Studies on panicle shading of rice with different row directions and spike types

The panicle shading of rice with different row directions and spike types was studied.It showed that the panicle shading time in N-S row was longer than that in W-E row on critical altitude.In the morning,the altitude of panicle shading moved from the spike top to bottom in N-S row.As to W-E row,the altitude of panicle shading was same to the N-S row at first,then the altitude of panicle shading from bottom to critical altitude.The panicle shading length was from zero to spike length.