Variation in spring growth within white clover

Abstract

In a spaced plant trial, plants of 27 cultivars in their second year of growth were undefoliated from late winter through spring and their growth rate determined relative to that of 'Grasslands Huia'. Variation between cultivars was large. Cultivars which had higher relative growth rates than Huia during this period included some small-leaved frost tolerant germplasm, although all of these had lower absolute growth scores than Huia. The second study measured proportion of clover, leaf size and stolon growing point densities of 27 white clover cultivars and breeding lines grown in mixed species grazed swards during late winter and spring in two successive years. Once again, variation between cultivars in spring performance relative to Huia was large. It was concluded that there is sufficient variation available within white clover for improvements in spring growth relative to Huia to be achieved by breeding. Nematode Resistant Pitau consistently had high growth rates relative to Huia in late winter and early spring,but this did not carry through into late spring. Cultivars and lines with better late winter growth than Huia had higher stolon growing point densities for their respective leaf sizes than poorer, later winter growers. Keywords evaluation, mixed swards, spaced plants, later winter growth, stolon density