Investigation of callus induction in Chardonnay grapevine (Vitis vinifera L.)

Callus induction is an important step in plant transformation aimed at improving grapevines, one of the most cultivated fruit crops. Callus induction can be influenced by nutrients, plant growth regulators, physical environments, explant type, infection, and genetic factors. This study investigates the efficiency of callus induction in the Chardonnay grape variety using different nutrient mediums, plant growth regulators, and explant types. Internode and leaf disc parts were selected as explant types and cultured in Murashige and Skoog (MS) and Lloyd and McCown Woody Plant (WP) nutrient medium with 7% agar, containing varying concentrations of plant growth regulators such as NAA, 2,4-D, and BA. Different combinations resulted in various types calli, including friable, compact, shooty, and rooty, with different colors by the end of the 21st day. WP medium consistently yielded the highest callus induction rates across all plant growth regulator combinations. The combination of 0.5 mg/L 2,4-D and 0.2 mg/L NAA in MS medium produced the largest callus area in internode explants. Conversely, leaf discs exhibited lower callus induction rates. Additionally, 1 mg/L BA and 0.2 mg/L NAA in MS medium promoted shoot formation, while the same combination in WP medium facilitated both shoot and root formation in internode explants.