Exogenous auxin affecting rooting and establishment of air-layers for mass propagation of seedless lemon (Citrus limon)

Lemon is a higher consumer preferable and nutritious fruit crop whose propagation with air-layering is effective and commercially profitable, particularly for a seedless cultivar for which other methods proved were unfeasible. Therefore, an investigation was conducted during 2018–19 at Horticulture Department, College of Agriculture, RVSKVV, Gwalior, Madhya Pradesh, India to check out the influence of the utilization of exogenous auxins on root formation, proliferation, survival, and the establishment of lemon air-layers. Nine treatments replicated three times constituted of two phytohormones namely Indole-3-butyric acid and Naphthalene acetic acid each with the same four levels of concentrations, i.e., 1250, 2500, 3750 and 5000 mg/L separately beside control employed on 7 years old plants of seedless lemon under Randomized Block Design. The results were significant and disclosed that among rooting aspects viz. the minimum days required for callus formation and root initiation, maximum rooting percent and adventitious roots' fresh weight per air-layer, and growth aspects viz. the maximum survivability of air-layer, maximum mean shoots' length, the maximum mean number of branches & leaves after transplanting of air-layers were noted with the application of indole-3-butyric acid @ 5000 mg/L among all treatments. Indole-3-butyric acid performed better then naphthalene acetic acid, however both auxins gave promising results at 5000 mg/L concentration.