The demand for planting materials continues to increase every year especially now that the greening program has gained greater attention and support from the government, non-government organizations and other groups/individuals. These planting materials may be in the form of seeds, seedlings, cuttings, and wildlings.
The increased demand calls for the intensified production of quality planting materials. This will support the government’s effort for environmental services, enterprise development and self-sufficiency not only for major forest products, but also for fruit, ornamental, and medicinal crops.
However, the quality, quantity and availability of the planting materials at the right time are critical issues that need to be addressed in order to attain success of the massive greening program. These issues can be resolved by strengthening the production of planting materials, the establishment of nurseries through the involvement of various stakeholders, and adoption of appropriate technologies.
I. METHODS OF PROPAGATION
Planting materials may be propagated either from seeds or vegetative parts of plants.
A. SEEDS OR SEXUAL PROPAGATION
A seedling is a nursery-grown planting material developed from a seed. While most of the nursery-grown seedlings are healthy, some may have defects/ imperfections. These defects may or may not be visible to the eye.
Healthy seedlings come from superior seeds. Superior seeds come from selected mother trees. From such source, healthy seedlings ensure higher survival rate and will grow to be vigorous and productive trees. A mother tree has the following characteristics:
For fruit trees, a mother tree has:
- Strong and hardy trunk/bole
- Erect to spreading branches
- Regularity in bearing fruits
- High yield
- Free from pests and diseases
- High percentage of the edible portion of fruits has:
- - excellent eating quality
- - skin that easily peels off and does not adhere to flesh
- - seeds that does not also adhere to flesh
Considering the value of healthy seedlings, planters are encouraged to produce/raise these on their own. Although this entails a higher cost, producing one’s own healthy seedlings will eventually prove to be a sound investment.
Know a healthy seedling when you see one
A seedling may appear healthy at first glance but, a closer look can prove otherwise. A healthy seedling has the following characteristics:
Ensure healthy seedlings thru proper procedures/ technologies
Healthy seedlings can be produced through proper procedures and technologies.
There are three ways to collect fruits/seeds from selected mother trees:
|Other factors to consider:
Process the seeds properly to avoid damage and attain high percentage germination.
Extract the seeds from the collected fruits and immediately dry them for easier storage and transport. Sun or air dry the seeds to save them from fungal and micro-organism infection and insect attack.
In addition, separate the seeds from impurities through any of the following methods:
Seed testing is done to determine the quality and the capability of seeds to germinate into healthy seedlings. This can be done through the following:
- Viability test. This is done by germinating randomly sampled seeds using appropriate pre-germination treatment to determine how many will germinate.
- Seed health test. This is done through visual or laboratory examination of the seeds to identify disease-causing organisms, such as fungi, bacteria, viruses, as well as animal pest, such as worms and insects.
Seed Storage and Handling
Seed storage is a technique where seeds are kept under favorable environmental conditions to maintain seed viability. This is to keep excess viable seeds for future use when seeds are no longer available for collection.
Determine the moisture content (MC) of the seeds if they need further drying or are ready for storage without losing their viability. In general, orthodox seeds (long-lived or with more than a year of viability) require an MC that ranges from 6% to 12%, while recalcitrant seeds (short-lived or with less than one year viability) need an MC that is greater than 12%, depending on
the species. (Refer to Annex B for moisture content determination)
Some other requirements in storing and handling seeds:
- For seeds stored under room temperature: spread or place them in cloth sacks.
- For seeds stored in cold storage: keep the temperature at about 10DC for orthodox and about 15°C for recalcitrant.
- For seeds stored in sealed container: dry the seeds to their desired moisture content to avoid deterioration.
- When transporting, place seeds in sealed containers or securely wrap them in wax paper.
When the seed starts to sprout, germination is taking place. Generally, germination occurs from 3 days to 2 weeks after sowing. However, some seeds germinate longer, depending on species.
- Treatment before germination
Seeds with hard coats require some treatments for faster and uniform germination. These include any of the following:
- breaking of hard seed coats
- cold water soak
- hot water soak
- alternate hot and cold water soak
- dry heat treatment
- acid and other chemical treatments, such as soaking in sulfuric acid
(Refer to Annex C for Seed Technology)
- Methods of sowing
- Sowing in seedboxes
Benguet pine (Pinus kesiya), Bagras (Eucalyptus deglupta), Agoho (Casuarina equisetifolia), Kaatoan bangkal (Anthosephalus chinensis), and other species with very small or fine seeds (less than 1 cm in diameter) are sown only in seedboxes. Cover the seeds with fine sand, just enough to ensure surface cover.
- Direct sowing or sowing in seedbeds
Large seeds (more than 1 cm in diameter) are either sown in seedbeds or directly in plastic bags and other containers. Examples of these are Ipil (Intsia bijuga), Narra (Pterocarpus indicus), Ma-hogany (Swietenia macrophyiia), Talisay (Terminalia catappa), Teak (Tectona grandis), Lumbang (Aleuhtes moluccana), among other species. Simply press the seeds into the soil until they are half covered.
The preferred sowing materials or germination soil mix consist of 50% sieved washed river sand and 50% top garden soil.
