Characterization of quantitative trait loci affecting fiber and lignin in maize (Zea mays L.)

Maize stover is an important component of whole plant silage, and fiber and lignin (i.e., cell wall components (CWCs)) in stover are negatively correlated with digestibility. The objectives of this study were to map and characterize quantitative trait loci (QTL) for neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) in the sheath and stalk of maize. The tissues were analyzed separately due to potential heterogeneity for CWCs among tissues in the stover. Inbred DE811 (high levels of CWCs) was crossed to inbred B73 (low-intermediate levels) to produce a population of 147 F-3 lines from which tissue samples were harvested from two locations in 1989 and analyzed for CWCs. The F-3 lines also were genotyped at 88 restriction fragment length polymorphism (RFLP) loci to facilitate QTL mapping with composite interval mapping (CIM). Ten QTL each for sheath NDF and ADF were detected on chromosomes 1, 3, 4, 7, 8, 9, and 10 and were associated with 55 and 62% of the phenotypic variation, respectively. Eleven, twelve and ten QTL for stalk NDF, ADF, and ADL associated with 69, 71, and 62% of the phenotypic variation, respectively, were detected on chromosomes 1, 2, 3, 4, 6, 7, 8, and 9. The QTL for NDF in the sheath and stalk were all within 20 cM of QTL for ADF in the respective tissues, though tissue specific QTL clusters were observed, all in concordance with the previously reported genetic correlations for these traits. The majority of the QTL for NDF and ADF were linked to candidate genes involved in carbohydrate metabolism, while two of the QTL for stalk ADL were linked to candidate genes for lignin biosynthesis.