Effect of physico-morphic characters and environmental factors on infestation of thrips (Thrips tabaci) on five onion cultivars

Abstract

Resistance to plants is frequently associated with physical, morphological, physiological, biochemical, molecular and genetic characteristics of the plants. As very little information is available on the effects of physico-morphic characteristics and environmental factors on thrips (Thrips tabaci) infestation, therefore, in the present study such effects were evaluated on the infestation of thrips on five onion cultivars. Maximum number of adults and infestation of thrips was recorded on Marvi followed by Golden Orb while the adults and infestation was the minimum on Red Orb. Significant variations were observed in plant heights and girths among five onion varieties after 40, 70 and 100 days. Similarly, maximum yield was observed in case of Red Orb followed by F1 Mustang while the minimum yield was obtained with cultivar Marvi. The low temperature, high temperature and average temperature showed significant and positive correlations among all the cultivars. However, the average relative humidity showed negative and non-significant correlation for all the varieties. The correlation between physico-morphic characteristics and adult population was found significant for plant girth after 40 days while the correlations were non-significant for all the other factors. It is concluded from the present studies that Red Orb is comparatively resistant cultivar harboring the minimum thrips population. The highest yield was also recorded in case of Red Orb as compared to other tested cultivars and recommended for cultivation to enhance economic returns of farmers.