SELECTION FOR AND HERITABILITY OF STOLON CHARACTERISTICS IN 2 CULTIVARS OF WHITE CLOVER

White clover (Trifolium repens L.) herbage production in intensively g razed pasture is related to clover stolen growing point density. High stolen density is associated with small leaf size. The objective of th is study was to examine the probability of breaking the genetically co ntrolled link between leaf size and stolen density by manipulating int ernode length and branching propensity. Two white clover cultivars, Gr asslands Tahora and Grasslands Kopu, were grown in two New Zealand env ironments, full sunlight or 50% sunlight (shade), during 1991 and 1992 . Selections were made for high or low frequency of stolen branching, long or short stolen internodes, and large or small leaves. These sele ctions were polycrossed within groups to give 24 lines. Lines were eva luated in pots grown outside to determine the effect of selection on t hese and other shoot characters. Selection of populations with high or low frequency of branching gave progeny with different frequency of b ranching for all cultivar-environment combinations except for selectio n within Tahora grown in shade. Selection of populations with long or short internode length gave progeny with different internode length in all cultivar-environment combinations. Selection for large and small leaflet width gave progeny with different leaflet width in all cultiva r-environment combinations except for selection within Kopu grown in s un. Two estimates were made of narrow sense heritabilities. Estimates from mid-parent versus progeny regression heritabilities were higher f or internode length and leaflet width than for frequency of branching. Realized heritabilities were again generally higher for internode len gth and leaflet width than for frequency of branching although there w ere some exceptions. Selection for high frequency of branching in Taho ra grown in full sunlight had a high realized heritability. Stolen cha racters, such as internode length and frequency of branching, can be e ffectively manipulated by selection. The degree of selection success c an be affected by environment and cultivar. Selection for variation in internode length is likely to be more successful than for frequency o f branching.