Mapping dynamic QTL of stalk sugar content at different growth stages in maize
2015
Bian, Yunlong | Gu, Xiao | Sun, Donglei | Wang, Yijun | Yin, Zhitong | Deng, Dexiang | Wang, Yanqiu | Li, Guosheng
The stalk sugar content in silage maize plays an important role in improving its forage quality and palatability. In this study, we reported a dynamic quantitative trait loci (QTL) analysis of stalk sugar content at different growth stages in maize. A recombinant inbred line (RIL) population with 202 lines derived from a cross of YXD053 × Y6-1 was used to identify the dynamic QTL for stalk sugar content (Brix) in maize. The Brix of RILs were measured at four stages in two environments. Twenty-two QTLs affecting maize stalk sugar content (Brix) were detected by unconditional mapping method. Fifteen QTLs were identified using conditional mapping approach. No QTL was detected at all sampling stages. Six QTL, qSSC-2.1, qSSC-2.2, qSSC-2.3, qSSC-5.1, qSSC-9.1 and qSSC-9.4, were detected by both unconditional and conditional mapping. One major QTL qSSC-2.1 flanked by markers bnlg1909 and umc1635 on chromosome 2 had a relatively high net effects of gene expression from anthesis stage to 20 days after anthesis. A total of six pairs of QTL with significant epistatic effects were identified at different developmental stages. No significant QTL × environment interactions were observed. Stalk sugar content is controlled by a complex genetic mechanism, and the QTL detected at different development stages might be important contributors to stalk sugar content in maize.
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