Varietal Improvement

Abstract

The first efforts at increasing the production of deepwater rice were through varietal improvement, and the early history of deepwater rice research is inseparable from attempts by plant breeders to improve yields. All regions passed through the same phases of varietal collection and purification or, where local germplasm was limited, as in Vietnam and Burma, varietal introduction, which was followed by a hybridization programme. Only rarely were mutation breeding and other special techniques employed during this early phase.