Relationship between spring vigor and the presence of adventitious roots in established stands of red clover (Trifolium pratense L.)
Two experiments were undertaken to investigate the relationship between the presence of adventitious roots growing from the crown of red clover plants and the spring vigor of those plants. Experiment 1 was conducted in the springs of 1988 and 1989 in commercial stands of red clover-timothy mixtures entering their third year. Two hundred and thirty-seven plants were visually rated for spring vigor and degree of adventitious rooting using an ordinal scale. Experiment 2 was carried out on a research plot entering its fourth year and consisting of mixtures of red clover and timothy. Visual scores, taproot and adventitious root volumes and foliage weight were recorded. In all experiments significant differences (P < 0.01) in average spring vigor score were found among the five root classes. Correlation coefficients between spring vigor and adventitious root scores were 0.49, 0.65 and 0.58 for exp. 1 (springs of 1988 and 1989) and exp. 2, respectively. Adventitious root volume made up 86% of total root volume in exp. 2. Significant positive linear relationships were found between foliage weight and adventitious root and taproot volumes. It was concluded that profuse production of adventitious roots imparts better spring vigor to red clover. Key words: Taproot, adventitious root, red clover