The Genus Striga (Scrophulariaceae) in Africa

Mohamed, Kamal I.; Musselman, Lytton J.; Riches, C.

doi:10.2307/2666132

Cited by 87 publications

(91 citation statements)

References 7 publications

(11 reference statements)

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“…(Matusova et al, 2004), a very low germination rate (<10 %) has been found in the absence of hosts in all cases. The system of chemical recognition assures that germination begins only when the root of the potential host is available in the immediate vicinity (Mohamed et al, 2001;Joel et al, 2011). The formation of haustoria also occurs in answer to chemical and tactile stimuli provided by the host roots (Westwood et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

SEED GERMINATION AND PLANT DEVELOPMENT IN Escobedia grandiflora (OROBANCHACEAE): EVIDENCE OF OBLIGATE HEMIPARASITISM?

Medina

Ruiz²

2015

Acta Biol. Colomb.

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Root parasitic plants can be facultative or obligate. Facultative parasites are able to complete their life cycle and their seeds can germinate without a host. Escobedia grandiflora is a poorly studied species in spite of its ancestral importance as dye of foods and medicinal use. The present study evaluates the states of seed, seedlings and mature plants, under presence and absence of possible hosts, for inferring the type of parasitism exhibited by E. grandiflora. Seeds were evaluated using two conditions each of light (12 and 0 hours) and temperature (20 ºC and 25 ºC); percentage germination, and germination speed were determined. The seeds did not require a host to germinate, as is typical of facultative parasitic plants. Percentage of germination varied between 66 % and 85.3 % and was not affected by light or temperature although germination speed was greater at 25 ºC. Larger seeds had a higher percentage of germination and produced larger seedlings. The seedlings planted without a host did not survive, while those planted with Paspalum notatum had a 45 % survival rate, demonstrating that this is a critical stage of development, even with a host. Escobedia grandiflora plants sowed with grasses began the reproductive stage at the 28 th week, and those planted with Pennisetum purpureum showed better performance, expressed in more haustoria, higher dry matter of total plant, rhizome and aerial stems. Plants sowed alone lived for more than six months, but they did not produce flowers or fruits. According to the behavior of seedlings and plants, E. grandiflora is an obligate parasite.Keywords: Escobedia, obligate hemiparasite, parasitic plant, root parasitism, seed germination. RESUMENLas plantas parásitas de raíces pueden ser facultativas u obligadas, las primeras pueden completar su ciclo de vida y sus semillas pueden germinar sin un hospedero. Escobedia grandiflora es una especie poco estudiada, a pesar de su importancia ancestral como colorante de alimentos y uso medicinal. Este estudio evaluó los estados de semilla, plántula y planta adulta, en presencia y ausencia de posibles hospederos para inferir sobre su tipo de parasitismo. En las semillas se evaluaron dos condiciones de luz (12 y 0 horas) y temperatura (20 ºC y 25 ºC), el porcentaje y velocidad de germinación. Las semillas no requirieron la presencia del hospedero para germinar. El porcentaje de germinación osciló entre 66 y 85,3 % y no fue afectado por la luz o la temperatura, aunque la velocidad de germinación fue mayor a 25 ºC. Las semillas con mayor tamaño presentaron mayor porcentaje de germinación y produjeron plántulas más grandes. Las plántulas sembradas sin hospedero no sobrevivieron, mientras que las sembradas con Paspalum notatum, tuvieron una sobrevivencia del 45 %, evidenciando que este estado es crítico, aún con hospedero. Las plantas de Escobedia grandiflora sembradas con pastos, iniciaron la etapa reproductiva en la semana 28, y aquellas sembradas con Pennisetum purpureum presentaron más haustorios, y mayor materia seca en la ...

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Section: Introductionmentioning

confidence: 99%

SEED GERMINATION AND PLANT DEVELOPMENT IN Escobedia grandiflora (OROBANCHACEAE): EVIDENCE OF OBLIGATE HEMIPARASITISM?

Medina

Ruiz²

2015

Acta Biol. Colomb.

