Mahatma, LalitPawar, Dayaneshwar Madhukarrao2018-08-232018-08-232010-07PAWAR DNYANESHWAR MADHUKARRAO_43782http://krishikosh.egranth.ac.in/handle/1/5810067089Mungbean (Vigna radiata (L.) Wilczek) is one of the important pulse crops primarily grown for food in India. During the survey, occurrence of Mungbean Yellow Mosaic Virus (MYMv) in mungbean was noticed in serious proportion causing heavy losses in Navsari, Surat and valsad districts;. Cultivars GM-4 and K-851 were found more severely affected at the flowering stage during summer season . Considering the seriousness of the problem, the present investigation was carried out on transmission and detection of virus. Roving field surveys were under taken in and around Navsari , Surat and Val sad districts, the total 16 locations to find out occurrence of the Mungbean Yellow Mosaic Virus (MYMv) during summer, 20 I O. The MYMv incidence increases with on increase in crop stages. Crop at the first trifoliate leaf stage was 08-12 per cent, second trifoliate leaf stage was 16-20 per cent and before flowering stage 4 I to 55 % incidences were reloaded and at the time of maturity stage showed 65-76 per cent incidence of MYMv. Fields of Sugarcane Research Station, NAU, Navsari farm were observed periodically. Three popular varieties of mungbean viz., K-851, GM-3 and GM-4 were sown in the field. None of the variety showed resistance against the disease and 75 to 100 per cent incidence was reloaded at the time of crop maturity. Among these, K-8S1 showed cent per cent MYMV incidence. The disease appeared in the field as small scattered yellow to golden yellow colour flecks on the infected leaves. These were scattered on the entire leaves and were more concentrated near the leaf venation. The severity of the symptoms could be seen in the newly emerging leaves, where in case of high susceptibility, cent per cent area of the leaf turned yellow. The symptoms could be observed on all the green coloured aerial parts of the plants including cotyledon leaf, trifoliate leaves, stem, petiole, flower part, pod and seeds. Infected plant remained stunted with few pods of small size and shrivelled seeds. The peR based diagnostic protocol was standardized to amplify viral DNA, six different primer pairs were used. Presence of DNA-A and DNA-8 molecules of the virus could be detected by the different sets of the primers. Self designed primer pair, LM-20F + LM-20R was best and replicative. Therefore, the same primer pair was used for the different diagnostic and localization purpose throughout the study. The virus was not found to be transmitted by seeds, mechanical sap and aphid in the susceptible plants. Whitefly (Bemisia tabaci, Gennadius) could acquire virus i~ 30 minutes of acquisition feeding and similarly could inoculate in 30 minutes of inoculation feeding period. There was effect of fasting on the transmission of virus. for cent percent virus transmission, whiteflies needs 6 hours of acquisition and inoculation feeding period. MYMV could be detected from the sepal, standard petal, wing petal, keel petal and androecium . However, MYMV could not be detected from gynoecium. Among the parts of seeds, MYMV could be detected from the pod , seed coat and cotyledon. However, presence of MYMV could not be detected from embryo of the seed . From the results , it is concluded that the seeds act as a passive source of primary inoculation and may be termed as passive transmission of the disease or virus through seeds . Presence of MYMV in the callus induced from the infected cotyledon could be detected. This is the first report of the detection of any Begomovirus from the seeds or any part of the seeds. Further, the virus could be multiplied (cultured) artificially in the laboratory condition.ennullThesis