Studies on the physiological effects of viruses on sweet potato yield in Kenya

Njeru, R. W.; Mburu, Mary W. K.; Cheramgoi, E.; Gibson, R. W.; Kiburi, Z M; Obudho, Elias Otieno; Yobera, D.

doi:10.1111/j.1744-7348.2004.tb00360.x

Cited by 43 publications

(24 citation statements)

References 14 publications

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“…However, the situation was worsened when SPCSV co-infected with SPFMV resulted in yield losses ranging from 60% to 95% similar to that reported earlier (Sheffield 1957;Schaefers and Terry 1976;Milgram et al 1996;Gibson et al 1998;Gutierrez et al 2003). The reduced root yield in sweetpotato has been attributed to decrease in size of photosynthetic organs resulting from severe stunting and other symptoms of SPVD due to synergistic interaction (Hahn et al 1981;Njeru et al 2004).…”

Section: Discussionsupporting

confidence: 73%

“…The yield loss ranged from 14% to 52% in all the cultivars tested in the two locations. In other studies, yield losses of between 15% and 88% have been reported (Milgram et al 1996;Gibson et al 1998;Gutierrez et al 2003;Njeru et al 2004;Untiveros et al 2007). However, the situation was worsened when SPCSV co-infected with SPFMV resulted in yield losses ranging from 60% to 95% similar to that reported earlier (Sheffield 1957;Schaefers and Terry 1976;Milgram et al 1996;Gibson et al 1998;Gutierrez et al 2003).…”

Section: Discussionmentioning

confidence: 81%

“…Studies in other countries on the effect of SPFMV on yield of sweetpotato cultivars are contradictory. Some studies have reported no effects on yield of storage roots and vines in comparison with healthy plants (Milgram et al 1996;Clark and Hoy 2006), and other studies have reported SPFMV-infected plants producing better yield than the healthy control (Gutierrez et al 2003), while others have reported yield reduction of up to 46% (Gibson et al 1997;Mukasa 2004;Njeru et al 2004;Domola et al 2008). Due to this contradictory evidence, there is a need to further investigate the effect of SPFMV on Ugandan sweetpotato cultivars to design an effective management system in Uganda.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Sweet Potato Feathery Mottle Virus and Sweet Potato Chlorotic Stunt Virus on the Yield of SweetPotato in Uganda

Adikini

Mukasa

Mwanga

et al. 2015

Journal of Phytopathology

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Sweet potato feathery mottle virus (SPFMV) and Sweet potato chlorotic stunt virus (SPCSV) are the most common viruses infecting sweetpotato in Uganda. Field plots planted with graft inoculated plants of virus-free cultivars Beauregard, Dimbuka, Ejumula, Kabode and NASPOT 1 were used to assess the effect of SPFMV and SPCSV on yield and quality of sweetpotatoes in two agro-ecologies. SPFMV spreads rapidly to control plots at Makerere University Agricultural Research Institute Kabanyolo (MUARIK), and these plots had similar yields to those singly infected with SPFMV but at the National Semi Arid Resource Research Institute (NaSARRI) where SPFMV spreads slowly, plots infected with SPFMV yielded 40% less than the control. Recovery from SPFMV appeared to be more frequent at NaSARRI than at MUARIK. Infection by SPCSV alone resulted in yield losses of 14-52%, while mixed infections of SPFMV+SPCSV resulted in yield losses in both locations of 60-95% depending on the cultivar. SPCSV and mixed infections of SPFMV+SPCSV also reduced the number of roots formed as well as the diameter of the roots, resulting in a greater length to diameter ratio compared to the healthy control. This study, therefore, confirms that both SPFMV and SPCSV, both singly and when mixed, can reduce yield, the extent depending on the cultivar. To mitigate the effect of these viruses, farmers should use clean planting materials of resistant varieties.

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Section: Discussionsupporting

confidence: 73%

Section: Discussionmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of Sweet Potato Feathery Mottle Virus and Sweet Potato Chlorotic Stunt Virus on the Yield of SweetPotato in Uganda

Adikini

Mukasa

Mwanga

et al. 2015

Journal of Phytopathology

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“…SPCSV causes severe symptoms (SPVD) when co‐infecting with SPFMV, and clones which become wholly or largely infected will be discarded by farmers (Gibson et al ., ), so established landraces where SPVD is prevalent are more resistant to it than ones in areas where it is rare (Bua et al ., ). They will also be inoculated by aphids bearing SPFMV (Wambugu, ) and other symptomless viruses, especially where SPCSV is common (Milgram et al ., ; Aritua et al ., ), causing loss of yield (Gibson et al ., ; Mukasa, ; Njeru et al ., ) if permanently infected, and again rejected if yield is badly affected. In line with this, many symptomless plants of landraces in East Africa are virus‐free or contain only a single virus (Gibson et al ., , ; Mukasa et al ., ; Ateka et al ., ; Tairo et al ., ; Aritua et al ., ; Njeru et al ., ).…”

Section: Breeding Sweetpotato Cultivars Especially For Virus Resistancementioning

confidence: 99%

Degeneration in sweetpotato due to viruses, virus‐cleaned planting material and reversion: a review

Gibson

Kreuze

2014

Plant Pathology

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This review examines viral degeneration in sweetpotato in different regions of the World, particularly that caused by Sweet potato chlorotic stunt virus (SPCSV) and Sweet potato feathery mottle virus (SPFMV), comparing impacts on yield in single and complex infections of all the major viruses affecting the crop. How cultivars are generated and virus resistance are also covered, especially for Africa. The synergistic (SPCSV + SPFMV) sweet potato virus disease (SPVD) is amongst the most dramatic diseases of sweetpotato but its overall yield impacts may not be as high as is generally assumed. It is constrained by resistance, roguing and selection of symptomless planting material. Instead, the cumulative impact of individual and combinations of symptomless viruses may be globally greater. These include sweepoviruses and various potyviruses, of which the commonest is SPFMV. A number of aspects of virus‐cleaned planting stocks are identified, including reinfection rates, that need investigating before their use is considered as sustainable in developing countries. Popular East African cultivars appear to sustain their long‐term survival by reverting from symptomless infection. The likely biochemistry of this is discussed, and parallels are drawn with other crops. It is concluded that breeding for this attribute will be the best strategy for achieving long‐term control of most sweetpotato viruses.

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“…Viruses can cause storage roots yield losses of up to 90% (Clark & Valverde 2001;Njeru et al 2004). Virus infection has also had impact on cultivar decline (Bryan et al 2003b;Clark et al 2002;Lewthwaite et al 2011) and quality of storage root was also claimed to be influenced by virus infection (Lee et al 2007).…”

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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Studies on the physiological effects of viruses on sweet potato yield in Kenya

Cited by 43 publications

References 14 publications

Effects of Sweet Potato Feathery Mottle Virus and Sweet Potato Chlorotic Stunt Virus on the Yield of SweetPotato in Uganda

Effects of Sweet Potato Feathery Mottle Virus and Sweet Potato Chlorotic Stunt Virus on the Yield of SweetPotato in Uganda

Degeneration in sweetpotato due to viruses, virus‐cleaned planting material and reversion: a review

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

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