genetic architecture of leaf number and its genetic relationship to flowering time in maize

• Published in: The New phytologist 2016-04, Vol.210 (1), p.256-268
• Main Authors: Li, Dan, Wang, Xufeng, Zhang, Xiangbo, Chen, Qiuyue, Xu, Guanghui, Xu, Dingyi, Wang, Chenglong, Liang, Yameng, Wu, Lishuan, Huang, Cheng, Tian, Jinge, Wu, Yaoyao, Tian, Feng
• Format: Article
• Language: English
• Subjects: corn; Crosses, Genetic; domestication; flowering; flowering time; Flowers - genetics; Flowers - physiology; genes; Genetic Association Studies; genetic markers; genetic overlap; genetic relationships; inbred lines; Inbreeding; leaf number; leaves; loci; maize (Zea mays); phenology; Phenotype; Physical Chromosome Mapping; plant architecture; Plant Leaves - anatomy & histology; Plant Leaves - genetics; pleiotropy; Quantitative Trait Loci - genetics; quantitative trait locus (QTL); Reproducibility of Results; single nucleotide polymorphism; Time Factors; Zea mays; Zea mays - genetics; Zea mays - physiology
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.13765

The number of leaves and their distributions on plants are critical factors determining plant architecture in maize (Zea mays), and leaf number is frequently used as a measure of flowering time, a trait that is key to local environmental adaptation. Here, using a large set of 866 maize‐teosinte BC₂S₃ recombinant inbred lines genotyped by using 19 838 single nucleotide polymorphism markers, we conducted a comprehensive genetic dissection to assess the genetic architecture of leaf number and its genetic relationship to flowering time. We demonstrated that the two components of total leaf number, the number of leaves above (LA) and below (LB) the primary ear, were under relatively independent genetic control and might be subject to differential directional selection during maize domestication and improvement. Furthermore, we revealed that flowering time and leaf number are commonly regulated at a moderate level. The pleiotropy of the genes ZCN8, dlf1 and ZmCCT on leaf number and flowering time were validated by near‐isogenic line analysis. Through fine mapping, qLA1‐1, a major‐effect locus that specifically affects LA, was delimited to a region with severe recombination suppression derived from teosinte. This study provides important insights into the genetic basis of traits affecting plant architecture and adaptation. The genetic independence of LA from LB enables the optimization of leaf number for ideal plant architecture breeding in maize.