The relationship between the number of grains per spike (GpS) and the TGW was traditionally found as being negatively correlated [1–3]. However, the simultaneous selection of favored haplotypes for one plus neutral ones for the other or otherwise favored haplotypes for both traits has changed the correlations from negative to neutral or even positive . Therefore, no significant correlation was observed between TGW and GpS in the collections of Chinese landraces , French winter wheat cultivars  or CIMMYT-derived spring cultivars and lines [6, 50], while significantly positive correlations were observed in Chinese modern cultivars .