Rice adaptation to light and temperature stresses is the basis of stable yield. Few simple and easy techniques exist to test rice germplasm for tolerance for these stresses.
We screened rice germplasm for shading tolerance using the method of Murty (1992). We divided the identified varieties into two groups during elongation stage. One group was placed in natural light, the other in the shade (1/5 natural light). After 14 d, the dry weight of the two groups was measured at the booting stage. The ratio of dry weight under shading to that under natural light was used as the shading tolerance index.