Varietal screening of mungbean cultivars for resistance/tolerance against insect pest under Terai Agro ecological zone of West Bengal

Abstract

Varietal preference of insect pests on mungbean germplasm was monitored under field\rconditions at Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, West Bengal\rduring the year 2012-13. Five genotypes/lines of mungbean germplasm were screened\ragainst insect pest and the germplasms were categorized into resistant and susceptible\rdepending upon severity of pest incidence. The differential responses of mungbean\rvarieties to insect pests were determined and none of the genotype/line was found to\rbe highly resistant to insect pest. During first season, Bireswar (WBM-34-1-1) had less\rsusceptibility to the attack of aphid and thrips gave highest (558.79 kg/ha) grain yield\rfollowed by Sukumar (WBM-29) with grain yield of 547.47 k/ha. Same trend was\robserved in case of aphid and thrips incidence during second season of screening.\rComparison of resistance among the five tested genotypes against whitefly showed\rthat the lowest (0.23) number of whiteflies per leaf was observed in Sonali (B-1), lower\rthan those of both Bireswar (WNM-34-1-1) and Sukumar (WBM-29), whereas, the\rhighest (1.33/ leaf) was observed in Panna (B-105) during first season. Whereas, in\rsecond season lowest (0.65/ leaf) whitefly incidence was observed on Sonali (B-1).\rhighest (1.83/ leaf) whitefly incidence was observed in Sukumar (WBM-29) followed\rby Panna (B-105) and Bireswar with 1.80 and 1.20 numbers per leaf, respectively. In\rcase pod borer incidence, the lowest (0.03) and the highest (1.18) larval population\rwere observed on cultivar Sonali (B-1) and Sukumar (WBM-29), respectively during\rfirst season. Whereas, during second season, among five varieties screened, highest\r(1.23/ plant) pod borer on Samrat (PDM 24-139) variety followed by Bireswar (WBM-\r34-1-1) and Panna (B-105) by recording pod borer incidence 0.93 and 0.73/ plant,\rrespectively. Lowest (0.22/plant) pod borer incidence observed on Sukumar (WBM-\r29) variety. Highest (2.20/plant) predatory coccinellid beetle was observed on Bireswar\r(WBM-34-1-1) followed by Sonali (B-1) and Samrat (PDM 24-139) with 1.89 and 1.25\rnumbers per plant, respectively. Lowest (0.84/ plant) lady beetle was observed on\rPanna (B-105) variety during first season. Whereas, during second season highest (4.17/plant) predatory coccinellid beetle was observed on Sukumar (WBM-29) followed by Sonali (B-1) and Samrat\r(PDM 24-139) with 2.59 and 1.95 numbers per plant, respectively. Lowest (0.88/ plant) lady beetle was observed on\rPanna (B-105) variety. Bireswar (WBM-4-34-1-1) and Sukumar (WBM-29) is fairly resistant to almost all pest of moong.\rBeside this varieties, remaining were neither fully resistant. Samrat (PDM 24-139) was heavily infested by aphids and\rthrips, which gave poor (902.31 kg/ha) yield. Among the cultivars, the highest (1108.25 kg/ha) yield potential was\robtained in Bireswar (WBM-4-34-1-1) and Sukumar (WBM-29) (1052.75 kg/ha). In contrast variety Panna (B-105) seed\rgave significantly lower yield (883.79kg/ha) in which Sonali (B-1) (B-1) and Samrat (PDM 24-139) (PDM 24-139) was\rnearer during second season. It can be concluded that insect pest infestation was strongly influenced by density of\rtrichome on plant surface. Dense (30.0 and 33.50/cm2) trichomes were observed on the leaves of Sukumar (WBM-29)\rduring first and second seasons, respectively. While trichome density was lowest (13.5 and 18.0/cm2) in Samrat (PDM\r24-139) had relatively higher aphid incidence during first and second seasons, respectively.