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Majlis Syarahan Perdana Penyelidikan MARDI
Sunday, August 01, 2010
Tajuk : The Battle Against Virus Diseases of Chilli in Malaysia: Can We Win?
Oleh : Dr. Mohamad Roff Mohd. Noor
Tarikh : 5/8/2010 (Khamis)
Masa : 2 petang - 4.30 petang
Tempat : Dewan Kuliah Utama, Pusat Latihan MARDI
Utk maklumat lanjut, sila hubungi MARDI : 03-8943 7111
Oleh : Dr. Mohamad Roff Mohd. Noor
Tarikh : 5/8/2010 (Khamis)
Masa : 2 petang - 4.30 petang
Tempat : Dewan Kuliah Utama, Pusat Latihan MARDI
Utk maklumat lanjut, sila hubungi MARDI : 03-8943 7111
Chilli is considered as one of the most important vegetable crops in the tropics. The area cultivated with chilli in Malaysia is about 4000 ha. Diseases are often cited as the
major limiting factors in the cultivation of chilli. Viral diseases account for more losses in farmers’ fields than those caused by fungal and bacterial pathogens. These viruses can be spread by vectors, agricultural machineries, propagation tools and seeds.
The occurrences of virus diseases on chilli have been reported since the British administration. However, aetiological studies were being conducted only in the early
70s after the establishment of MARDI. A nationwide survey to determine the status of virus diseases on chilli was conducted from 1989-1993. Results of the survey showed that there were seven different viruses infecting chilli, namely
chilli veinal mottle virus, cucumber mosaic virus, tobacco mosaic virus,
tomato mosaic virus, tobacco etch virus, pepper veinal mottle virus
and tomato spotted wilt virus. Amongst them, chilli veinal mottle
virus and cucumber mosaic virus, transmitted by aphids, were the most prevalent. Whitefly, infestations on chilli surged in severity and importance during the late 1990s. This whitefly, Bemisia tabaci is the vector of geminiviruses. It is believed that changing climate conditions and cropping practices have
favoured the population increase of this vector. The successful spread of whiteflies and the concomitant establishment of geminiviruses have led to devastating losses in chilli crops. Most field grown chilli are found to be infected by two or more of these viruses and exhibit complex symptoms such as mosaic, mottling, leaf distortion, vein banding, yellowing and stunting causing not only reduction in yield but also deterioration of crop.
Curing virus infected plant is difficult because antiviral chemicals are not available presently. Hence, the current approaches employed to control virus diseases of chilli are, use of resistant cultivars, cultural measures, crop hygiene or eradication of diseased plants and alternative hosts, biological control using mild strain cross protection and insecticides to control the vectors. A number of research strategies have been initiated over the last decades to combat virus diseases of chilli. These include understanding virus pathosystem, preventing or delaying virus infection through ecological engineering and breeding for resistance by both conventional and pre-emptive breeding strategies. Several chilli accessions that are virus resistant have been identified. Our current research focuses on the introgression of this trait
into susceptible commercial cultivars. We are also embarking on work to develop high throughput diagnostic protocols to detect chilli viruses which can be used by extension agents and farmers to help to reduce viral inoculum pressure in chilli fields. To date, a vast array of information regarding management components of virus disease of chilli have been generated. The integrated management package developed will be of beneficial to chilli growers as a means of enhancing crop productivity to meet the increasing demands of a growing human population.
major limiting factors in the cultivation of chilli. Viral diseases account for more losses in farmers’ fields than those caused by fungal and bacterial pathogens. These viruses can be spread by vectors, agricultural machineries, propagation tools and seeds.
The occurrences of virus diseases on chilli have been reported since the British administration. However, aetiological studies were being conducted only in the early
70s after the establishment of MARDI. A nationwide survey to determine the status of virus diseases on chilli was conducted from 1989-1993. Results of the survey showed that there were seven different viruses infecting chilli, namely
chilli veinal mottle virus, cucumber mosaic virus, tobacco mosaic virus,
tomato mosaic virus, tobacco etch virus, pepper veinal mottle virus
and tomato spotted wilt virus. Amongst them, chilli veinal mottle
virus and cucumber mosaic virus, transmitted by aphids, were the most prevalent. Whitefly, infestations on chilli surged in severity and importance during the late 1990s. This whitefly, Bemisia tabaci is the vector of geminiviruses. It is believed that changing climate conditions and cropping practices have
favoured the population increase of this vector. The successful spread of whiteflies and the concomitant establishment of geminiviruses have led to devastating losses in chilli crops. Most field grown chilli are found to be infected by two or more of these viruses and exhibit complex symptoms such as mosaic, mottling, leaf distortion, vein banding, yellowing and stunting causing not only reduction in yield but also deterioration of crop.
Curing virus infected plant is difficult because antiviral chemicals are not available presently. Hence, the current approaches employed to control virus diseases of chilli are, use of resistant cultivars, cultural measures, crop hygiene or eradication of diseased plants and alternative hosts, biological control using mild strain cross protection and insecticides to control the vectors. A number of research strategies have been initiated over the last decades to combat virus diseases of chilli. These include understanding virus pathosystem, preventing or delaying virus infection through ecological engineering and breeding for resistance by both conventional and pre-emptive breeding strategies. Several chilli accessions that are virus resistant have been identified. Our current research focuses on the introgression of this trait
into susceptible commercial cultivars. We are also embarking on work to develop high throughput diagnostic protocols to detect chilli viruses which can be used by extension agents and farmers to help to reduce viral inoculum pressure in chilli fields. To date, a vast array of information regarding management components of virus disease of chilli have been generated. The integrated management package developed will be of beneficial to chilli growers as a means of enhancing crop productivity to meet the increasing demands of a growing human population.
