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 under a three‐harvest regime. The photoperiod‐induced‐dormancy response offers an opportunity to improve herbage yield during the third growth period (1 August–10 September). Therefore, the objective of this study was to improve herbage yield during the third growth period without sacrificing yield in the other two growth periods. This study was conducted with spaced‐plants under irrigation near Fort Collins, CO, from 1984 through 1990. Extended plant height (length of longest stem) relative to the cultivar Monarch was increased 105, 108, and 114% in the first, second, and third harvests, respectively, by two cycles of recurrent selection. Mean plant herbage yield relative to Monarch was increased 113, 107, 116, and 111% for the first, second, and third harvests and for total yield, respectively, by two cycles of recurrent selection. Although herbage yield was increased substantially in the third harvest, simultaneous increases in the first and second harvests resulted in no difference for seasonal distribution of total yield. The 15 clones 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 trait was an effective procedure for improving extended plant height and herbage yield of cicer milkvetch during the third growth period of a three‐harvest system.