Sumber Genetik

GENETIC RESOURCESPLANT BREEDINGAGR 3204

GENETIC RESOURCES: Resources that contain all genetic variability found in a particular plant speciesThis includes its wild relatives; most of them may have traits useful to breeders.

GERMPLASM: Overall genetic materials possessed by the plant species

Categories of Genetic Resources (Hawkes, 1983)CropsCurrent commercial cultivars.Old commercial cultivars - no longer planted commercially.Breeders seeds.Mutants from induced or spontaneous mutations.

Land RaceUsually from isolated areas or farms. Primitive crops, usually possessing high variations and grown in mixtures of genotypes, and sometimes species.

Categories of Genetic Resource (Cont.)Weedy RacePlants that originated from same progenitor of the crop species, but possess weedy traits, such as small stem.

Capable of invading open fields rapidly, even with low soil fertility.Wild speciesSpecies from the same genus that could be crossable to a certain crop species.

Categories of Genetic Resources (Cont.)Vavilov (1887-1941), a Russian botanist studied diversity and distribution of plants in the world from 1920s to 1930s, and found that:There are higher levels of diversity in certain parts / regions in the world for certain kinds of plant. Revealed eight centres of origin for main crops.

CENTRES OF ORIGIN AND CENTRES OF PLANT DIVERSITY

Cereal and legumes: eg: Soybeans (Glycine max)Roots, vegetables eg: Radish(Raphanus sativus) chinese cabbage (Brassica rapa chinensis)Fruits and nuts eg: Oranges (Citrus sinensis), litchi (Litchi chinensis) Sugar, drug plants eg: Tea (Camellia sinensis), sugar cane (Saccharum sp.)

1. Chinese Center (China)

Distribution and origin of plants2. Indian CenterCereal and legumes eg: Rice (Oryza sativa), chick pea (Cicer arietinum)

Vegetables and tubers eg: Egg plant (Solanum melongena) Cucumber (Cucumis sativus)

Sugar, oil, fiber plants eg: sugar cane (Saccharum spp.), kenaf (Hibiscus cannabinus)

Spices eg: Black pepper(Piper nigrum)

Distribution and origin of plants2a. Indo-Malayan CenterFruits eg: Pomelo (Citrus maxima), Banana (Musa spp.) Coconut (Cocos nucifera), mangosteen (Garcinia mangostana), Durian (Durio zibethinus)Oil, sugar, spice plants eg: Nutmeg (Myristica fragrans),Cloves (Syzygium aromaticum)

3. Central Asiatic CenterGrains and legumes eg: Wheat(Triticum aestivum), Pea (Pisum sativum)Vegetables eg: Carrot (Daucus carota), spinach (Spinacia oleracea)Fruits eg: Apple (Malus pumila), grape (Vitis vinifera)

Distribution and origin of plantsCentral Asia4. Near Eastern Center Grain and legumes eg: Wheat (Triticum aestivum), Barley (Hordeum vulgare)Fruits eg: Melon (Cucumis melo), Pomegranate (Punica granatum)Forage plants eg: alfalfa (Medicago sativa)

Distribution and origin of plantsNear East5. Mediterranean CenterCereal and legumes eg: Wheat (Triticum durum), oats (Avena sativa), Broadbean (Vicia faba)Oil and fiber plants eg: Olive (Olea europaea) , black mustard (Brassica nigra)Vegetables eg: Cabbage (Brassica oleracea)Ethereal oil and spices eg: peppermint (Mentha spp.), thyme (Thymus mongolicus)

Distribution and origin of plants6. Abyssinian/Ethiopian (African) CenterGrains and legumes eg: Wheat (Triticum durum), Barley (Hordeum vulgare)Misc: Coffee (Coffea arabica), okra (Abelmochus esculentus)Oil palm (Elaeis guineensis)

Distribution and origin of plants/Ethiopian (African)7. South Mexican and Central American CenterGrain and legumes eg: Corn (Zea mays), Common bean (Phaseolus vulgaris)Melon plants eg: Pumpkin (Cucurbita spp.)Misc: Chilli (Capsicum annum), cocoa (Theobroma cacao)

Distribution and origin of plantsSouth Mexican & Central American Center8. South American (Peruvian-Ecuadorean-Bolivian) CenterRoot tubers eg: Sweet potato (Ipomoea batatas), Potato (Solanum tuberosum)Vegetable crops eg: Tomato (Solanum lycopersicum)Fruits and misc eg: Papaya (Carica papaya), Tobacco (Nicotiana tabacum)

Distribution and origin of plants8a. Chilean CenterPotato (Solanum tuberosum)

Distribution and origin of plants8b. Brazilian-Paraguayan CenterCassava (Manihot esculenta)Groundnut (Arachis hypogea)Cocoa (Theobroma cacao)Rubber (Hevea brasiliensis)Pineapple (Ananas comosus)Passion Fruit (Passiflora edulis)

Distribution and origin of plantsGERMPLASM CONSERVATIONDeforestation Lost of wild species and weedy races.

Use of modern varieties Lost of land races, primitive crops and weedy races.

Development Lost of land races, primitive crops varieties, etc.

Therefore, conservation is needed to conserve crop genes and genotypes, to prevent genetic vulnerabilityErosion or loss of genetic resources happened and is continuously happening at a serious rate due to: STEPS IN GERMPLASM CONSERVATION1. Exploration Exploration is done to understand the crop distribution.Plant collection is conducted to obtain samples that consist the maximum genetic diversity.Where?Native habitats of selected cropFarm where crop is planted, including small farmMarketOther entities/ institutions

2.CollectionRandom samplingTo obtain variation that represents population of the crop.Selected samplingDone for plants with specific character. The collection may not represent the actual variation. Therefore, selected sampling has to be done concurrent with random sampling.

STEPS IN GERMPLASM CONSERVATION (cont.)STEPS IN GERMPLASM CONSERVATION (Cont.)3.Maintenance / ConservationIn situ grown in natural habitatMaintain the original forest ecosystem, grassland, Vavilovs centre of diversity, forest parks.

Maintenance / Conservation (Cont.)

b)Ex-situCollectionsSeed bankRequirement: Cold room, 10oC Relative Humidity, 2-5%

Living PlantsBotanical GardensArboretumField genebanks

Maize seed bankarboretum3. Storage (Conservation)

b)Ex-situ (Cont.)Pollen storageRequirement: Cold room, 10oc to - 20oc Relative Humidity, 8 -25%In-vitro method- Tissue culture slow growth- Cryopreservation- Liquid nitrogen (-196oc)