VARIETAL SCREENING OF OKRA AGAINST YELLOW VEIN CLEARING MOSAIC VIRUS (YVCMV)

Abstract

The research work was conducted in the experimental site of department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka-1207, to screen out the resistant cultivars of okra against Yellow Vein Clearing Mosaic Virus (YVCMV) transmitted by the white fly (Bemesia tabaci) during the period from March to July, 2014. Nine okra cultivars viz. BARI dherosh-1, Green finger, Anguli, Tower seed, Raja, Yuvraj, Shyamol bangla, Parvani kranti and Orka onamika were used as treatments. The screening of the selected cultivars was done based on different parameters like morphological features, yield and yield contributing characters and physiological features. In case of % disease incidence, the lowest disease incidence was found in cv Parvani kranti (9.74%) and the highest disease incidence was found in cv Yuvraj (81.14%) followed by Orka onamika (80.81%), while the other cultivars like Shyamol bangla, Raja, Anguli, Green finger and Tower seed showed high to moderate incidence respectively. In case of yield contributing characters like number of flowers per plant, number of fruits per plant comprising the yield, the highest yield per plant was recorded in Parvani kranti (616.0 gm) followed by BARI dherosh-1 (542.3 gm). The lowest yield per plant was recorded in cv Yuvraj (270.0 gm) preceded by cv Shyamol bangla (280.0 gm). The others gave moderate yield per plant. In case of physiological features, highest net chlorophyll content per plant was recorded in cv Parvani kranti (65.10 µ mol m -2 s -1 ) while the lowest in cv Anguli (38.17 µ mol m -2 s -1 ). In case of net assimilation rate, intercellular CO concentration, respiration rate and stomatal conductivity, the performance of the cultivar Parvani kranti was much better than the other cultivars against Yellow vein clearing mosaic virus (YVCMV). Parvani kranti showed better resistancy against YVCMV over others. 2