美国甜菜播种面积近九百三十五万亩, 全部用自产种子。美国甜菜制种的一些新动向是: (一)以秋播采种法取代母根栽植采种法。美国利用俄勒冈、亚利桑那和犹他三个州适宜的气侯条件,进行秋播采种,获得成功,取代了母根栽植采种法,可显著提高种子产量。一九七○年,美国甜菜种子平均亩 US beet sown area of ​​nearly 9350000 acres, all with self-produced seeds. Some new trends in seed production in the United States are: (a) the method of autumn seed planting instead of mother planting method. Using the favorable climatic conditions in the three states of Oregon, Arizona and Utah, the United States succeeded in planting trees in autumn and succeeded in replacing the method of planting seedlings by maternal roots to significantly increase the yield of seeds. In 1970, average sugar beet seeds of the United States