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Plants cultivars possess different antixenotic and/or allelochemical properties, which resultantly induce in them different mechanisms of resistance. Variation in resource input (antixenotics and allelochemicals) to plants triggers bottom-up effects on ber-fruit fly interactions. However, variation in plant extrinsic and intrinsic traits in response to resource availability may modify the bottom-up effects. Cultivars Tikadi and Katha showed significantly low incidence (10.8 & 13.1 %, respectively) and Sanaur-5, Sanaur-4 and Sanaur-3 had significantly higher incidence (79.3, 81.5 & 82.0%, respectively). On the basis of pooled data of fruit fly incidence, Tikadi, Katha and Illaichi were found to be resistant; BS-75-1, Safeda, Dandan, Gola, Goma Kirti, Jogia, Narma, Mundia, Reshmi, Seb, ZG-3, Umran and Akharota were found to be moderately resistant; Banarasi Karaka, Banarasi Pawandi, Chhuhara, Kaithli, Thar Sevika and Thar Bhubraj were susceptible whereas Sanaur-3, Sanaur-4 and Sanaur-5 were highly susceptible. The resistant cultivars Tikadi, Katha and Illaichi was having pulp texture (hard) and fruit surface (ridge and plain) being high in resistant and low in susceptible cultivars. The pericarp thickness (-0.85) had significant negative correlations and pulp:stone ratio (0.47) and fruit length (0.42) had significant positive correlation with percentage fruit infestation. The maximum variation in fruit infestation was explained by fruit length (1.90%) followed by pulp: stone ratio (1.60%) and pericarp thickness (0.20%), whereas the remaining biophysical fruit traits explained < 1.0% variation in the fruit infestation. The flavonoids, tannins and phenols contents ranged from 40.7 to 179.0 mg/100 g, 264.8 to 511.6 mg/100 g and 113.1 to 239.0 mg/100 g (on dry weight basis), respectively with values significantly higher in resistant and lower in susceptible cultivars. The percentage of fruit infestation with flavonoid (-0.914), tannins (-0.914) and phenols (-0.947) had significant negative correlation. Backward stepwise regression analysis indicated that flavonoid and phenols contents explained 89.0% of the total variation in fruit fly infestation. The maximum variation in fruit infestation was explained by flavonoid content (83.5%) followed by phenols (5.5%), and tannin (1.9%). Based on the Kaiser Normalization method, two principal components (PCs) were extracted explaining the cumulative variation of 84.72% in fruit fly infestation. PC1 explained 59.85 % of the variation while PC2 explained 24.87 % of the variation. In conclusion, diversity of ber cultivar can improve plant fitness via bottom–up effects on fruit fly infestation. Growers can adopt potential cultivars of ber as identified for resistance (Tikadi, Katha and Illaichi cultivars) with minimal financial investment for obtaining higher yields. Hence, a benefit of diversity for yield potential is recognized and thus cultivars diversity is used to become an important answer for sustainable management. |
