Fine mapping of qKRN8 , a QTL for maize kernel row number, and prediction of the candidate gene
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ORIGINAL ARTICLE
Fine mapping of qKRN8, a QTL for maize kernel row number, and prediction of the candidate gene Xuesong Han1 · Yao Qin1 · Ada Menie Nelly Sandrine1 · Fazhan Qiu1 Received: 9 August 2019 / Accepted: 3 August 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Key message qKRN8, a major QTL for kernel row number in maize, was fine mapped to an interval of ~ 520 kb on chromosome 8 and the key candidate gene was identified via expression analysis. Abstract Kernel row number (KRN) is one of the most important yield-influencing traits and is closely associated with female inflorescence development in maize (Zea mays L.). In this study, an F2:3 population derived from a cross between V54 (low KRN line) and Lian87 (high KRN line) was used to map quantitative trait loci (QTLs) conferring KRN in maize. We identified 12 QTLs for KRN in four environments, each explaining 1.40–14.95% of phenotypic variance. Among these, one novel major QTL (named qKRN8) was mapped to bin 8.03 in all four environments, explaining 8.79–14.95% of phenotypic variation. By combining map-based cloning with progeny testing of recombinants, we ultimately mapped qKRN8 to an ~ 520 kb genomic interval, harboring six putative candidate genes. Among them, one candidate gene showed contrasted expression level in immature ears of the near-isogenic lines qKRN8Lian87 and qKRN8V54. These findings should facilitate molecular breeding for KRN and the further identification of the polymorphism underlying this QTL.
Introduction Maize (Zea mays L.) is one of the most important cereal and forage crops worldwide. Improving maize yield is a major goal of breeders to ensure food security. Maize yield is based mainly on effective ear number, kernel number per ear, and kernel weight. Kernel number per ear can be further classified into kernel number per row and kernel row number (KRN). Thus, KRN is an important yield component in maize that directly affects grain yield. KRN is also closely associated with female inflorescence development.
Communicated by Laurence Moreau. Xuesong Han and Yao Qin have contributed equally to this work. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00122-020-03660-7) contains supplementary material, which is available to authorized users. * Fazhan Qiu [email protected] 1
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, No. 1, Shizishan Street, Hongshan District, Wuhan 430070, People’s Republic of China
The transformation of axillary meristems (AMs) into ear inflorescence meristems (IMs) marks the initiation of female inflorescence development. The IM is indeterminate and committed to form a spikelet pair meristem (SPM). Each SPM gives rise to two spikelet meristems (SMs), and each SM forms two floral meristems (FMs): the upper FM, which forms a kernel after fertilization, and the lower FM, which ultimately undergoes floral organ degeneration. The number of SPMs on the female inflorescence meris
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