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Background Cell wall architecture plays a key role in stalk strength and forage digestibility. Lignin, cellulose and hemicellulose are the three main components of the plant cell wall and can impact stalk quality by affecting cell wall structure and strength. To explore cell wall development during secondary cell wall lignification in maize stalks, conventional and conditional genetic mappings was used to identify the dynamic quantitative trait locus (QTL) for cell wall components and digestibility traits in five growth stages after silking. Results Acid detergent lignin (ADL), cellulose (CEL), Acid detergent fiber (ADF), neutral detergent fiber (NDF), and in vitro dry matter digestibility (IVDMD) of stalk were evaluated in a maize recombinant inbred line (RIL) population. The cell wall components gradually increased in the 10–40 days after silking (DAS), reached a maximum at 30–40 DAS, and then steadily decreased. IVDMD decreased over the initial 40 DAS and then increased slightly. Seventy-two QTL were identified for five traits and each accounted for 3.48–24.04% of the phenotypic resistance variation. Twenty-six conditional QTL were detected using conditional QTL mapping. 22 out of 24 conditional QTL were found for stages III|II and V|IV. Six QTL hotspots were found localized in bins 1.08, 2.04, 2.07, 7.03, 8.05, and 9.03 in the maize genome. Conclusion The unconditional pleiotropic QTL in bins 1.08 and 8.05 were also associated with stalk strength. Furthermore, several pleiotropic QTL for cell wall and digestibility were found not associated with stalk strength. A simultaneous improvement in forage digestibility and lodging resistance can be achieved by pyramiding multiple effective QTL identified in the present study. |
