Root growth of white clover ( Trifolium repens l.) lines in glass–fronted containers

The root system development of five white clover lines was followed for 3 years in glass‐fronted containers 1.3 m deep. Root tips were counted each month. ‘Grasslands Huia’ and ‘Ladino’ produced root tips most rapidly in the seedling year until the end of spring. ‘Ladino’ consistently had the highest number of root tips visible in the second and third years. All lines followed the same seasonal trends and produced most root tips in spring. Percentage of root tips at each 15 cm depth down the profile decreased at a similar rate for all lines. For the first 6 months ‘Ladino’ had much shorter roots per root tip than the other lines. Huia had the highest mean number of vertically penetrating roots (counted each February and August) followed by ‘Sweden’, ‘Ladino’, ‘Kent’, and ‘Godley Peaks’. At the completion of the study root systems were removed and dry weighed. At all depths ‘Ladino’ had the highest root dry weight, followed by Huia, ‘Sweden’, ‘Kent’ and ‘Godley Peaks’. ‘Kent’ and ‘Godley Peaks’, however, had a significantly lower percentage of dry weight in the bottom 45 cm. An unreplicated, general comparison was made with Lotus pedunculatus Cav. cv. Grasslands Maku. It was concluded that glass‐fronted containers were a valuable and informative technique for distinguishing differences among white clovers.