductionmentioning

confidence: 98%

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Identification of molecular markers associated with sweet potato resistance to sweet potato virus disease in Kenya

2007

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Sweet potato virus disease (SPVD), a result of the co-infection of whiteXy transmitted Sweet potato chlorotic stunt virus (genus Crinivirus, family Closteroviridae) and the aphid transmitted Sweet potato feathery mottle virus (genus Potyvirus, family Potyviridae), is the most destructive disease of sweet potato in East Africa. A study was conducted to establish if genotypes identiWed as resistant or susceptible to SPVD in Kenya could be distinguished using molecular markers. A total of 47 unrelated sweet potato genotypes were selected from germplasm collections and classiWed into two phenotypic groups as resistant or susceptible to SPVD. Genotype selection was based on disease severity or days to symptom development in plants following graft inoculation.AmpliWed fragment length polymorphism (AFLP) marker proWles were generated for each individual and used in association studies to identify markers suitable for classifying the two pre-deWned phenotypic groups. Analysis of molecular variance showed signiWcant (P < 0.002) variation between the two groups using 206 polymorphic AFLP markers. Discriminant analysis and logistic regression statistical methods were used to select informative markers, and to develop models that would classify the two phenotypic groups. A training set of 30 genotypes consisting of 15 resistant and 15 susceptible were used to develop classiWcation models. The remaining 17 genotypes were used as a test set. Four markers, which gave 100% correct classiWcation of the training set and 94% correct classiWcation of the test set, were selected by both statistical methods.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

Identification of molecular markers associated with sweet potato resistance to sweet potato virus disease in Kenya

2007

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“…Sweet potato can adapt to a wide range of environmental conditions and can be grown on marginal areas with poor soils of limited fertility and inadequate moisture. The production of sweet potato in Kenya has been low due to several abiotic (drought, low rainfall, poor soils) and biotic (insect pests and diseases) factors [5,6,7]. Among the major biotic constraints for sweet potato production insect pests are recoded as the most important [8].…”

Section: Introductionmentioning

confidence: 99%

A Survey of farmers’ perceptions and management strategies of the sweet potato weevil in Homa Bay County, Kenya

Ochieng¹,

Githiri²,

Nyende³

et al. 2017

AJFAND

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Sweet potato (Ipomoea batatas L.) is one of the most widely grown root crops worldwide. In Africa, it is grown in small plots by poorer farmers. Production of the crop is extremely low in Kenya as compared to other African countries due to the existence of common insect pests. Sweet potato weevil (Cylas spp.) is known as the biggest pit fall for production and productivity of the crop in the country. This study sought to determine the opinion of sweet potato farmers concerning sweet potato resistance to Cylas spp. and determine control strategies employed by sweet potato farmers in managing the pest. The study also sought to determine the sweet potato production constraints faced by the farmers in Homa Bay County, Kenya. The study was conducted using a Participatory Rural Appraisal approach in which 269 farmers in the County were interviewed on the sweet potato varieties with field resistance to Cylas spp., the crops' production constraints (with emphasis on damage by Cylas spp.) and farmers' control strategies in regard to the weevil. Data were also collected from the farmers whose sample size was determined using the table on sample size selection and standardization equation. Data were analysed using descriptive statistical techniques that were frequencies, percentages and standard errors. The study established that majority of the farmers from Rachuonyo (89.7%) and Ndhiwa (91.9%) were not aware of any variety that had field resistance to Cylas spp. However, 10.5% of the farmers in Rachuonyo and 8.1% of the farmers in Ndhiwa identified nine varieties which have shown relative field resistance to root damage by Cylas spp. The varieties that were identified to be resistant to Cylas spp. by farmers in Rachuonyo were Kalamb Nyerere, Tombra, Sinia, Odinga, Kemb 10, Wera and Zapallo. However, the varieties that were identified to be resistant to Cylas spp. by farmers in Ndhiwa were Amina, Mugande and Ndege Oyiejo. Further, the findings revealed that Cylas spp. was the most problematic pest by 90.3% and 96.8% of households in Rachuonyo and Ndhiwa, respectively. Majority (64.5%) of the farmers in Ndhiwa did not use any methods to manage Cylas spp. However, farmers in Rachuonyo (26.2%) and Ndhiwa (15.3%) preferred re-ridging during weeding as a management strategy in regard to Cylas spp. These findings reiterate the importance of the sweet potato weevil in rural sweet potato farming systems and thus innovative management strategies are necessary.

