The effect of iba on rooting of vegetative cuttings taken from camellia sinensis (L.) o. kuntze plants of different ages

Camellia sinensis (L.) O. Kuntze, a member of the Theaceae family, is widely consumed as tea both globally and in Türkiye. The propagation of this economically important plant is crucial for the sustainability of tea cultivation. The use of scientifically developed tea seedlings in newly established or rejuvenated tea plantations enhances yield and quality, increases resistance to diseases, and supports sustainable agriculture. In this study, the effects of different Indole-3-Butyric Acid (IBA) concentrations on the rooting of vegetative cuttings taken from tea plants of different ages were investigated. The experimental area was divided into two slope groups, and cuttings were collected during three shoot periods (May, August, and October), treated with four IBA concentrations (0, 500, 1000, and 1500 ppm), and obtained from two types of mother plants (shrub and tree forms). Each treatment was replicated three times with 30 cuttings per replicate, and all cuttings were planted in 100% perlite medium. After 90 days, root length, number of roots, number of leaves, below-ground and above-ground biomass were measured, and the numbers of viable, callused, and rooted cuttings were recorded. According to the statistical analyses, the most effective IBA concentration was 1500 ppm for cuttings from shrub-form mother plants and 1000 ppm for cuttings from tree-form mother plants. When evaluating the effects of time and slope on rooting in shrub-form cuttings, it was found that root length and number of roots were higher in August and October cuttings on 20–30% slopes, whereas the highest below- and above-ground biomass values were observed in May cuttings on 30–50% slopes. Regarding the interaction between time and IBA concentration in shrub-form cuttings, the longest root length (6.74 cm) was observed with 1500 ppm IBA, and the highest root number (16.64) was recorded with 1000 ppm IBA. Root length peaked in August, root number in October, and both below- and above-ground biomass reached their highest average values in May. When all combinations of time, slope, and IBA concentration were considered for shrub-form cuttings, the highest survival rates were recorded in the following conditions: May shoots on 30–50% slopes treated with 500 or 1500 ppm IBA, and August shoots on 30–50% slopes with 1500 ppm IBA. For cuttings from tree-form mother plants, the highest survival rates were observed in October cuttings at all IBA levels. The highest rooting rate overall was achieved with August cuttings from shrub-form plants treated with 1000 ppm IBA.