对英国草地研究所的田间试验小区的六个白三叶草的品种,于1977年10月27日全部进行一次修整性采摘,使所有的植株都没有残留的叶片。1978年春,将每一个小区分为南北两半,5月9日先采摘北面的一半,6月15日再采摘南面的一半。7月12和13日从每个小区的每一半草丛中采集30个茎的样品,样品尽可能采自不同的植株。每一个茎的样品,在放大到 Six white clover varieties of the field trial plot of the British Institute of Grasslands were all pruned on October 27, 1977, so that all the plants had no remaining leaves. In the spring of 1978, each district was divided into two parts, north and south. On May 9, it picked half of the north and half of the south on June 15. A sample of 30 stems was taken from each half of the grass in each plot on July 12 and 13, with samples taken from different plants wherever possible. Samples of each stem, enlarged to