Critical factors governing the efficient direct organogenesis in green-fleshed kiwifruit (Actinidia deliciosa) [A. Chev.] var. deliciosa

The present study was focused towards determining the factors governing direct organogenesis in kiwifruit cultivar 'Allison'. Using in vivo buds or nodal segments as explants, the maximum 75.5% uncontaminated explants were obtained upon consecutive individual disinfection treatment with 1% carbendazim (3 min), 0.1% HgCl2 (1 min), and 2% NaOCl (2 min), respectively. The maximum shoot regeneration response of 84.81% was recorded on Murashige and Skoog (MS) medium fortified with 0.45 mu M BA, 0.1 mu M IBA, and 0.13 mu M GA(3). The months of May displayed the highest in vitro explant regeneration response for two consecutive years. The highest shoot proliferation rate was 1:6 with a 5.34 mean number of shoots and a maximum mean shoot length of 6.32 cm on MS medium containing 0.22 mu M BA, 0.1 mu M IBA, and0.69 mu M GA(3). A two-step or sequential approach for in vitro root induction showed good quality rooting response of 91.03% producing a higher number of long (2.23 cm) roots per shoot, and afterwards, the plantlets were hardened successfully with a higher survival rate (95%). Also, ISSR markers confirmed the genetic fidelity of the in vitro-raised regenerants.