Transcript 1 Plant Genetic Resources

Origin of Some Domestic animals and Plant Species
Center of Origin
NI Vavilov (1926), a russian Botanist coined the terms of center of
diversity and center of origin.
• primary centre of origins
– Areas where crop plants were domesticated
• Secondary Centre of origin
– areas where variation continued after domestication
Center of Diversity
Area where vast genetic diversity existed for a cultivated crop species
(NI Vavilov 1926)
Centers of diversity
• Chinese Centre:
• Indian Centre:
– Indomalayan centre:
• Central Asiatic Centre:
• Near Eastern Centre:
• Mediterranean Centre:
• Ethiopian Centre:
• South Mexican and
Central American Centre:
• South American Centre:
– Chiloe Centre:
– Brazilian-Paraguayan:
Soybean, millet, sesame, oats
Rice, sugarcane, arboreum cotton, chickpea
banana, coconut
Wheat, flax, lentil, pea
Alfalfa, barley, melon
Durum wheat, lettuce, cabbage
barley, chickpea, pea, lentil, sesame, tetraploid
wheat
bean, corn, upland cotton,
Sea-island cotton, potato, tomato, tobacco
Potato
Peanut, pineapple, rubber
Genetic diversity:
Variation that exists within the genetic constitution (nucleotides,
genes, chromosomes, or whole genomes) of an organism
Phenotypic Diversity
Refers to the variation of the physical traits, or phenotypic characters
of the organism, such as differences in anatomical, physiological,
biochemical, or behavioral characteristics.
– the phenotypic characters represent an important measure of the
adaptation of the organism to its environment because it is these
phenotypic characters that interact with biotic and abiotic (i.e.
living and non-living) factors of the environment.
Plant Genetic Resources
• Plant germplasm
– is the genetic source material used by plant breeders to develop new
cultivars
– Genotypes of particular species, collected from different sources and
geographical origins, for use in plant breeding.
• Sources of Plant germplasm
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Wild relatives
Land races & primitive cultivars
Obsolete cultivars
Advanced breeding lines & other products of plant breeding
program
– Current cultivars
• Thus the germplasm of a crop may be defined as
– The sum total of hereditary material i.e. all the alleles of various
genes, present in a crop species and its wild relatives
Role of Germplasm in crop Improvement
• Source of Novel Genes
– Disease resistance genes in wheat (from A, AB and D genomes)
– Drought, Salinity and heat tolerance in wheat ( from AB and D genomes)
– Nutritional quality in wheat
– Fibre strength gene in cotton (from lintless cotton)
ENSURING BETTER FOOD SECURITY
Germplasm Management
1. Conserve
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Gene bank, in-field, in-vitro
2. Characterize and evaluate
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Morhological
Phenological
Physiological
Yield & Yield Components
Pathological
Entomological
Chemical
Molecular/ DNA
3. Understand
4. Use (‘utilization’)
Agencies engaged in plant breeding
• Asian vegetable Research and Development Center (AVRDC)
Taiwan
– Cabbage, Pepper, tomato, soybean & Mung bean
• International center for Agriculture Research in Dry Areas (ICARDA)
Syria
– Barley, Chick pea, faba bean, tropical forages, lentil & wheat
• International center for wheat and maize Improvement (CIMMYT)
Mexico
– Maize, triticale and wheat
• International center for Tropical Agriculture (CIAT) Colombia
– Dry beans, cassava, rice and tropical forages
Agencies engaged in plant breeding
• International Crop Research Institute for the Semi Arid Tropics
(ICRISAT) India
– Chickpea, millet, peanut, pigeon pea and sorghum
• International Institute of Tropical Agriculture (IITA) Nigeria
– Cassava, cocoyam, cowpeas, lima bean, maize, pigeon pea,
rice, soybean, sweet potato, winged bean and yam
• International Potato Center (CIP) Peru
– Potato and sweet potato
• International Rice Research Institute (IRRI) Philippines
– Rice
Genetic diversity:
refers to any variation in the nucleotides, genes, chromosomes, or whole genomes of
organisms
Genome:
the entire complement of DNA within the cells or organelles of the organism
Genotype:
the genetic constitution of an organism that results from the arrangement of the DNA
within the cell or organelles.
Genotypic Variation:
the variation that exists between the genetic constitution of different individuals.
Phenotypic Variation:
the variation of the physical traits, or phenotypic characters of the organism, such as
differences in anatomical, physiological, biochemical, or behavioral characteristics.
Phenotype:
the physical constitution of an organism that results from its genetic constitution
(genotype), and the action of the environment on the expression of the genes