The influence of 2, 4, 5-TP on the coloration, maturity and growth of apples and stone fruits

Abstract

A study was made as to the effect of 2, 4, 5-TP (2, 4, 5-trichlorophenoxypropionic acid) on the coloration, maturity and growth of apples and stone fruits (peach, plum, Japanese apricot, apricot and cherry), The present experiments were carried out at two localities (Sapporo and Yoichi) from 1955 to 1958.
The. results obtained are as follows:
Apple.
1. By spray applications of 2, 4, 5-TP, the colora-tion and maturity of the fruits are hastened re-markably. It is obvious especially in summer apples. They can be harvested 10 days to two weeks earlier than untreated fruits.
2. In most cases sugar content of the fruits is also increased.
3. Apples are not enlarged by the spray applica-tions of 2, 4, 5-TP.
4. As a result of storage tests, it was ascertain-ed, that the keeping quality of fruits is not at all affected by applications of 2, 4, 5-TP.
5. It was confirmed that applications of the che-mical about one month before usual harvest time with concentration of 20 ppm are most suitable for all apple varieties, excepting McIntosh, for which 40 ppm is recommendable.
Stone fruits.
1. Distinct enlargement of fruits was induced in all stone fruits. In such cases the growth of pits kept pace with that of the fruits, which is a fact that has never been reported hitherto.
2. Noteworthy acceleration of maturity of the fruits resulted in all stone fruits. As a result of it, intense red coloration occurred in plums and cher-ries.
3. Sugar contents of the treated fruits became higher than that of the untreated fruits.
4. Concentration of 40ppm was proved to be suit-able for most of the stone fruits, with the exception of peaches, for which 20ppm is recommendable. Malformation of fruits, in peach, is likely to result when 40ppm is applied.