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| Response Of Groundnut Varieties To Groundnut Ringspot Virus (Grsv) In Western Kenya |
L W Murere, B Mukoye, H K Were and M Kollenberg
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Abstract:
Groundnuts (Arachis hypogea) is an annual legume crop grown by small holder farmers in Kenya for its economic and nutritive value. However, its yields have declined upto 680 kg ha-1 than its genetic potential of 1690 kg ha-1 attributed to pests and diseases. Viruses are among disease causing factors for yield reduction globally. Orthotospovirus include; Tomato spotted wilt virus (TSWV), Groundnut ringspot virus (GRSV), Impatien necrotic spot virus (INSV), Tomato yellow ring virus (TYRV) among others. Groundnut ringspot virus (GRSV) has been reported in South Africa, Ghana, Brazil, USA, Argentina and Canada infecting groundnuts, soy beans tomatoes, among others. GRSV Symptoms have been noted on groundnuts and other plants in Kenya but no report has been documented on occurrence of the virus and groundnuts varieties resistant to GRSV. The objective of this study was; to determine response of groundnut varieties to GRSV in western Kenya. Health tested seeds of ICGV-9991, Red Valencia, Homabay, ICGV-90704, ICGV-12991, CG7, ICGV-99019, SM99568 and ICGV-99048 groundnut varieties planted in 500ml pots of a mixture of sterilized loam, sand and organic manure at a ratio of 2:1:1 respectively in greenhouse to screen for resistance levels of groundnut varieties to GRSV. Positive isolates for GRSV obtained in a survey from western Kenya, were macerated and mechanically inoculated groundnuts genotypes. symptomatic development, observed and recorded at an interval of 5 days for 8 weeks. Leaf samples collected for serological analysis used polyclonal antisera against GRSV. screened groundnuts showed Homabay being more susceptible with incidence of 31 %, followed by ICGV-9991 with incidence of 28 %. SM99568 variety was tolerant to the virus. Varieties ICGV-90704, ICGV-99048 and ICGV-99019 were resistant to the virus. Some of screened plants for host range were symptomatic for the virus and tested positive for the virus. The study showed that GRSV occurs in surveyed counties of western Kenya, which is a big concern. Introgression of resistant genes into local groundnut varieties to gain resistance to the virus be done with urgency.
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