RECURRENT SELECTION FOR EXTENDED PLANT HEIGHT AND HERBAGE YIELD IN CICER MILKVETCH

Cicer milkvetch (Astragalus cicer L.) produces about 50% of its total herbage in the first harvest and only about 12% in the third harvest u nder a three-harvest regime. The photoperiod-induced-dormancy response offers an opportunity to improve herbage yield during the third growt h period (1 August-10 September). Therefore, the objective of this stu dy was to improve herbage yield during the third growth period without sacrificing yield in the other two growth periods. This study was con ducted with spaced-plants under irrigation near Fort Collins, CO, from 1984 through 1990. Extended plant height (length of longest stem) rel ative to the cultivar Monarch was increased 105, 108, and 114% in the first, second, and third harvests, respectively, by two cycles of recu rrent selection. Mean plant herbage yield relative to Monarch was incr eased 113, 107, 116, and 111% for the first, second, and third harvest s and for total yield, respectively, by two cycles of recurrent select ion. Although herbage yield was increased substantially in the third h arvest, simultaneous increases in the first and second harvests result ed in no difference for seasonal distribution of total yield. The 15 c lones with the best performing polycross progenies for extended plant height and herbage yield were used as parents for the cultivar Windsor . Recurrent selection for lack of the photoperiod-induced-dormancy tra it was an effective procedure for improving extended plant height and herbage yield of cicer milkvetch during the third growth period of a t hree-harvest system.