Guava is propagated both by seeds and vegetatively.  But vegetative propagation is followed commercially.

Seed propagation: Despite the large number of seeds that can be obtained from the fruit, guavas are not usually propagated from seeds. Seeds often germinate in 2-3 weeks. The main reason for this is that guava seedlings do not retain the characteristics of the parents and they bear fruits of variable sizes and quantity though they have long life span. However, seeds are used for seedlings production for breeding and selection programmes or just rootstocks for grafting of desirable cultivars.The propagation of guava through seeds should not be encouraged because the seedlings have long juvenile phase, give lower yields and bear poor quality fruits. But the seedlings serve as rootstock material for grafting or budding.

For planting seedlings, seeds should be collected from the plants producing high quality fruits and high yield. Fully matured seeds of the current season are used for sowing. There is no evidence to indicate that seed source for the production of rootstocks is important. The seeds should be sown as soon as possible after extraction from the ripe fruits. Soaking of seeds in water for 12 hours or in hydrochloric acid for 3 minutes gives about 90% germination. Seeds are sown in well-drained growing medium where more than 90% of seeds will germinate within 15-20 days. Improvement in rate of seed germination through plastic mulching has been achieved for guava.

The seedling trees rose in the nursery or polyethylene bags can be transplanted in the fields when they are 6-8 weeks old.

Vegetative propagation: Grafting has been shown in other tree species to provide precocity, desirable dwarfness and economy for picking and pruning. Vegetative propagation is widely practised to ensure that the plants are true-to-type and early bearing, although it is not easy to graft guava. Guava trees for eventual field planting can be nursery propagated by grafting, budding, stem cuttings using succulent green stems, or root cuttings. Seedlings for grafting or budding can be propagated using guava seeds from the wild or from clonal trees. About 1 year old, seedlings are ready for grafting or budding. Healthy, succulent, and highly vegetative seedlings thus propagated can be grafted or budded when they are about 12-20 mm in diameter at 25 cm above ground level. Budding is preferred over other grafting techniques, because bud growth is faster and each bud on a scion or bud wood is a potential plant. The patch-bud technique gives good results. Patch-budding has been successful in California when large stock-plants have been used. They should have stems 2.5 cm diameter, and the buds should be cut 4 cm in length, square or oblong in form.

For grafting, the side grafting method is used most frequently. Further to that, trees grown from cuttings or air-layers have no taproot and are apt to be blown down in the first 2 or 3 years. For these reasons, budding and grafting are preferred in the propagation of guavas.

a) Preparation of rootstocks: Fresh seeds should be obtained form clean, ripe fruits, thoroughly washed to eliminate the pulpy materials clinging to the seeds and treated with a fungicide to prevent damping-off before planting in the seedbed. If damping-off is evident as the seedlings emerge, the surface of the media and the seedlings should be treated again with a fungicide.

When the seedlings are 3 to 4 cm tall, they should be planted in small containers for later nursery row planting, or they may be planted in 4-liter containers for the propagation of large seedlings for later use in budding or grafting. Whether to use the nursery row or container-grown seedlings in tree propagation is a matter of preference, convenience, and cost. The result should be producing healthy seedlings.

b) Grafting or Budding: The guava can be grafted or budded by using any accepted method. As an example, the approach grafting method can yield 85-95% success of producing guava planting material. The scion wood or bud-wood should be prepared approximately 10-14 days before cutting, byb removing the leaves from the branch. This practice encourages axillary buds to enlarge and greatly accelerates growth after grafting. Wood that is shedding or has already shed its bark and is smooth greyish green and without leaves gives good results in budding and budgrafting.

The Forkert budgrafting, a modified patch bud method, has been found ideally suited to guava. It always gives the best results (88-100%). A patch size approximately 1 cm x 1.5 cm seems to take better than when a smaller patch or bud is used. The trees from which buds are taken should again be highly vegetative with lush, succulent growth to permit easy separation of buds from the stem. Buds on brown stems with leaf scars are better than younger buds with leaf scars which are distinct and soft.

In Australia, small oval punches about 1 cm on the long diameter are being used on macadamia and guava to remove buds that are fitted into punch-holes similarly created for a perfect match on the stock seedlings. Vigorous seedlings 1.25-2.5 cm thick are used as rootstocks. The bark should slip easily to facilitate insertion of the bud, which is then tightly bound in place with a plastic strip and the rootstock is beheaded, leaving only 6-8 leaves above the bud. About a month later, an incision is made halfway through 5-7.5 cm above the bud and the plant is bent over to force the bud to grow. When the bud has put up several inches of growth, the top of the rootstock is cut off immediately above the bud. Sprouting of the bud is expedited in the rainy season.

