Growth potential of buds of two contrasting cultivars of white clover during winter and early spring

In order to compare the growth potential of buds of two contrasting cultiva rs of white clover (Trifolium repens L.) (cv. AberHerald and Grasslands Hui a) during the winter-early spring period, we adapted a method to assess the potential for activity of shoot buds and root primordia. The growth potent ial was evaluated following the excision of individual stolen nodes sampled in the field, from experimental plots located in the eastern part of Franc e. Two populations of nodes were sampled: (i) the youngest node emerged fro m the apical bud (node i), (ii) the third node behind the apex (node 3). Th e excised nodes were placed in controlled conditions and the outgrowth of a xillary buds and roots was recorded every day for a week. The study demonst rated a seasonal influence on the potential for activity of axillary buds a nd root primordia, particularly for buds at node 3. The proportion of poten tially active shoot and root buds was less than 50 % at the end of March, a nd then increased from end of March to reach 80 % in April. The data indica ted a genetic variation in potential for outgrowth during winter. AberHeral d had a higher percentage of potentially active buds than Huia during winte r, irrespective of the node position. Moreover AberHerald buds had faster r ates of outgrowth than Huia buds. Differences between cultivars in winter s urvival and potential for growth in spring were linked to identified cultiv ars' differences in developmental characteristics of buds.