BP Singh

•Need For Excha~ge of Plant Genetic ResourcesB.P. SinghIntroductionAgriculture evolved some 10,000 years back, with thedomestication of plants of choice and economic importance to man.The result was narrowing down the dependence of human kindfrom an array of wild usable plant resources to a limited anddefined species grown under organised package of agronomicpractices. The era of Green Revolution further confined thevariability in the local cultivars, land races and even withwithdrawal of lesser important crops from particular areas, therebynecessitating the collection and conservation of existing cropspecies, taxa and their relatives.Stages of plant genetic resources for exchangeEvaluation under domestication may be viewed at threedifferent stages(i)(ii)(iii)DomesticationStabilizing semi-domesticated/semi-wild cropsBreeding for improved varieties.The germplasm resources exchange is equally needed at allthe three stages.(i) Domestication: It implies domestication of a crop species innew areas beyond their habitat/home, e.g., Simmondsia chinensis(Jojoba) in area outside southern USA and Mexico.