Recurrent Selection for Improved Seed Germination, Seedling Elongation, and Seedling Emergence in Cicer Milkvetch1

Abstract

Relatively poor seedling vigor restricts the use of citer milkvetch(Astragalus cicer L.), a nonbloating forage legume. To capitalize on the genetic variability for early seedling vigor, one cycle of simple recurrent selection and one cycle of modified simple recurrent selection were conducted within the cv. Monarch for improved seed germination and seedling elongation at 5/20 °Ca nd1 2/20 °C temperature regims in the laboratory and for seedling emergence in the field. Seedling emergence was the primarcyr iterionf or selecting parentsf or the next cycle. Following one cycle of selection at 5/20 °C, 32, 37, and 26% of the progenies were significantly (5%)b etter than Monarch for seed germination, seedling length, and seedling emergence, respectively. Following one cycle of selection at 12/20° C, 12, 19, and 21% of the progenies were significantly better than Monarch for seed germination, seedling length, and seedling emergence,respectively. Selection for early ~eedling vigor under relatively cool eonditions in a controlled environment improved seedling emergence under field conditions. Although percentage seed germination and seedling length were significantly (5%) correlated in all populations, the correlation coefficients were of low predictive value (r = 0.25 to 0.63). Seedling emergence was not consistently correlated with percentage seed germination, seedling length, or seed weight. Consequentlys,e lected progenies must be evaluated under field environments to determine early seedling vigor.