By JAMES TABABA
Grafting is the fusion of two or more plant parts (scion and rootstock) to form a single growing plant. The scion is the top plant part where the shoots, leaves, flowers, and fruits will eventually sprout, while the rootstock is the established root system where the scion is to be connected.
Grafting is usually practiced as an asexual reproduction to produce clones of plants that are hard to propagate using cuttings, layering, and other asexual propagation methods. Grafting is also commonly performed to clone and propagate excellent performing or rare varieties of fruits and ornamentals. Aside from these reasons, here are a few more practical uses for grafting:
Tolerance to soil-borne diseases
Grafting is effective against soil-borne diseases such as fusarium wilt, bacterial wilts, and root-knot nematodes. Crops susceptible to soil-borne diseases are grafted to resistant plants or varieties.
In the Philippines, tomato that is susceptible to bacterial and fusarium wilt is grafted to resistant eggplant rootstock. Watermelons are also grafted to squash to gain tolerance from fusarium wilt.
Producing off-season crops
Grafting can be utilized to produce crops that are tolerant to certain soil conditions, such as drought and flooding. In the Philippines, tomatoes are a highly seasonal crop. They are abundant during the dry season but only a few supply during the wet season. The limited supply during the wet season results in higher market prices. This is why tomatoes are grafted in eggplant to tolerate flooding and the prevalence of soil-borne disease during the rainy season. This method of production produces off-season tomatoes.
Changing varieties or cultivars
In fruit trees where old varieties become unproductive or susceptible to foliar diseases, the variety can be replaced without uprooting the whole tree through grafting. In some cases, it is practical to change old varieties because newer varieties offer higher yields, better fruit qualities, and improved resistance to pests and diseases.
Grafted fruit trees bear fruits earlier than their seed propagated counterpart. Since the scion comes from a mature parent, it had already skipped the juvenile phase. In avocado and mango, trees from seeds may take six to ten years before fruiting, but when the seedling is grafted, it may only take three to four years to mature.
Dwarfing or restricted growth in height and width is a side effect of grafting. Some farmers prefer dwarf trees because they are easily managed in terms of harvesting fruit, pruning, and spraying of fertilizer and pesticides. Dwarf trees are also suitable for small backyards and garden spaces.
Some trees cannot self-pollinate and need other nearby trees to develop flowers and fruits successfully. In some orchards, male scion is added to the existing female tree to facilitate pollination. This is a common practice in cherries, avocados, apples, and pears.
Multiple flower colors and fruits
In ornamentals, grafting can be done to produce multiple-colored flowers in a single plant. This is usually observed in bougainvillea and gumamela.
Grafting is more than just for cloning and the propagation of plants. Through the years, it has been used in many cultural management and economic purposes.