SCREENING OF DIFFERENT SWEET PEPPER LINES AGAINST CUCUMBER MOSAIC VIRUS AND CHILI VEINAL MOTTLE VIRUS

Rashid, M.H. , Khalequzzaman, K.M. , Alam, M.S., Uddin, S.A. and Green, S.K. 2007. Screening of Different Sweet Pepper Lines against Cucumber Mosaic Virus and Chili Veinal Mottle Virus. Int. J. Sustain. Crop Prod. 2(3):1-4 The experiment was carried out at the research farm of HRC, Bangladesh Agricultural Research Institute, Gazipur during 2000-2001 and 2001 2002. In ELISA test the pepper lines C-4, C-8 and Local check showed positive reaction to CMV and the line CV-6, CV-8 and Local check showed positive reaction to CVMV during 1999-2000 cropping season. The remaining lines showed negative reaction. But the line C4, C-8, C-9 and Local check showed positive reaction to CMV and CV-5, CV-6, CV-8 and Local check gave the positive reaction to CVMV during 2000-2001 cropping season. So, the sweet pepper lines C-1, C5, C-7, CV-1 and CV-22 may be used in breeding program for varietal improvement against the viruses. Key word: Screening, CMV, CVMV, ELISA, resistant, sweet pepper lines. INTRODUCTION Sweet pepper (Capsicum annuum L.) is one of the most important vegetable crops grown extensively throughout the world especially in the temperate countries (Manchanda and Singh, 1987). The pungency in pepper is due to an alkaloid known as capsaicine and peppers are characterized as sweet, hot or mild depending on capsaicine (C18H27O3N) content. It is rich sources of vitamins A and C (MacGillivary, 1961; Macrae et al., 1993). The crop is very sensitive to viral disease. The viral disease of sweet pepper is complex, more than one viruses attack simultaneously. Cucumber Mosaic Virus (CMV), Chili Veinal Mottle Potyvirus (CVMV), Mottle Potyvirus (CVMV) and Tomato Yellow Leaf Curl Virus (TYLCV) are most common viruses. In Nepal, the incidence of these virus complexes in pepper varied from 30-90% in different districts (Joshi et al. 1997). Most of the pepper fields exhibit complex symptoms of mosaic, mottle, leaf distortion, vein chlorosis and stunting causing considerable loss in yield and plant vigor. In Pakistan also virus complex in chili is considered as one of the most severe constraints in its production (Hameed et al. 1995). This crop suffers from a serious mosaic disease complex induced by potato virus Y (ordinary strain), CMV and many uncharacterized isolates of potyvirus group which are all transmitted by aphid vectors. Myzus persicae was the most efficient vector in transmitting the aforesaid viruses. Unfortunately, very little attempts were take to investigate the resistant source under Bangladesh conditions. The present investigations were taken to gather information on the resistant source. MATERIALS AND METHODS The experiment was carried out at the research farm of Horticulture Research Centre (HRC), Bangladesh Agricultural Research Institute (BARI), Gazipur during 1999 2000 and 2000 2001. Seeds were collected from Virology Laboratory of Asian Vegetable Research and Development Center (AVRDC), Taiwan. Seeds of sweet pepper were kept in cool room at 4C temperature for about four and half months, so, after taking out from the cool room, the seeds were kept for 3-4 hours at normal air temperature in the laboratory. To minimize tobamoviruses (TMV, ToMV and PMMV) seed infection, seeds were soaked in a 10% (w/v) solution of trisodium phosphate (TSP) for 30 minutes and transferred them to a fresh solution of 10% TSP for two hours and rinsed in running water for 45 minutes. They were then soaked in water for 24 hours in order to facilitate germination. Sowing medium on plastic tray was autoclaved at 120C for 2 hours and then cooled to the normal temperature by spreading the soil on the surface of the concrete floor. Each tray was then covered with one layer of newspaper and watered with a fine meshed sprinkler once in a day until emergence. Ten days after sowing when the seedling attained 3 leaf stage, then they were transferred to the poly bag each 12.75 X 10.15 cm size and filled with potting media comprising soil, compost and sand at the ration of 3:1:1. [ Eleven sweet pepper lines were screened against CMV and another eleven against CVMV. The lines were screened with pure isolates of CMV and CVMV by the following procedure: i) the percentage of virus infected plants was recorded. The inoculum was diluted 1:4 with 0.03 M Na2HPo4 buffer, p 7.0, containing 0.5% Na2So3, 1.7 g/liter Na-diethyldithiocarbamate and 0.1 g/liter activated charcoal. ii) 16 plants per lines were inoculated for CMV and CVMV at the five-leaf stage and iii) after four weeks the inoculated leaves were collected and send to AVRDC for ELISA test. Data were recorded on percent of infected plants, ELISA reaction, number of plants infected by ELISA and type of symptoms. Int. J. Sustain. Crop Prod. 2(3):1-4 (August 2007) © 2006 Green World Foundation (GWF) Int. J. Sustain. Crop Prod. 2(3) (August 2007) 2 RESULTS AND DISCUSSION Results on reaction of sweet pepper lines against cucumber mosaic virus (CMV) during 1999-2000 and 2000-2001 are presented in Table 1. In 1999-2000, the highest visually infected plants (80%) were observed in H-1 (local check). The lowest visually infected plants (10%) was recorded in C-5. But C-7, C-8 and C-9 did not show any visually infected plants. Sweet pepper lines C-4, C-8, C-9 and H-1 showed positive reaction to CMV by ELISA. In case of 2000-2001, the highest visually infected plants (100%) were obtained from H-1 (local check) and C-10 which were followed by C-11, C-6 and C-1. Sweet pepper lines C-4, C-8, C-9 and H-1 showed positive reaction to CMV by ELISA. The highest number of infected plants (3) was detected by ELISA in H-1 (local check). There were no infected plants by ELISA in C-1, C-2, C-5, C-6, C-7, C-9, C-11 and C-21. Mosaic symptoms were showed by C1, C-2, C-4, C-5, C-7, C-8, C-9, C-10, C-11 and H-1. Sweet pepper lines C-1, C-2 and C-4 showed leaf curling but C-21 did not show any symptom. Table 1. Reaction of sweet pepper lines against cucumber mosaic virus (CMV) during 1999-2000 and 2000-2001 1999-200