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: Soybean, millet, sesame, oats Indian Centre: Rice, sugarcane, arboreum cotton, chickpea –Indomalayan centre: banana, coconut Central Asiatic Centre: Wheat, flax, lentil, pea Near Eastern Centre: Alfalfa, barley, melon Mediterranean Centre: Durum wheat, lettuce, cabbage Ethiopian Centre: barley, chickpea, pea, lentil, sesame, tetraploid wheat South Mexican and Central American Centre: bean, corn, upland cotton, South American Centre: Sea-island cotton, potato, tomato, tobacco –Chiloe Centre: Potato –Brazilian-Paraguayan: 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 –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 Gene bank, in-field, in-vitro 2.Characterize and evaluate 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