Abstract: In total, 244 varieties and advanced lines from four Chinese winter wheat regions were used to investigate the variation of kernel hardness, flour particle size, puroindoline type and solvent retention capacity. The results indicated that five puroindoline alleles including Pina-D1a/Pinb-D1a (wild type), Pina-D1b/ Pinb-D1a, Pina-D1a/Pinb-D1b, Pina-D1a/Pinb-D1d and Pina-D1a/Pinb-D1p were observed in Chinese winter wheats, and Pina-D1a/Pinb-D1b was the most prevalent type with a frequency of 81.2% in hard wheats. Pina-D1a/Pinb-D1p was only present in Chinese wheats up to now. Significant correlations were observed between kernel hardness and four kinds of SRC (solvent retention capacity) and the coefficients of correlation between WSRC (water solvent retention capacity) and hardness by SKCS (single kernel characterization system) and NIR (near infrared spectroscpy) were 0.73 and 0.64, respectively. Means of WSRC and SCSRC (sodium carbonate solvent retention capacity) in varieties with Pina-D1b/Pinb-D1a allele were significantly higher than that of Pina-D1a/Pinb-D1b. In addition, wheats in different regions have different hardness types and solvent retention capacity. The average of WSRC in Northern China Plain winter wheats was significantly different from that of Southwestern winter wheat region, and the average of SCSRC in Northern China Plain winter wheats was significantly different from that of the middle and lower reaches of the Yangtze River winter wheat region. This study has provided useful information for improving Chinese wheat hardness and in the application of solvent retention capacity at early generation selection in wheat breeding program.

Key words: Common wheat (Triticum aestivum Linn.), Puroindoline alleles, Solvent retention capacity, Kernel hardness, Processing quality