ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Spring vegetative flush removal: the effect on yield, size, fruit mineral composition and quality.

Cutting, J. G. M. and Bower, J. P.

Yearbook - South African Avocado Growers' Association Year: 1990 Vol: 13 Pages: 33-34 Ref: 8 ref.

1990

บทคัดย่อ

A shoot pruning study was carried out in 4-year-old trees of cv. Hass. The vegetative flush which emerged from the centre of the flower panicle was removed either once at 50% flowering or weekly for 6 weeks from 50% flowering. A paclobutrazol stem injection treatment [rate not stated] without flush removal was also compared with the untreated control. Data are presented on fruit set, fruit starch content, yield, average fruit weight, number of fruits/tree, fruit mineral composition (P, K, Ca, Mg and Ca + Mg:K) as % dry mass and g/100 g dry mass, soluble PPO (polyphenol oxidase [catechol oxidase] activity) at full softness (eating ripeness) and the relationship between fruit mineral content and PPO. Vegetative flush removal resulted in increased initial fruit set as well as an increase in the late Jan. fruit drop. Final yields (in kg) were very similar for the 3 treatments and control. Fruits from trees that had been pruned for 6 weeks were 13% larger than control fruits. The different treatments had no effect on non-structural starch content. Pruning increased fruit concentrations of P, K, Ca and Mg. When expressed on a mass/fruit basis, the treatments that reduced vegetative vigour most severely showed the greatest mineral accumulation. High Mg levels and a high Ca + Mg:K ratio appeared to be positively related to a high PPO activity. The use of paclobutrazol markedly increased the potential for poor physiological postharvest quality (as determined using PPO activity). Pruning treatments did not reduce quality despite the increase in fruit size and, unlike paclobutrazol, did not greatly alter the mineral ratios.