Evaluation of antixenotic and allelochemical traits of ber (Ziziphus mauritiana Lamk.) fruits as source of host plant resistance against fruit fly (Carpomyia vesuviana Costa) (Diptera: Tephritidae) in semi-arid region of India

Abstract

The ber fruit fly, Carpomyia vesuviana Costa (Tephritidae: Diptera) is a well established notorious monophagous major pest of ber (Ziziphus mauritiana Lamk) in all the ber growing arid and semi-arid regions and may cause severe yield losses. Plants frequently display genetic variation within and between populations for traits that influence the host selection preference of herbivores. While analyzing the effect of various physico-chemical traits on the C. vesuviana infestation, significant differences in fruit fly incidence were observed in 39 cultivars of ber under field conditions. Fruit fly infestation had significant positive correlation with fruit size, average fruit weight, pulp: stone ratio, total soluble solids and Vitamin C, and was negatively correlated with fruit firmness, acidity content and total phenolic content. The maximum variation in fruit infestation was explained by total phenols (57.0%) followed by pulp: stone ratio (10.4%) and TSS (2.3%). Based on the varimax rotation method with Kaiser Normalization, two principal components (PCs) were extracted explaining the cumulative variance of 54.00% in fruit fly infestation. PC1 explained 29.91% while PC2 explained 24.09% of the total variance. Thus, the importance of genetic diversity is apparent and can be utilized to enhance the income of the farmers by reducing cost of cultivation by developing resistant cultivars which are major component of integrated pest management strategies.