Fruit physicochemical properties of several cultivars of date palm and their influence on the susceptibility to Oligonychus afrasiaticus (Acari: Tetranichydae) in the southern of Iran

Abstract

Sixteen date palm cultivars were studied for their susceptibility to the date palm dust mite, Oligonychus afrasiaticus, at Date Palm and Tropical Fruit Research Institute of Bushehr, Iran. Physicochemical attributes of these cultivars were also measured at Kimri stage. The results revealed significant differences among cultivars regarding susceptibility to O. afrasiaticus. The cultivars Haleli, Maktoub, Barahi, and Deglet Noor were more resistant to the date palm dust mite than the other cultivars. Significant differences were also observed among cultivars for physicochemical characteristics. Fruit length ranged from 2.18 to 4.15 cm, fruit mid diameter from 1.52 to 2.70 cm, fruit cap diameter from 0.82 to 1.10 cm, pericarp thickness from 1.51 to 6.12 mm, exocarp thickness from 0.24 to 0.54 mm, fruit weight from 4.21 to 17.24 g, kernel weight from 0.23 to 1.47 g, pericarp to kernel weight ratio from 4.45 to 16.67, strand weight from 26.33 to 184.75 g, bunch weight from 1.45 to 10.80 kg, number of strands from 26.33 to 91.33, fruit tissue firmness from 3.08 to 4.76 kg/cm 2 . The percentage of infestation to the mite had a significant positive correlation with the Kernel weight, fruit length, and number of strands. Tannin content ranged from 0.97 to 8.13%, TSS from 10.00 to 70.00% Brix, and titratable acidity from 0.70 to 1.50%. No significant correlation was observed between chemical characteristics of date fruits and infestation to the mite. Such information can be used to screen cultivars of date palm for date fruit processing industries and breeding programs.