Quantitative trait loci for cell-wall components in recombinant inbred lines of maize (Zea mays L.) I: stalk tissue

Abstract

Maize silage is a significant energy source for animal production operations, and the efficiency of the conversion of forage into animal mass is an important consideration when selecting cultivars for use as feed. Fiber and lignin are negatively correlated with digestibility of feed, so the development of forage with reduced levels of these cell-wall components (CWCs) is desirable. While variability for fiber and lignin is present in maize germplasm, traditional selection has focused on the yield of the ear rather than the forage quality of the whole plant, and little information is available concerning the genetics of fiber and lignin. The objectives of this study were to map quantitative trait loci (QTLs) for fiber and lignin in the maize stalk and compare them with QTLs from other populations. Stalk samples were harvested from 191 recombinant inbred lines (RILs) of B73 (an inbred line with low-to-intermediate levels of CWCs) x De811 (an inbred line with high levels of CWCs) at two locations in 1998 and one in 1999 and assayed for neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL). The QTLs were detected on nine chromosomes, mostly clustered in concordance with the high genetic correlations between NDF and ADF. Adjustment of NDF for ADF and ADF for ADL revealed that most of the variability for CWCs in this population is in ADF. Many of the QTLs detected in this study have also been detected in other populations, and several are linked to candidate genes for cellulose or starch biosynthesis. The genetic information obtained in this study should be useful to breeding efforts aimed at improving the quality of maize silage.

Genetic Variation in Biomass Traits among 20 Diverse Rice Varieties

“…This suggests that the compositions of leaf and stem structural carbohydrates are under separate genetic control, and, based on complementary studies with maize and sorghum (Sorghum bicolor), this may be a common characteristic in monocots (Krakowsky et al, 2005(Krakowsky et al, , 2006Murray et al, 2008). Like sorghum (Murray et al, 2008), most of the OryzaSNP varieties (17 out of 20) contain more biomass in their stems than in leaves.…”

Non-parental banding patterns in recombinant inbred line population of maize with SSR markers

“…They suggested that this band was generated by annealing of complementary random-amplified polymorphic DNA alleles. However, Krakowsky et al (2005), who worked with restriction fragment length polymorphism (RFLP) markers, hypothesized that the reasons underlying non-parental banding patterns in RILs may be related to contamination during inbreeding, the use of parental lines that were still segregating at some alleles, or incomplete digestion of DNA during RFLP analysis. Casa et al (2000) suggested that non-parental fragments may be derived from residual heterozygosity, genomic rearrangements, or loss of parental variation over generations of inbreeding and mutation.…”

Comparative mapping of fiber, protein, and mineral content QTLs in two interspecific Leymus wildrye full-sib families

“…The NDF fraction includes cellulose, lignin, and hemicellulose; whereas the ADF fraction is composed mainly of cellulose and lignin without hemicellulose (Van Soest 1994). The genetic control of ADF and/or NDF content has been examined by QTL analysis in perennial ryegrass (Cogan et al 2005), maize (Krakowsky et al 2005(Krakowsky et al , 2006Lübberstedt et al 1997;Méchin et al 2001) and Arabidopsis (Barrière et al 2005). Crude protein and mineral content receive less attention by forage grass breeders, in part because soil fertility can have relatively large effect on these traits, because protein and mineral supplements are commonly used, and also because crude protein is often negatively correlated with yield (Casler and Vogel 1999;Casler 2001).…”