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菠萝是一种密植的多年生作物,尤其近年来,种得更密。在夏威夷,每英亩种植16,000—18,000株(每亩2,667—3,000株),澳大利亚14,500—15,000株(每亩2,417—2,500株),中国台湾省18,000株(每亩3,000株)。在西马来西亚(即马来亚),有些小农每英亩种植17,000株(每亩2,833株)左右,有些大菠萝园则高达30,000株(每亩5,000株)。鉴于大面积栽培需要大量种植材料,而一株菠萝在18个月的生育期中只能产生约10棵种苗,育种者必须尽快增殖他所选育的优良无性系。
Pineapples are perennial crops that are densely populated, especially in recent years. In Hawaii, 16,000-18,000 plants (2,667-3,000 plants per acre) are planted per acre, 14,500-15,000 plants (2,417-2,500 plants per acre) in Australia and 18,000 plants (3,000 plants per acre) in Taiwan Province of China. In Western Malaysia (ie, Malaya), some smallholder farmers planted 17,000 acres (2,833 acres per acre) or as many as 30,000 (5,000 acres per acre) in some large pineapple fields. Since large-scale cultivation requires large amounts of planting material, and a pineapple can produce only about 10 seedlings during the 18-month growth period, the breeder must multiply the fine clones he has selected.