This method was developed by scientists of the Forest Research Institute of Malaysia led by Dr. Darus Ahmad (1992). About 90–100% rootting was obtained from species propagated. This method has been used to produce planting stocks for some plantation establishments and enrichment plantings of dipterocarps in Peninsular Malaysia.
Species under propagation
Important timber species of Malaysia being propagated by stem cuttings are: Dipterocarpus baudii, Hopea odorata, Shorea bracteolata, S. leprosula, S. ovalis, S. parviflora, S. platyclados S. singkanang, Alstonia angerstiloba and Endosperum malaccense.
Sources of cuttings
Cuttings were collected from juvenile plants (one-year old seedlings and sprouts on stumps of less than 10-year old trees). In order to perpetuate a broad genetic base, seeds were collected from several trees of each species at different locations in Malaysia. These seeds were then grown in nursery beds or in plastic bags, serving as a seedling hedge orchard, from where stem cuttings were taken.
Preparation and treatment of cuttings
Top shoot cuttings about 10 cm long having three well-developed leaves or sometimes one nodal stem cuttings were made with slanting angle cut through a node using a very sharp knife. Species with a bigger leaf such as E. mallaccense mature leaves were trimmed back to half their leaf area.
Plate 6. A one-nodal stem cutting, cut at slanting angle through the node.
The base of each of the newly collected cuttings was dipped in Seradix powder (0.8% IBA) just before planting in a saturated river sand rooting medium. After planting, the propagation bed was covered with a box made from plastic sheets, to keep the humidity at about 80–90% and maintain the temperature at about 25°C–28°C. A green-coloured shade cloth (75% shade) was placed on top of the plastic sheet to filter-off excessive sunlight.
Plate 7. Misting structure covered with box made of plastic. Green net is placed on top to filter out sunlight, thus maintain the desired levels of humidity and temperature.
Spray mist was supplied by an automatic mist spraying mechanism in spurts of 30 second duration at 5 minute intervals. The timer activates the mist at 6:00 a.m. and shuts off at 6:00 p.m.
Roots developed within a 4–6 weeks period.
Hardening
Rooted cuttings were transplanted in plastic bags filled with forest topsoil × river sand (1:1), then placed in a hardening bed which was covered by a box made from plastic sheets and green-coloured shade cloth. The plants were watered by hand water sprinkler every two hours during day time for a period of 4 weeks. Subsequently, frequency of watering was reduced to 3 times a day, and the green-coloured shade cloth removed. After another 4 weeks, the potted rooted cuttings were transferred to the nursery bed partially shaded by one layer black-coloured shade cloth. The plants were kept under this condition, and properly cared for until they were vigorous enough to be outplanted in the field.
Plate 8. Potted rooted cuttings ready for outplanting
Marked variation in rooting success among species was observed in Dipterocarpus chartaceus (60–80%), Shorea bracteolata (100%), Anisoptera scaphula (80%), and Shorea leprosula when treated with 100 ppm, 500 ppm, and 2000 ppm of tale preparation of IBA, respectively (Srivastava and Manggil, 1981).
Preparation of propagating bed
Two types of propagating beds were used, viz. concrete beds measuring 1.2 m (W) × 3.35 m (L) × 0.4 m (deep) with the bottom sloping to a central drain. Wooden boxes, measuring 0.6 m × 0.6 m × 0.2 m (deep) with drainage holes at the base were placed on the concrete. A wooden frame was erected around the concrete bed and the boxes. Wooden planks of suitable size were inserted in the medium in the bed to divide it into different compartments for various treatments in order to check the hormone flow from one treatment to the other during the experimental period. Transparent polyethelene sheet was fixed on the sides of the frame and the roof was covered with gunny sacks which were always kept moist, in order to create high humidity by reducing air movement and rate of evaporation.
The rooting medium was composed of sieved river sand with 45.5% gravels, 31.0% very coarse sand, 18.1% coarse sand, 3.8% medium sized sand, and 1.6% fine sand, underlain by coarse granite chips.
Source of cuttings
The cuttings were prepared from leader shoots and branches of vigorously growing young plants raised from seeds in the greenhouse. The species, and age of the plants were: Anisoptera scaphula (27 months), Shorea bracteolata (12 months), Shorealeprosula (10 months) and Dipterocarpus chartaceus (10 months).
Preparation and treatment of cuttings
The cuttings were about 10 cm long with few leaves retained, but half of the leaf blade removed. Terminal buds were clipped off, but the lateral buds, active or dormant, were retained along the entire length of the cuttings. Using a very sharp pruning shear, the cut at the basal end was made oblique angle to ensure a greater surface for absorption of hormone and more area for callus formation and subsequent rooting.
