Additional file 2 Figure S1. Correlation coefficients for 12 traits among CSSLs, BC and TC populations in 2007. GN, grain number; HD, heading date; PB, number of primary branches; PH, plant height; PL, panicle length; PP, panicles per plant; PW, panicle weight; SB, the number of secondary branches; SN, spikelet number; SS, seed setting ratio; TGW, thousand-grain weight; and YD, grain yield per plant.