Meanwhile, at the Horticultural Experiment and Training Center, Basti, India, a system of patch budding has been demonstrated as commercially feasible. A swollen but unsprouted, dormant bud is taken as a 2 x l cm patch from a leaf axil of previous season's growth and taped onto a space of the same size cut 15-20 cm above the ground on a 1-year-old, pencil-thick seedling during the period April-June. After the bud has "taken", 1/3 is cut from the top of the seedling; 2-3 weeks later, the rest of the top is cut off leaving only 2-3.2 cm of stem above the bud. This method gives 80-90% success if done in July it is only 70% success. In Hawaii, old seedling orchards have been topworked to superior selections by patch budding on stump shoots.

Polyethylene cap has been found instrumental for early sprouting with higher success rate in guava and grafts.

Use of poly cap for early sprouting of grafts

The grafting assay showed that the species P. friedrichsthalianium and P. cattleyanum are compatible with P. guajava cv. Paluma (Figure 2). Approximately 50% of plants survived after grafting. The roots of P. friedrichsthalianium (19.2 g) and P. cattleyanum Red Selection 10 (14.9) presented high weight when compared with the roots of P. cattleyanum Leodoro (7.6 g) and Ya-cy (7.1 g). Above all, these first two rootstocks presented high root vigor and high capacity for root emission. This information agrees with the results obtained for P. friedrichsthalianium by Cassava et al . (1998).

c) Green Wood Stem Cuttings: Green wood stem cuttings or also possible half-ripened wood can be used in cutting propagation. Use a three-node stem cutting with two leafy nodes and a basal node without leaves, or a similar cutting without a basal node. Use an intermittent mist chamber with bottom heat and media temperature maintained at 27°C. The cuttings thus prepared should be treated with a root hormone mixture of 2% indolebutyric acid (IBA) suspended in fine dolomitic limestone or insecticidal talc. The development of the root mass was significantly better with 2% IBA than at the lower concentrations.

The cuttings should be adequately rooted for container transplanting after 6-8 weeks in the mist chamber. The transplant containers need to be large enough to nurse the cutting for about 4-6 months until the plants are ready for field transplant. A good well-drained potting soil should be used, and water supplied adequately. The trees can be easily damaged and growth delayed when plants at this stage are mishandled.

d) Root Cuttings: Roots are an excellent source of propagation material from the fields since the surface roots under normal field conditions readily develop shoots when exposed to light or when slightly injured by herbicides or moving ground equipment. Rooting of greenwood cuttings, with 2-4 leaves retained and the basal end treated with root-inducing compounds and rooted in intermittent mist, has made it possible to produce large quantities of plants in a short time for comercial orchards establishment. It takes anout 6 weeks to 2 months for the cuttings to produce roots. Trees propagated in this manner are just as good as trees propagated by any other means, but the method is applicable only if the parent orchard was started from cuttings rather than having been budded or grafted on a seedling rootstock. However, this method of propagation is quite inadequate in a large nursery operation since the material source is low. It should be noted that there are clonal differences in rooting ability.

e) Marcotting (air layering): Layering is being commercially followed in the southern and western India with very good results. After bending the plant, its branches are covered with soil leaving the terminal portion open. In a few months the rooting of branches takes place which are then separated from the mother plants and planted in the nursery for further sale. Layering is a labor intensive method. A limited number of plants can only be multiplied from a mother plant.

When mother plants are very tall, air layering of shoots is done during the rainy season using polythene and moist sphagnum moss. Use of root promoting plant growth regulator, IBA (3,000 ppm), promotes the rooting of air layers up to 100%. The main limitation of air layering is the poor establishment of air layering in the nursery after detachment from the mother plant. Further, the method is very cumbersome and labor- intensive. Trees produced by marcotting uasually mature earlier than those propagated by budgrafting.

f) Stooling: It is the easiest and cheapest method of guava propagation. Pieces of roots (except the smallest and the very large) are first cut into 12.5-20 cm lengths. The self rooted plants (cuttings or layers) are planted 0.5 m apart in the stooling bed and covered with 5-10 cm of soil that must be kept moist. These are allowed to grow for about 3 years. Then these are cut down at the ground level in March. New shoots emerge on the beheaded stumps. A 30 cm wide ring of bark is removed from the base of each shoot, rubbing the cambium of the exposed portion in May. All the shoots are mounded with the soil to a height of 30 cm. the soil is covered with mulch to conserve the moisture. After a period of 2 months of the onset monsoon, the shoots are detached from the mother plant at ringed portion and planted in the nursery. The shoots are headed back to maintain the root and shoot balance before planting in the nursery.

By following the technique of ringing and mounding of the shoots, second time stooling is done on the same mother stools in first week of September. The rooted stool layers are detached in first week of November. Thus stooling is done twice on the same mother stools in a year. The stooling of a mother stool can be done for many years. With the advancement in its age, the number of stool layers also increases every year. The growth and development of stool layers are better than seedlings.