Abstract

                                An attempt is made in the following article to discuss some of the main aspects of crop improvement, with particular reference to paddy and the experience gained at the Aduthurai Agricultural Research Station. Even after a superior strain or variety of crop plant is evolved, the plant breeder cannot rest in peace. The requirements of people and the agricultural conditions are continually changing and as such the plant breeder must be alert to the changing conditions. The strain itself may undergo natural changes and may deteriorate. Ordinarily, the complaints of deterioration from ryots are due to (1) seed admixture due to careless handling and (2) extension of cultivation of the strain to localities not suited to them. Rarely the deterioration is attributable to genetic causes, viz., segregation to inferior type. The admixture may take place in nurseries, transplant fields, threshing floors and seed store. If the deterioration is due to genetic causes, the breeder resorts to reselection to establish purity.

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