Water the sown seeds using a sprinkler with fine holes close to the soil to avoid dislodging of seeds. Continue watering every day - early in the morning or late in the afternoon — until the seedlings are ready for potting. For very fine seeds, water them very carefully so that the seeds are not eroded.
- Sowing in seedboxes
- Preparation of potting materials
Sterilize the soil before using it as potting material to avoid problems with soil-borne diseases, such as damping-off and root rot. This is done using any of the following methods:
- heat the soil over a fire for about 15 minutes
- apply chemical disinfectant (fungicide)
- pour boiling water
- spread the soil under direct sunlight in a clean area for one or two days.
- Seedlings from seedboxes or seedbeds
Transfer the seedlings from the seed boxes or seedbeds to plastic bags or other containers. This will provide them with adequate space to grow and develop. In transplanting the seedlings, consider the following:
1. Transfer the seedlings from the seedboxes or seedbeds when the second pair of leaves has fully developed. 2. Lift the seedlings with a trowel only when they are already firm and the soil is moist. 3. Plant the seedlings in plastic bags or other containers. 4. Water the seedlings immediately after transplanting. 5. Keep seedlings shaded for sometime until they have established themselves. 6. Set aside poorly developed seedlings for treatment to improve their quality, but discard infected ones.
Wildings are seedlings that grow naturally in the forest. These can be used when nursery-grown planting stocks or seeds are lacking or not available.The following are the steps on how to gather and transplant wildlings:
1. Collect wildlings when the soil is moist to minimize damage of roots. 2. Gather the wildlings by simply lifting them with the aid of a bolo or shovel. 3. Leave a ball of earth attached firmly around the roots. 4. Wrap the ball of earth with a banana sheath or a plastic bag with holes. 5. Transfer the balled wildings to a shaded portion of the nursery. 6. Let them develop before planting in the field.
Wildlings of Narra (Pterocarpus indicus), Mahogany (Swietenia macrophylla) or Ipil-ipil (Leucaena leucocephala) are lifted with the aid of a bolo or sharpened stick, leaving balls of earth attached firmly around their roots. For dipterocarp species, such as White Lauan (Shorea contorta), Red Lauan (Shorea negrosensis), and Bagtikan (Parashorea plicata), select wildlings with more than 7 mm diameter and height of 15-50 cm.
- Seedlings from seedboxes or seedbeds
B. VEGETATIVE OR ASEXUAL PROPAGATION
Instead of seeds, this method of propagating trees uses plant parts, such as stems, leaves, roots, twigs, single cells, and tissues as initial material. This is done especially in plants that do not fruit regularly (seed-off) or when earlier fruiting is desired.
Some of the common techniques are propagation by cuttings, grafting, marcotting, and budding.
Propagation by cutting is commonly used in most forest tree species such as Narra (Pterocarpus indicus), Mahogany (Swietenia macrophylla), Yemane (Gmelina arborea), dipterocarp and bamboo species (Refer to Annex D on how to raise bamboo cuttings). Grafting, marcotting and budding are used for most fruit trees such as Pomelo (Citrus grandis), Santol (Sandoricum koetjape), and Mango (Mangifera indica).
A cutting may be a portion of a stem, root or leaf of a donor plant. This is placed under favorable condition to induce the development of roots and shoots. There are several effective propagation systems in which the rooting of stem cuttings are successful.
Rooting Stem Cuttings Using Non-Mist System
This technique is cheaper and a more practical way of propagating planting materials through rooting stem cuttings. The basic components of this technique are non-mist propagation chamber, rooting media, root containers and hand-mist sprays.
Connecting two pieces of living tissues together so that they unite and eventually grow and develop as one plant is called grafting. This propagation method is used when cutting is not applicable. It is also used to:
This is a propagation method which includes the development of roots on a stem while it is still attached to the parent plant.
The procedures for this method are:
Budding is done when the scion is reduced in size to contain only one bud and a small portion of the bark, with or without wood. This process is applied or used in small plants.
A scion is a detached living portion of a plant, such as a bud, to be attached to a rootstock in the budding or grafting methods.
There are two types of budding:
Tissue culture is an alternative means of propagating superior planting materials in a sterilized laboratory using a piece of a plant part. Grown either in test tube, bottle or other containers, they are provided with appropriate rooting media under controlled conditions of light and temperature.
|Tissue culture can produce a larger number of quality seedlings. This method however, is more expensive.|
To venture into tissue culture, consider the following steps:
- Select a mother tree in the natural forest or in plantations.
- Collect cuttings and/or marcotted branches from the mother tree which will be the source of young shoots (explants).
- Sterilize young shoots using disinfectants.
- Inoculate the explants into a culture medium (agar). The culture me¬dium will supply the nutrients needed by the plants to grow and develop in the test tubes or bottles.
- Induce the explants to form multiple shoots by using growth hormones.
- Provide cultures in the laboratory with lights and low temperature. Acclimatize the microshoots with nursery conditions while growing inside the bottles.
- Upon reaching 1.5 to 2 inches height, outplant the microshoots in trays that contain sand or soil. Enclose the tray in a plastic bag in order to maintain high humidity and low temperature. Once rooted, the plantlets can be exposed to normal growing conditions like any kind of seedlings.