Genetic analysis and QTL mapping of stalk digestibility and kernel composition in a high-oil maize mutant (Zea mays L.)

摘要

P>A high-oil maize inbred line Ce03005 derived from ethylmethane-sulphonate mutagenesis was used to study the genetic basis of stalk digestibility and kernel chemical compositions, and evaluate the genetic relationship between traits. Quantitative trait loci (QTL) mapping employed 211 lines of F-3 and F-4 generations derived from Ce03005 x B73. Nuclear magnetic resonance and near-infrared reflectance spectrometry were used to analyse the following phenotypic traits: stalk digestibility and related traits including in vitro dry matter digestibility (IVDMD), in vitro cell wall digestibility (IVNDFD), neutral detergent fibre (NDF), acid detergent fibre (ADF), water soluble carbohydrate (WSC), and kernel composition including kernel oil content (KOC), kernel protein content (KPC) and kernel starch content (KSC). Correlation analysis indicated that IVDMD, IVNDFD and WSC were significantly (P = 0.01) positively correlated with KOC, while ADF and NDF were negatively correlated with KOC. Six QTL for IVDMD, five for IVNDFD, six for NDF, eight for ADF, three for WSC, eight for KOC, seven for KPC and 10 for KSC were detected in F-3 and F-4 generations. Five major QTL (R2 > 10) of qIVDMD6, qIVNDFD6, qNDF6, qADF6, qWSC6 andOlicm6 shared the same confidence interval on chromosome 6. The results suggested that KOC may be closely related or share the same QTL for stalk quality traits, and its change may have influences to the stalk components.