Cell wall composition and biomass digestibility diversity in Mexicanmaize (Zea mays L) landraces and CIMMYT inbred lines

摘要

Maize is one of the most important crops worldwide. Historically, breeding efforts in this crop have been primarilyfocused on the improvement of grain yield and stability and just recently also on the potential utility of maize stover(above ground biomass excluding the grain) as a source of biomass for the production of feed, fiber and cellulosicethanol. The International Maize and Wheat Improvement Center (CIMMYT) holds one of the largest maize germplasmcollections in the world and therefore is an important source of phenotypic and genetic diversity for manytraits. Our objectives were to assess the phenotypic diversity for cell wall composition and biomass digestibilityin Mexican tropical, subtropical and highland maize landraces and elite maize lines (CMLs) in the CIMMYT germplasmcollection, as well as to evaluate the relationship between place of origin of these materials and phenotypicexpression of biomass compositional traits. The range of variation for neutral detergent fiber for three groups oflandraces was from 47 to 73%. Slightly larger levels of phenotypic variation were observed for this trait in the setof CMLs evaluated (42 to 78%). Some of the inbred lines, such as CML 507, presented superior characteristicsin terms of cell wall composition and digestibility. The Tuxpeno tropical-subtropical race, widely used in CIMMYTbreeding programs, formed a cluster characterized by high cell wall content and low biomass digestibility. TheCIMMYT germplasm collection appears to be a vast source of untapped genetic and phenotypic variation for theimprovement of maize biomass composition.