Immediately after the cuttings were separated from the stock plants, their bases were dipped into a tale preparation of indolebutyric acid (IBA), in four concentrations viz., 100 ppm, 500 ppm, 1000 ppm and 2000 ppm. The cuttings were then inserted obliquely into the rooting medium, pressing firmly around the cuttings.
Watering schedule
After planting, watering was carried out immediately to create high humidity around the cuttings and ensure an adequate amount of moisture in the rooting zone. Mist was created by means of three manually controlled misting heads placed about 90 cm apart in the propagation bed. In the boxes, watering was done with a fine spray. During the first seven days after planting, misting was done for five minutes in every half-hour between 7:30 a.m. and 6:00 p.m. In the next 15 days, misting was done at hourly intervals for five minutes, from 8:00 a.m. to 6:00 p.m. During the rest of the experimental period, the cuttings were watered for five minutes at two hour intervals. At the same time during these periods, the gunny sack on the roof of the bed and boxes were constantly kept wet. The mean relative humidity was about 66% and 68% in the bed and boxes, respectively, and the minimum and maximum temperatures were 23°C in the air and 28°C in the rooting medium.
Rooting success
Rooted cuttings grown in the wooden boxes were transplanted into polyethelene bags three months after planting. Rooted cuttings from the concrete propagating bed were transplanted in polyethelene bags five months after planting.
The highest rooting percentage in Ani soptera scaphula was obtained in cuttings treated with 1000 ppm, IBA (80%) and best root systems were developed under 2000 ppm IBA. Almost all cuttings developed prominent callus tissue at the basal end, and new shoots appeared much earlier than roots.
An average of 91.2% rooted in Shorea bracteolata cuttings which also produced green buds between the sixth and seventh weeks in the bed and between the fourth and sixth weeks in the boxes. The treatment with 500 ppm IBA produced the most abundant and uniform root system, followed by the treatments with 1000 and 100 ppm IBA.
Only about 18% of the Shorea leprosula cuttings rooted when treated with 2000 ppm and 1000 ppm IBA.
In Dipterocarpus chartaceus, most of the rooted cuttings produced green buds between the fourth and sixth week after planting. About 32% of the cuttings rooted survived. Cuttings treated with 100 ppm IBA produced vigorous root systems.
Hardening
Rooted cuttings were transplanted in polyethelene bags filled with ordinary nursery soil. They were placed under shade inside the greenhouse, watered regularly to prevent wilting. After 8 to 10 months, the rooted cuttings were outplanted in the field.
Cuttings taken from coppice shoots of Agathis dammara and Fagraea frangrans, and cuttings from juvenile plants of Shorea talura, Anisoptera sacphula, Podocarpus imbricatus, and Vatica wallichii were rooted successfully in Malaysia (Momose, 1976).
Preparation of rooting bed
Washed coarse sand was used to fill up the rooting bed (1m × 5m × 0.6m deep). An automatic mist-spraying mechanism was set up, with the mist activated in spurts of 30 seconds duration at 5 minute intervals. An additional timer was added to activate the mist cycle in the morning (6:00 am) and to shut it off in the evening (6:00 pm).
Relative light intensity was maintained below 10% and temperature stabilized between 25°C and 28°C in the cutting bed by shading it with green coloured shade cloth (50% shade).
Sources and preparation of cuttings
Cuttings 15–20 cm long, consisting of several nodes with leaves attached and short (one-leaf-bud) cuttings, consisting of one node with its leaf and axillary bud and part of the internode below were used in the experiment. Cuttings were taken from branches of mature trees, coppice shoots from bases of trees and from juvenile plants (seedlings). The bark of the stem was slit longitudinally on the side opposite the leaf-cum-axillary-bud to expose conductive tissue along the whole length of the cutting to facilitate water uptake. The cuttings were buried in the rooting medium, so that the whole of the stem (with leaves detached), the axilliary bud and the base of the leaf-stalk were below the surface of the medium.
Rooting success
Cuttings taken from branches of mature trees all failed to root. Long cuttings taken from coppice shoots of Agathis dammara and Fragraea fragrans and from juvenile plants of Podocarpus imbricatus rooted successfully.
Short cuttings taken from coppice and seedlings of Shorea talura, Anisoptera scaphula, Vatica wallichii and Agathis dammara rooted successfully.
Hardening
After the axillary buds developed into shoots, the cuttings were transplanted to pots. Regular cultural maintenance was applied to rooted cuttings. The shoots were 20–25 cm tall after one year, when they were planted in the field.
