Breeding Cicer Milkvetch for Improved Seedling Emergence1

Abstract

Cicer milkvetch (Astragalus cicer L.) has not been grown extensively because of its relatively poor seedling emergence. Therefore, selection for rapid seedling growth at two temperature treatments in environmental chambers and selection for rapid seedling emergence in the greenhouse were evaluated as methods for improving seedling emergence under field conditions. In the environmental chambers with a 15‐hour photoperiod, one cycle of recurrent selection was more effective at the 20 C day/15 C night than at the 25 C day/20 C night regime. Percentages of progeny in which seedling emergence was significantly higher than that of the reference were 44 and 15 for the 20/15C and 25/20C regimes, respectively. Because of concern for inbreeding depression, intercross progenies were evaluated for seedling emergence prior to the second cycle of recurrent selection. Of the intercross progenies selected, seedling emergence was significantly improved in 53% from the 20/15 C and in 17% from the 25/20 C regime.Selection for rapid seedling emergence from a 3.8‐cm depth of planting hi the greenhouse was not an effective method for improving seedling emergence in the field. Only 8% of the selected polycross progenies were significantly better than the reference progeny. Seedling emergence was poor in polycross progenies of other populations not selected for rapid seedling growth at 20/15 C. Only about 2% of such progenies were significantly better than the reference progeny. Selection of seedlings for rapid growth in a 20/15 C environment was an effective method of improving seedling emergence of cicer milkvetch under field conditions