View source for Crop origins and evolution

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The origins of agriculture and domesticated crops are intertwined, and the change from a hunter-gatherer mode to tillage, sowing and harvesting was one of the major technologcal innovations of humankind. There is good evidence that this occurred some 10,000 years ago in several different locations, and involved the [[domestication]] of wild-relatives of the major crops (see [[History of Agriculture]]).
[[Image:Teosinte_corn.jpg|frame|Over time, selective breeding modifies teosinte's few fruitcases (left) into modern [[corn]]'s rows of exposed kernels (right). (Photo courtesy of John Doebley.). From: Genetically Modified Corn— Environmental Benefits and Risks Gewin V PLoS Biology Vol. 1, No. 1, e8 doi:10.1371/journal.pbio.0000008]]
Domestication involves changes in the genetic makeup and morphological appearance of plants (and animals). These changes occur because people select the variations of a wild plant that best suit their needs. If the desired features can be passed to offspring, over generations of planting and harvesting, the strains of plants grown change. Despite the fact that these domesticated varieties of plants are preferred over their original forebears, the wild-relatives of crop plants continue to be an important resource. Reserves of wild plants offer a pool of genetic diversity. Traits of plants that might have been lost in domestication, sometimes become crucial for protection of domesticated crops from stress and disease (see [[Plant breeding]]). Maintaining wild strains for their gene pool helps ensure food security. Knowledge of crop origins is thus of considerable practical importance, even when these original strains are no longer harvested as crops. 

Development today of new crops (such as perennial alternatives of currently used annual staples) has  potential value in helping  meet serious current agricultural challenges such as the need for water use efficiency, better management of land [[salinization]], and [[soil conservation]].