Antixenotic and allelochemical resistance traits of ber (Ziziphus mauritiana) against stone weevil, Aubeus himalayanus in hot arid region of India

Plants cultivars possess different antixenotic and allelochemical properties, which resultantly induce in them different mechanisms of resistance. Variation in resource input (antixenotics and allelochemicals) to plants triggers for ber stone weevil resistance. The cultivars Kali, Katha, Illaichi and Tikadi were found to be resistant; Akharota, Dandan, Gola, Goma Kirti, Sanur-1, Seb, Umran and ZG-3 moderately resistant; Badami, Banarasi Karaka, Gularvasi, Jogia, Kaithli, Mundia, Reshmi, Sanur-3, Thar Bhubhraj, Thar Sevika and Thornless susceptible and Banarasi Pawandi, Chhuhara, Sanur-2, Sanur-4 and Sanur-5 highly susceptible cultivars against stone weevil. The fruit infestation ranged from 8.80 to 49.44 % on retained fruits and 13.31 to 73.77% on drooped fruits. Tannins, phenols, total alkaloid and flavonoid contents ranged from 123.61 to 222.06 mg/100g, 42.95 to 90.33 mg/100g, 0.52 to 1.48 % and 9.32 to 24.42 mg/100g, respectively with values significantly higher in resistant cultivars and lower in susceptible cultivars. Tannins, phenols, alkaloids and flavonoid contents had significant negative correlations (P = 0.01) with the percentage fruit infestation on plant fruits and the fallen fruits. The pulp: stone ratio ranged from 2.12 to 27.13 and was significantly high in susceptible and low in resistance cultivars. The highest pulp: stone ratio was found in variety Mundia and least in variety Tikadi. Most of the resistant varieties were having extremely hardy stones and in susceptible varieties the stones were slightly hard. The pulp: stone ratio was having significant positive correlations (P = 0.01) with percent fruit infestation on retained and the dropped fruits.