Plant Regeneration from Cotyledon Nodes of Chieh-qua (Benincasa hispida Cogn. var. Chieh-qua How) in Vitro

In order to establish and optimize regeneration system in vitro, cotyledon nodes of Chieh-qua (Benincasa hispida Cogn. var. Chieh-qua How) was used as explants in this study. The effects of seeds sterilization methods, plant growth regulators (PGRs) combinations and genotypes on callus induction, shoot regeneration and rooting were studied. The results showed that the optimal sterilization method for seeds of chieh-qua was to treat the peeled seeds with 75% alcohol for 20 s, and then with 10% sodium hypochlorite (NaClO) for 8∼10min. The optimal medium of adventitious buds induction was MS medium supplemented with 6-benzylamino purine (6-BA)0.5mg·L-1 and abscisic acid (ABA) 1 mg·L-1. The highest induction rate of adventitious buds (76.17%) was obtained from line A39FA, which was considered as the best genotype among the six genotypes used in this study. The half-strength MS (1/2MS) medium supplemented with indole-3-acetic acid (IAA) 0.5 mg·L-1 was suitable for inducing rooting with vigorous roots and strengthening the vigor of plantlets. The system established in this study provided a basis for the genetic transformation of chieh-qua.