Regrowth and biomass allocation of dual-purpose winter wheat under two clipping heights

A greenhouse experiment was conducted to reveal the response on regrowth and grain yield of winter wheat plants to clipping treatment. Two winter wheat (Triticum aestivum) cultivars, Longyu 4 (LY) and Yunhan 2 (YH), were used, and clipping was done at the tillering stage, with cutting treatments to 6 cm in height (R6), to 3 cm in height (R3), and no-cut as control (CK). The results showed that the leaf area index and net photosynthesis rate of the two cultivars at the anthesis stage after clipping recovered to control levels, the aboveground biomass and root biomass of LY under R6 and R3 decreased by 23% and 3% (P>0.05), and 12% and 13% (P>0.05) in comparison with CK, respectively. The aboveground biomass of YH decreased by 22% and 15% (P>0.05) compared with its control under R6 and R3, however, root biomass under R3 was equal to its control. Clipping caused the proportion of aboveground biomass in the whole plant to decline, and ratios of stem to leaf in aboveground parts decreased and increased, respectively. There was no difference in biomass allocation patterns aboveground or below ground between R6 and CK; However, a higher proportion of dry matter transferred to aboveground under R3 than that under CK, implying that suitable cutting disturbance may release growth redundancy through the source-sink coordination to maintain grain yield formation.