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“…This was revealed by Gibson et al (1998) and the different levels of tolerance to viruses (Valverde et al 2007) were influenced by temperature, plant age and light intensity Other symptoms observed on foliage indicated nutrient deficiency at mid storage root development and towards the final harvest. The nutrient disorders observed on foliage growth included, zinc and iron in L3 on young leaves, zinc in L49, iron and copper in Vekeoli, and iron in LD02.…”

Section: Varietal Effects On Marketable and Unmarketable Roots At 120mentioning

confidence: 99%

“…There are more than twenty-two sweetpototato viruses known to Transmission of virus disease is mainly by insects (Byamukama et al 2004;Loebenstein et al 2003;Schaefers & Terry 1976;Valverde et al 2004). Viruses are also spread through use of infected planting material which mostly occurs due to human activities (Gibbs et al 2008;Karyeija et al 1998). The virus status and nature of the diseases have been studied and means to control using chemicals is costly and not very effective (Sharaf 1984).…”

Section: Introductionmentioning

confidence: 99%

Studies on propagation materials and growing conditions for sweetpotato [Ipomoea Batatas (L.) Lam] production

Atu¹

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A thesis submitted for the degree of Master of Philosophy atThe University of Queensland in 2013 School of Agriculture and Food Sciences i ABSTRACTSweetpotato propagation is cultivated through use of sprout (slip) or vine cutting. Production of sprout is increased by best selection of storage root sizes to optimize growth and yield.Cultivars of different storage root sizes produced variable numbers of sprouts, varying in length and thickness and to explore this four storage root sizes in an open field bed were trialed. Beauregard and Northern Star storage roots selected from the large, medium, smallmedium and small storage root category sown in bed and sprouts at three length classes were first measured 47 days after sowing. The next three harvests were measured at 21 days interval while the fifth harvest was at 44 days after the fourth, calculated from the Growing Degree Days (GDD) units. Beauregard produced significantly higher number of sprout at >20 cm but fewer > 35 cm length than Northern Star. The sprout length 20 -35 cm class increased for both varieties after Harvest 1 but Beauregard tended to increase less for this class than Northern Star with progressive harvests. In the fifth harvest 20 -35 cm length class for both varieties had reduced although Northern Star produced more for this class than Beauregard. A significantly higher number of sprouts were produced by large root but not significantly different from the medium root. Sprout categories for < 20 and 20 -35 cm were greater for large and medium roots than smaller roots. The thickness of sprout progressively decreased in numbers as storage roots size decreased. Sprouts longer than 20 cm are considered best propagation material for farmers and to achieve this within the best possible short period is an advantage to farmers.The experiment study on seven sweetpotato varieties for pathogen tested (PT) and nonpathogen tested (NPT) was investigated at 60 days after planting (DAP), 120 DAP and 220 DAP for yield differences. There was no significant difference (P < 0.05) for all varieties for early root growth at 60 (DAP). No significant difference was observed for PT and Non-PT for the marketable yield but a significant increase in non-marketable yield at 120 DAP and 220 DAP for PT and non-PT was presumably due to virus infection.The number of marketable storage root production declined as the crop grew older but the opposite trend occurred for the non-marketable yield which increased three fold in the final harvest compared to the previous harvest. Northern Star produced the highest number and weight of marketable and non-marketable roots compared to the other six varieties.ii LD02 and Beauregard were the second best varieties in terms of marketable roots while L49, Vekeoli and Lola Tonga had the least potential. Northern Star followed by Beauregard and LD02 proved their supremacy by their ability to partition dry matter to bulk storage root.Beauregard was the only variety observed with SPFMV infection in the foliage.High soil temperatures affected the...

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Resistance to sweet potato virus disease (SPVD) in wild East African Ipomoea

Cited by 35 publications

References 9 publications

Identification of molecular markers associated with sweet potato resistance to sweet potato virus disease in Kenya

Identification of molecular markers associated with sweet potato resistance to sweet potato virus disease in Kenya

A Survey of farmers’ perceptions and management strategies of the sweet potato weevil in Homa Bay County, Kenya

Studies on propagation materials and growing conditions for sweetpotato [Ipomoea Batatas (L.) Lam] production

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