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５０～６０年代，冀中南地区的稀植苹果幼树，由于生长旺盛，普遍存在着成花难、适龄不结果的问题，经试验采用多留、长放修剪技术后，取得了显著成效。１９７２年在此基础上对乔砧密植苹果进行了小冠自由半圆形（也称单层半圆形）试验，１９７８年乔砧密植金冠、青香蕉（...
From 1950s to the 1960s, the seedlings of sparsely-planted apple trees in central and southern part of Hebei Province were generally experiencing the problem of difficult flower formation and unsuitable age due to their vigorous growth. On this basis in 1972 on the Joe anvil close-planting apple small crown free semicircle (also known as single-layer semicircle) test, 1978 Joe ankle planting crown, green banana (...