Fruit analysis as a new approach to evaluate boron status in avocado

Abstract

A tissue analysis trial for the diagnosis of boron status was performed during the 2003 growing season in Paine County, Metropolitan Region, Chile. Five-year-old 'Hass' avocado (Persea americana Mill.) trees were soil treated with borax [11% boron (B)] applied to the soil surface at rates of 0, 75, 150, or 300 g/tree, each with three replicates. Borax was incorporated into the soil approximately two and half months after flower anthesis, applying half of the dose on each side of the tree along the closest irrigation furrow. Thirty spring flush leaves and 15 fruits with peduncle were collected per tree 4 months after application. Boron concentration in leaf, fruit peduncle, and fruit pulp was determined by spectrocolorimetry. Differences among treatments were better detected in peduncle and pulp samples than in leaf samples. The relationships between borax dose and B concentration in the tissue were R-2 = 0.77,0.75, and 0.53 in peduncle, pulp, and leaf, respectively. Consequently, peduncle and pulp appear as promising tissues, probably better than leaf, for diagnosing the boron status of avocado trees.