2018 Volume 17 Issue 1 Pages 87-93
This study clarified suitable times for the single spraying of a fruit cluster with forchlorfenuron (1-(2-chloro-4-pyridyl)-3-phenylurea, CPPU) to reduce radial fruit cracking during tomato production under a rain shelter. We examined the relation between fruit development at the time of CPPU spraying and the occurrence of radial fruit cracking. The rate of occurrence was reduced in fruits that had been sprayed when they were 1.5–6.5 cm in diameter. The CPPU spraying time was regarded as the time when the maximum fruit diameter in the truss is 3.0–4.9 cm, with the minimum fruit diameter being about 1.5 cm. Actually, radial fruit cracking was clearly reduced by CPPU spraying at the time with a 3.0–4.9 cm maximum fruit diameter, although the reduction was somewhat unclear by spraying at the time of flowering or at the time with a maximum fruit diameter of 1.0–2.9, 5.0–6.9, or 6.0–7.9 cm. The reduction of radial fruit cracking by CPPU spraying was regarded as attributable to the increase in cell numbers near the fruit epidermis. The CPPU spraying did not significantly affect the harvested fruit number, average fruit weight, or total fruit yield. The marketable fruit yield increased along with the reduction of radial fruit cracking by CPPU spraying. The shape and quality of fruits sprayed with CPPU and untreated fruits were equivalent.
