Effects of different growth regulator treatments and culture mediums on clonal propagation of alfalfa

Alfalfa (Medicago sativa) is a typical perennial autotetraploid and outcrossing plant. The sexual reproduction of alfalfa is susceptible various factors, and its original genetic integrity is easy to lose. Vegetative propagation of alfalfa by stem cutting is extremly important to ensure the genetic stability of alfalfa resources and cultivars. In this research, taking male sterile mutant (ms1) identified in alfalfa as experimental material, the effects of different growth regulator treatments and culture mediums on its clonal propagation were studied. The results showed that, there were significant differences among treatments of three growth regulators on the clonal propagation (P0.05). The efficiency of ABT was the best for the regeneration, and then followed by NAA and IBA. The highest rooting rate reached under treatment of 150 mgL-1 ABT. Under this treatment, the survival rate was up to 88.3%, which was 71.0% higher than that of the control (P0.05), and also exhibited the good performance of numbers of root (3.94), root length (8.96 cm), rooting effect(0.74) and numbers of leaf (10.46). The survival rate of all the cuttings was not significant different among the five culture mediums (P0.05), while significant differences in the numbers of root, root length, rooting effect and numbers of leaf were found (P0.05). The mixed culture medium was better than the single culture medium, which provided a good support for the growth of cloning plants, and the efficiency of M4 (soil + vermiculite + perlite) and M5 (soil + sand + perlite) were the best compared to the single garden soil.