Fig. 4. Fresh root and shoot weights of perennial ryegrass cultivars grown in flexible root tubes under greenhouse conditions. (A) Standard cultivars. (B) APR120 base population vs. cycles of selection for deep root production. (C) Bastion base population vs. cycles of selection for deep root production. Different letters indicate a significant difference at P 0.05 using Fisher's protected least significant difference mean separation. Connecting lines indicate the selection cycles over which the total percentage gain in each panel was calculated.