ISHS Acta Horticulturae 199: II International Workshop on Temperate Zone Fruits in the Tropics and Subtropics
APPLES AND PEACHES IN TROPICAL HIGHLANDS OF THE PHILIPPINES |
| Authors: | F.G. Hermano, J.F. Ben-ek, T.T. Vargas, G.R. Edwards |
| Abstract:
Six low-chill apple cultivars, imported from Northern Hemisphere were planted in the dry season, February 1984 at Baguio, elevation 1500 m, latitude 16°25". Three to five long shoots grew vigorously from the maiden stem. After 5 months, while still growing strongly these were topped, defoliated and tied horizontally. Lateral buds burst and formed spurs with terminal buds. These were defoliated again after 5 months. Some flowers emerged and a few fuit set. Anna and Dorset Golden responded well to defoliation. Beverly Hills and Gordon burst poorly. Gordon produced long shoots rather than spurs. The Indonesian practice of bi-annual defoliation and tying down of long shoots is being continued successfully. Timing of treatments in relation to leaf maturity is critical. For chemical defoliation, 4–6% CuSO4 was most promising. For breaking bud dormancy, 2% Thiourea was effective. For growth restriction, Alar 1 000 and 2 000 ppm were effective. A selection of peach and nectarine cultivars from Northern Hemisphere was planted in the dry season, February, and from the Southern Hemisphere in the wet season, July, 1984. Initial vegetative growth was very vigorous but most cultivars stopped naturally within 5–6 months of planting. Flower bud formation was profuse. PP333 soil drench or foliar spray hastened growth cessation in cultivars which did not stop naturally. A new growth cycle was induced by defoliation. Hand defoliation is tedious. Chemical defoliation with CuSO4, ZnSO4, Ethephon and Mg(C103)2 was tested. Mg(ClO3)2 as 'Mag 40' at 0.38% a.i. was most effective provided foliage was mature. Poor bud burst followed hand defoliation. Of the dormancy breaking treatments compared, KNO3 4% induced flower bud opening; Thiourea 2% induced leaf bud opening; H2CN2 and DNOC-winter oil induced both leaf and flower buds. The best treatment was 8% of DNOC-oil concentrate containing 2.2% DNOC and 10% oil applied one month after defoliation. Fruit set of chemically induced flowers occurred in the dry season planting. Mature fruit of promising quality was harvested in 12 months from planting. In contrast, fruit set was prevented by heavy rain in the wet season planting. Vegetative growth was poor in the second growth cycle of the dry season planting. Poor soil drainage is suspected. The second growth cycle was better in the later planted trees on better drained soil. Ratooning to induce new trees from basal buds was effective provided the root environment is favorable. | |
