How our common bread Wheat originated

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This article was first published in Our College Magazine ("Pranproity") on 23rd January, 2003. Written by me and edited by Dr. A. B. De, reader in Botany, Burdwan Raj College, Burdwan, W.B., India.

Transcript of How our common bread Wheat originated

How our common bread Wheat originated Today Hybrid is very well known term. Now-a-days, most of the cereals, vegetables, meet and milk we consume are hybrid organisms. Hybridisation is done to incorporate the desirable characters of two species in one individual. The hybridisation of plant is done by plant breeders to produce more foods so that demand of food for increasing population is met with. The inter specific hybrids are produced by successful crossing between the species but the hybrids produced are generally sterile, because the chromosome of the parental species are not homologous i.e., the chromosomes of those two species have not linear identical gene sequence . As a result synapsis i.e., side by side association of homologous chromosomes do not occur at meiosis. Eventually gametes are not produced. Inducing polyploidy i.e., multiplying of the diploid set of chromosome of an individual these sterile hybrids are made fertile. The doubling of the chromosome of the hybrids provide the pairing mate to each chromosome at meiosis with normal separation at anaphase resulting in fertile gametes. Fertile hybrid plants are produced due to fusion of these fertile gametes. The common bread Wheat (Triticum aestivum) has been evolved naturally through hybridisation of three wild plants viz. Triticum aegilopides (AA), Aegilops speltoides (BB) and Aegilops squarosa (DD) each with diploid chromosome number 14 (2n = 14). The way by which Wheat has been evolved in nature is given in the following scheme. The present day Wheat is thus a gift of nature and it has been evolved through natural hybridisation of two wild grasses and a wild Wheat plant and polyploidy also has been found to be involved in this process. But what caused polyploidy is not yet known; it may be any physical factor like uv rays of the Sun or anything else.