Effect of mycorrhizal fungi and phosphorus fertilization on fruit characteristics of three almond cultivars under rainfed conditions

The aim of this study was to investigate the effect of mycorrhiza and phosphorus fertilizer on fruit traits of three almond cultivars of ‘Shahrood 12’, ‘Tonu’ and ‘Supernova’ in a split-split plot experiment base on a randomized complete block design with 54 almond trees and three replications. This research was conducted in Eghlid city during 2016 growth season. Nutrient treatments were included three levels of diammonium phosphate (0, 250 and 500 g/tree) and two levels of mycorrhiza (0 and 500 g/tree). Maximum number of flowers was achieved by using mycorrhiza, in ‘Shahroud 12’ cultivars. The highest number of remained fruit (74), fruit width (1/6 cm) and length (3/7cm), weight of the 100 kernels (450g), leaf phosphorus (0/46%) and oil percent (47%) were observed in ‘Superunova’ by using 500 g diammonium phosphate and 500 g mycorrhiza. Mycorrhiza and phosphate fertilizer significantly enhanced vegetative growth traits such as leaf area, fruit length and width, fruit weight and kernel to skin ratio. The leaf phosphorus concentration and oil percentage of the kernel were increased significantly in response to both fertilization treatments. Based on the results of this research, ‘Superunova’ is considered as a superior cultivar and the most suitable fertilizer for a 10-year-old almond tree under rainfed condition was 500 g diammonium phosphate and 500 g mycorrhiza.