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“…The herbarium and literature data provided information on the geographical distribution of different parasitic weed species (e.g. Mohamed et al 2001;Rodenburg et al 2014Rodenburg et al , 2015. We found out that Striga species are spread over 33 African countries that produce rice in the rainfed uplands where these species can be encountered.…”

Section: Evaluating the Institutional Dimension Of Parasitic Weeds Anmentioning

confidence: 79%

Systems approaches to innovation in pest management: reflections and lessons learned from an integrated research program on parasitic weeds in rice

Rodenburg¹,

Schut²,

Demont

et al. 2015

International Journal of Pest Management

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This paper provides a retrospective look at a systems-oriented research program, on the increasing occurrence of parasitic weeds in rainfed rice in sub-Saharan Africa, to qualitatively assess merits and identify challenges of such approach. We gained a broad contextual overview of the problem and different stakeholders' roles, which enabled identification of entry points for innovations in parasitic weed management. At the crop level parasitic weed infestation is associated with poor soil fertility and water management. Farmers' infrequent use of inputs to control them was caused by various factors, ranging from fears of undesired side effects (agronomic) to a lack of quality control of products (institutional). Furthermore, there may be enough extension agents, but they lack the required training on (parasitic) weed management to provide farmers with advice, while their organizations do not provide them with the necessary means for farm visits. At even higher organizational levels we observed a lack of coherent policies on parasitic weed control and implementation of them. Merits and challenges of an integrated multi-stakeholder and multi-level research project are discussed.

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“…This is where it infects the major cereal crops: maize, sorghum, rice and finger millet. S. asiatica is predominantly found in the coastal region infecting upland rice (Gethi et al, 2005) and exists sporadically in Isiolo, Busia and Naivasha (Mohamed et al, 2001). Striga gesneriodes, a species adapted as a pest of legumes has a wide geographical distribution in Kenya compared to the other species.…”

Section: Introductionmentioning

confidence: 99%

Effect of Striga hermonthica (Del.) Benth on Yield and Yield Components of Maize (Zea mays L.) Hybrids in Western Kenya

Mbogo¹,

Dida²,

Owuor³

2016

JAS

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Striga hermonthica (Striga) weed is widespread in Kenya, where it causes significant cereal crop losses, particularly when susceptible varieties are grown. The use of maize (Zea mays L.) genotypes that support reduced Striga hermonthica emergence can form an important basis for developing resistant cultivars. The objective of this study was to evaluate the response of diverse maize hybrids to Striga weed infestation and to identify high yielding and stable hybrids. Six experimental maize hybrids and three commercial hybrid checks (DK8031, PhB3253 and H513) were evaluated under Striga and Striga free conditions at Nyahera and Maseno in western Kenya in 2011 and 2012 growing seasons. The data collected included grain yields and other yield components; emerged Striga counts and Striga damage rating (on a scale of 1-5) at 8 and 10 weeks after planting (WAP). Significant differences (P < 0.05) were observed in grain yield and yield components; emerged Striga counts and Striga damage syndrome in both years. Negative correlation (r) was observed between emerged Striga and yield as well as between Striga damage ratings and yield. Maseno experimental hybrids produced much better grain yields and were more stable compared to commercial varieties under Striga infestation and in Striga free fields. Deployment of the tolerant/resistant high yielding well adapted hybrids coupled with other management options such as rotation with legumes and cultural practices could possibly help in depletion of Striga seed bank in the soils in western Kenya. EH12 and EH14 maize hybrids were formally released for commercialization in the Striga endemic areas of western Kenya.

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The Genus Striga (Scrophulariaceae) in Africa

Cited by 87 publications

References 7 publications

SEED GERMINATION AND PLANT DEVELOPMENT IN Escobedia grandiflora (OROBANCHACEAE): EVIDENCE OF OBLIGATE HEMIPARASITISM?

SEED GERMINATION AND PLANT DEVELOPMENT IN Escobedia grandiflora (OROBANCHACEAE): EVIDENCE OF OBLIGATE HEMIPARASITISM?

Systems approaches to innovation in pest management: reflections and lessons learned from an integrated research program on parasitic weeds in rice

Effect of Striga hermonthica (Del.) Benth on Yield and Yield Components of Maize (Zea mays L.) Hybrids in Western Kenya

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