Pak. J. Agri. Sci., Vol. 45(4), 2008 SCREENING OF OKRA GENOTYPES AGAINST JASSID, AMRASCA BIGUTTULA BIGUTTULA (ISHIDA) (HOMOPTERA: CICADELLIDAE) Jamshaid Iqbal 1 , Mansoor ul Hasan 1 , Muhammad Ashfaq 1 , Shahbaz Talib Sahi 1 and Amjad Ali 2 1 University of Agriculture, Faisalabad 2 Ayub Agricultural Research Institute, Faisalabad The study was conducted for preliminary screening trial of 30 genotypes of okra for relative susceptibility/resistance against jassid, Amrasca biguttula biguttula (Ishida) during 2006. From these screening trials 3 genotypes showing comparatively susceptible (Pusa sawani, Dera local and Okra-3), 3 with intermediate (Karam-5, Sabz pari and Clean spineless) while 3 with resistant (Makhmali, Punjab selection and Green wonder) responses against jassid were selected for final screening trial during 2007. Differences were found to be significant among genotypes of okra during both the study years. The trend in selected genotypes towards susceptibility/resistance against jassid was similar to that observed during preliminary screening trial. Pusa sawani showed maximum Host Plant Susceptibility Indices (HPSI) i.e. 18 % and was susceptible, while Green wonder was comparatively resistant with minimum HPSI i.e., 5 %. Keywords: Okra, jassid, pest genotypes, Homoptera, susceptibility of jassid INTRODUCTION Okra is a summer and fall crop, widely cultivated from tropics to sub tropics (Kochhar, 1986). Okra, like other Malvaceae, is susceptible to a variety of pests that hinder its yield. Amrasca biguttula biguttula (Ishida) (Homoptera: Cicadellidae) is especially important in the tropics and subtropics because environmental conditions are often conducive year round for growth and development of host and pest. This pest is amongst the most important sucking insects that attack okra crop (Singh et al. 1993; Kakar and Dobra, 1988; Dhandapani et al., 2003) where it lays maximum number of eggs and thus becomes suitable place for survival and feeding (Hussain et al., 1979; Bernardo and Taylo, 1990; Sharma and Singh, 2002). The yearly increase in the cost of pesticides has gone out of the reach of common farmer. Therefore there is a need to develop alternates for handling such economically important pests approach. With the environmental friendly pest management approach, Host Plant Resistance (HPR) is one of the most cost-effective and safe methods. Plants contain a large number of substances, which have their primary use as a means of defense against natural enemies. A resistance variety can provide a base on which to construct an integrated control system (Maxwell et al. 1972, Gallun et al., 1975) and may be most fruitful when used in connection with other methods of control. HPR is seen to be a sustainable approach to pest management and varietals trials of different okra plants to jassid is essential. This was an attempt to identify the response by different available genotypes of okra to jassid in order to determine resistance/ susceptibility. MATERIALS AND METHODS Studies were carried out during 2006 and 2007 to screen okra genotypes based on per leaf population density count. Thirty genotypes of okra were sown in the experimental area of Post-graduate Agricultural Research Station, University of Agriculture, Faisalabad on March 31, 2006 (Table-1). Based on per leaf population density of jassid, three genotypes each showing resistant, susceptible and intermediate response for test insect were selected for further experiments. Nine genotypes of okra selected on per leaf population density-count-data from preliminary screening trial were sown on March 31, 2007. Experiments were laid out in a Randomized Complete Block Design (RCBD) with three replications. The row to row distance was kept at 75 cm and plant to plant was 30 cm. The plot size was maintained at 15 m × 20 m during the study seasons. No plant protection measure was applied and the material was screened under natural insect pressure. All the recommended agronomic practices were adopted during the experiment. Jassid population was recorded early in the morning twice in a week 24 days after sowing. For counts of jassid population, 15 plants of each genotype in each replication were selected at random and tagged. The leaves were observed in such a way that, one leaf at upper portion of the first plant, one leaf in middle portion from the second plant and one leaf from bottom portion of the third plant of each variety was taken in to account. The data were analyzed statistically using M- Stat package. The means were compared by LSD test at P = 0.05. 448