Light spectrum and indolebutyric acid (IBA) in rhizogenesis in herbaceous cuttings of guava trees

Background: In the production of seedlings, success in the market is due to a quality product. Well-developed seedlings with a good root system, appear as a key factor to guarantee suitable products. Light can be used as a stimulating factor for rooting, in adequate light quality. Photoselective screens can be used to make rooting more efficient. Methods: To evaluate this factor, herbaceous cuttings of Guava Tree “Paluma” were used, exposed to different wavelengths in mini-greenhouses covered with cellophane of the colors: green, yellow, red, blue, transparent and orange, and subjected to five treatments with Indolebutyric Acid (IBA) (0, 1000, 2000, 3000 and 4000 mg.kg-1), grown in a 3: 2: 1 substrate (sand: earth: bioplant®), in a randomized block design, with a 6x5 factorial and four replications with 10 cuttings in each treatment. Ninety days after staking, the following variables were evaluated: cuttings survival, number of leaves; number of sprouts; largest sprout length; root length; root volume; green mass of leaves and root; dry mass of sprout and root. Results: The orange and red light spectra were superior in rooting the guava cuttings, and may be an option in covering the seedling production nurseries of this fruit tree. Conclusion: The use of IBA neutralized the luminous influence of the light spectra with non-significant results for the interaction.