|Basic Concepts in Environment, Agriculture and Natural Resources Management: An Information Kit (International Institute for Rural Reconstruction (IIRR))|
Plant genetic resources are traits or characteristics, passed from generation to generation through inheritance, that are actually or potentially useful. For each disappearing plant species, up to 30 animal or insect species directly or indirectly dependent upon it may also be lost. If plants do not exist, animals cannot survive.
Uses of plant genetic resources
Provide humanity with basic needs like food, medicine, shelter, clothing, fertilizer, religious articrafts, fiber, income, craft materials, energy, feed for animals, etc.
- Provide plant breeders materials needed to produce new plant strains/breeds to adapt to a changing environment.
Examples of plant diversity in the Philippines
The Philippines, a country located in the humid tropics, is one of the richest sources of plant diversity.
- The Tagalog folk song Bahay Kubo mentions a total of 18 vegetables grown around a Filipino backyard.
- Mt. Makiling in Laguna contains more plant species, approximately 3,000, than the entire country of Canada.
- Before the advent of the Green Revolution, there were approximately 3,000 traditional rice varieties found in the Philippines. In 1987, there are only about 100 traditional rice varieties that remain in scattered areas in the Philippines.
- The Hanunoos, a small tribal group in Oriental Mindoro, cultivate at least 21 traditional rice varieties.
- There are at least 100 distinct accessions of cassava (introduced in the country several centuries ago so they have already been acclimatized) found at the Philippine Root Crops and Training Center in Baybay, Leyte.
Threats to plant genetic resources
Habitat destruction -- the replacement of entire habitats by human settlements, grazing lands, commercial/agricultural lands and industrialization.
As of 1988, there were only 6.5 million hectares of forest area compared to 1969 wherein there were 10.5 million hectares of forest.
Overexploitation -- the intensive harvesting of plants and the extent to which these plants or plant products are traded.
The export of cycads, orchids, cacti, other succulents and ferns is a major threat to plant genetic resources.
Agricultural development - the introduction of new breeds of plants (e.g., hybrids) and monoculture production systems.
In the Philippines, 4,000 varieties of rice were planted every cropping season in 1964. Today, only eight major varieties of rice are planted in 8, percent of irrigated rice lands.
Effects and consequences of the loss of diversity of plant genetic
Tungro virus destroyed JR-8 (a rice variety developed by the International Rice Research Institute) in 1971 and has become prevalent in many areas where IR seeds are planted in the Philippines. This is due to monocropping of IR seeds.
- The abundance of one type of crop (monocropping) results in the proliferation of pests, forcing farmers to use chemical pesticides. However, pests easily acquire resistance to chemical pesticides. In 1 93O, only 30 pests had resistance to chemical pesticides; by 1 980, over 430 pests had acquired resistance to chemical pesticides.