3 and Fig. 4). Correspondingly, no significant differences were observed in histochemical staining among the four wheat genotypes; however, the area of the mechanical tissue in the solid stemmed variety was obviously larger than any of the other three genotypes (Fig. 2A to L). Lodging resistance of XNSX was 3.0- and 4.1-fold that of Line 3159 and CS, respectively. F1 plants had lower lodging resistance than XNSX, but had 2.27-fold higher values than Line 3159

(Table 1). Lodging resistance was positively correlated with WOMT (r = 1.000, P < 0.01), WOSW (r = 0.972, P < 0.05), and WOL (r = 0.986, P < 0.05) ( Table 2). In addition, significantly positive correlations were found between WOMT PFT�� in vivo and WOSW (r = 0.968, P < 0.05), WOMT and WOL (r = 0.988, P < 0.05), AOT and NOVB (r = 0.955, P < 0.05),

AOT and NSVB (r = 0.982, P < 0.05), cellulose and lignin content (r = 0.993, P < 0 .01), whereas no significant correlations were found between lodging resistance and the chemical compositions, RSW, AOVB, or AOT ( Table 2). The relationships between lodging resistance and the chemical and anatomical characteristics of the four genotypes were tested using a stepwise forward regression, where lignin, cellulose, AOT, AOVB, WOMT, WOSW, RSW and WOL were used as independent variables. Each variable was added in the order of statistical significance (P < 0.05). The best predictor of lodging resistance was obtained from a model incorporating WOMT, AOVB and WOSW as follows: LR=−20.251+0.397WOMT+5.287E−06AOVB+0.009WOSW For 607 microsatellite Seliciclib chemical structure markers, 120 showed polymorphisms between XNSX and Line 3159. Among these, Xgwm340 and Xgwm247 on chromosome 3BL exhibited amplification profiles that distinguished between the solid and hollow stemmed parents in

corresponding bulks, suggesting a possible association between stem solidness and these markers ( Fig. 5). Subsequently, the entire F2 population was genotyped for these markers. Both markers were located proximally to the solid stem locus (Xgwm340–4.0 cM–Xgwm247–12.1 cM–Solid stem QTL peak) and results from ANOVA showed that the solid stem phenotypic Interleukin-2 receptor variance explained by the Xgwm-247 locus was about 77%, and that explained by Xgwm-340 was 62%. Lodging resistance is of importance in cereal crop breeding. It is well known that morphological characteristics significantly affect lodging resistance. As a result, morphological differences among cultivars have been studied to identify morphological and anatomical traits associated with lodging response so that they could be used to breed for lodging resistance [22] and [23]. Previous studies showed that lodging resistance is negatively correlated with stem diameter [3] and [24], whereas we found that lodging resistance in the four wheat genotypes examined was positively correlated with stem wall thickness of (r = 0.972, P < 0.05). Other workers have also suggested that thicker stem walls increase lodging resistance in wheat [3] and [25].