Exploring zinc impact on rooting efficiency in guava (Psidium guajava) cuttings under shade net environment

In pursuing efficient guava (Psidium guajava) cultivation, clonal propagation stands out for maintaining fruit quality and genetic uniformity. However, traditional methods like air layering could be more practical for mass production. The present study aimed to address the challenge of enhancing the rooting ability of guava stem cuttings without relying on labour-intensive auxin treatments under shade net environments in North Indian conditions. The study explores the natural augmentation of auxin levels through zinc application, considering zinc's pivotal role in auxin synthesis. The experiment involved foliar and basal zinc application on stem cuttings, evaluating various zinc sulphate concentrations. Notably, basal application of 75g zinc sulphate/tree significantly improved rooting and survival percentages, increasing by 52.13% and 79.92%, respectively. Root initiation was expedited to 22.25 days. Additionally, treated samples exhibited a 7.66 cm increase in average root length and a 1.52 g increase in root fresh weight compared to the control. Intriguingly, the most favourable results occurred when untreated stem cuttings were subsequently treated with IBA (Indole-3-butyric acid) at 5000 ppm. These findings highlight the potential of zinc application for naturally enhancing auxin levels, providing valuable insights for optimizing guava propagation efficiency. Moreover, zinc was reported to enhance the efficiency of auxin transport within plants. Specialized carrier proteins mediate auxin transport, and zinc was shown to influence the expression and activity of these transport proteins. Zinc can distribute auxin throughout the plant by promoting auxin transport from source to sink tissues, enhancing root growth and overall development.