Study on Relationship Between Stem Characters and Output in Early Janopica Rice of Cold Region

180 early janopica rice varieties(or lines) were studied in special ecological environment of cold region.The relations of the stem characters and output were discussed systematically.The main results were as follows:In a restricted range,controlling length of 3 rd internode from the top,increasing length of 1 st and 2 nd internode from the top could raise yield and benefit for choosing length of 1 st and 3 rd internode from the top.In configuring internode thickness,increasing based internode thickness based on ensuring the thickness of 1 st internode from the top was beneficial to high-yielding.Adding dry weight of basal internode(DWBI),dry weight of pedicle sheath(DWPS),dry weight of per plant was in favor of high-yielding.Raising biomass by appropriately increasing plant height and pole length might be the direction of super-high rice breeding in the future.DWBI,thickness of 2 nd internode from the top,DWPS and length of panicle neck were enough to stand for the whole amount of information about twelve stem characters when making comprehensive evaluation on stem characters.