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 the Date Palm and Tropical Fruit Research Institute of Bushehr, Iran. Three date palms naturally infested by O. afrasiaticus were randomly selected per cultivar. Four fruit strands per bunch of each sampling tree were randomly collected, and the number of healthy and infested fruits was counted. Fruit physicochemical attributes of these cultivars were also recorded at the Kimri stage using standard procedures. The analysis was carried out according to a completely randomized design. The results revealed significant differences among cultivars regarding susceptibility to O. afrasiaticus. The cultivars Barahi, Maktoub, Haleli, and Deglet Noor, were more resistant to the date palm dust mite than the other cultivars. Significant differences among cultivars were also observed in all tested physicochemical characteristics. The percentage of infestation had a significant positive correlation with the Kernel weight, fruit length, and the number of strands. Tannin content ranged from 0.97 to 8.13%, total soluble solids (TSS) from 10.00 to 70.00% Brix, and titratable acidity from 0.70 to 1.50%. No significant correlation was observed between the chemical characteristics of date fruits and infestation to the mite. Such information can be used to screen date palm cultivars for date fruit processing industries and breeding programs.

Keywords

• cultivars
• date palm dust mite
• host plant resistance
• phoenix dactylifera