Guava (Psidium guajava) crop is economically important in many countries with tropical and subtropical
climates. Internationally, Mexico ranks fourth in importance, following India, Pakistan, and Sudan. This
crop is highly valued for its nutritional properties, as it contains various functional compounds with
antioxidant activity. Guava propagation can be carried out by seeds (sexual reproduction) or through
asexual or vegetative methods. The former results in high variability in the progeny, whereas vegetative
propagation preserves the characteristics of the mother plant; consequently, the latter method is the most
widely used. Although various methods of asexual propagation exist, air layering is the most commonly
used in the study region. However, there is no information regarding the best type of substrate and/or
on the application of phytohormones that promote greater root development. The objective of the study
was to evaluate the effect of different substrates (coconut husk, peat moss, and rock wool) combined with
the application of three concentrations (0%, 50%, and 100%) of indole-3-butyric acid (IBA; RADIX
10000®) on the propagation of guava by air layering. The air layers were carried out on a productive
guava 15-year-old plant, typical of the region, located at the INIFAP "Los Cañones" Experimental Site
in Huanusco, Zacatecas, Mexico. Fifty-one days after the layering process, the layers were separated
from the mother plant, and the number and length of roots were recorded. The data were analyzed
using a factorial experimental design (3 x 3), with 10 replications and one layer as the experimental
unit. The results showed that substrates had a differential effect on root number and length: the highest
number of roots was observed with coconut husk, while the greatest root length was obtained with
peat moss, in both cases, at the 100% IBA concentration. Number and length of roots increased as the
IBA concentration increased, as compared to the control that showed the lowest values. Based on the
overall effects, it can be suggested that coconut husk is a suitable substrate for propagating guava via
air layering, besides it is less expensive than the other two substrates. According to the results, the use
of coconut husk with IBA (10,000 ppm) at 100% concentration is recommended for greater efficiency in
the rooting of air layers.
