Prototype of High Yielding Deep Water Rice

Abstract

Modern high yielding lowland varieties such as the IR varieties of IRRI and RD varieties of the Department of Agricultute, are characterized by semidwarf stature, stiff straw, and erect and dark treen leavers. These varieties produce high grin yield only in well irrigated areas. the tradititional deepwater rice has long stem and droopy leaves. They are sensitive to photoperiood and give low grain yield even with fertilizer. Their low grin yields despite of the fertilizer are associated with increased growth of stem and leaves rather than increased grain numberts. Throughmodern rice breeding methods, the Rice Research Institute has produced some high yielding deepwater rice prototypes. These are T 440-57, RD 17, and RD 19 wihich resemble smidwarf high yielding varieties in plant type, but differ in having stem elongation ability, if the water level increases (5 cm. a day) after the seedlings are 35 days old.