IMPROVEMENT OF GENETIC DIVERSITY OF DENDROBIUM NATIVE ORCHID BALI THROUGH HYBRIDIZATION

Species orchids are the starting point for the production of crosses that have economic value. Therefore, the diversity of the twenty-four Dendrobium orchids that were discovered in Bali by researchers at the Faculty of Agriculture, Udayana University (Ida Ayu Putri Darmawati), is a great potential as a source of germplasm to be chosen as a parent crossing. Through the crossing technique, it is hoped that new hybrid orchids can be produced with certain advantages that consumers will enjoy.

Based on the results of the scoring of the phenotypic and agronomic characters of twenty-four Bali natural Dendrobium, superior and unique characters were found in the accessions of D. macrophylum and D. aphylum, D. fmbriatum, D. heterocarpum, D. secundum, D. stuartii, and D. inflatum. However, due to the different flowering period constraints and the location of the parent broodstock, not all selected brooders can be used as crosses. Some Bali Dendrobium orchids that happen to flower together, such as D. macrophylum and D. inflatum can be crossed.

Actually crossing orchids can be done between types or between clans or genera. The purpose of crossing orchids in general is to get a better quality orchid flowers. In hybridization, the preferred orchid is traits such as color, size, ability, and flower time that are of high quality and attractive. Since orchids began to be known by the European community in the early 19th century, namely during the reign of Alexandra Victoria, the Queen of England in 1830-1901. Many researchers are conducting research and experiments to develop orchids by crossing to get beautiful and high quality new orchid species.

There are several things that must be considered in choosing the flowers to be crossed: (i) from one bunch of flowers a maximum of three flowers are crossed so that energy is only focused on the three flowers; (ii) the best flower bud is the second to fourth flower bud; (iii) flowers that have been in full bloom for 4 days.

The crossing is done in the morning at 07.00 - 10.00, done by selfing and reciprocally by way of polinia moved into the stigma of ripe orchids. The process of crossing is as follows polinia (referred to as male orchid brooders) touched by a toothpick dropped on prepared paper. A toothpick is then inserted into the stigma hole so that the tip is exposed to mucus. With mucus on the tips of polinia toothpicks it can be taken, carried and placed on the same flower stigma or different flowers (as female orchid broodstock).

To avoid interference by insects that might bring polinia to the stigma that has been pollinated first, the flowers that have been crossed are covered in transparent plastic, given the code names of both mothers (male and female) and the date of pollination. The success of pollination is marked by swelling of the flower stalk, then develops into fruit. After the physiological ripe fruit is ready to be harvested. The characteristics of the fruit ready for harvest are the skin color of the fruit is lighter, slightly yellowish and the lines on the fruit become wider.

Orchids, which contain very small orchid seeds, which are between 0 - 2.0 mm and 0.5 - 1.0 mm wide, have around 1,300-4,000,000 seeds per pod or fruit, but the content of food reserves (endospermnya) is very low so it is difficult to germinate. Tissue culture germination can be used to increase the viability and germination of orchid seeds. The success of orchid seed germination is influenced by several factors such as fruit maturity, basic media and the addition of organic matter. Components of tissue culture media must contain macro, micro, vitamin, amino acid, and myo-inositol nutrients. Making bottle orchid seeds on a household scale is enough to use fertilizers that are already circulating in the market such as Growmore, Vitabloom, Hyponex etc. Sterile / contamination free condition is an absolute requirement in making orchid seeds in bottles.