A Heterochromatic Knob Reducing the Flowering Time in Maize

Abstract

Maize flowering time is an important agronomic trait, which has been associated with variations in the genome size and heterochromatic knobs content. We integrated three steps to show this association. Firstly, we selected inbred lines varying for heterochromatic knob composition at specific sites in the homozygous state. Then, we produced homozygous and heterozygous hybrids for knobs. Second, we measured the genome size and flowering time for all materials. Knob composition did not affect the genome size and flowering time. Finally, we developed an association study and identified a knob marker on chromosome 9 showing the strongest association with flowering time. Indeed, modelling allele substitution and dominance effects could offer only one heterochromatic knob locus that could affect flowering time, making it earlier rather than the knob composition.

THP9 enhances seed protein content and nitrogen-use efficiency in maize

“…The total repeat content in Ames21814 was much higher than 1860 Mb in B73, due to the contribution of the Knob and CentC repeats in maize (~10.15%) (Fig. 1d and Supplementary Table 4), where previous study showed that Knobs could affect local recombination 22 . The LTR Assembly Index (LAI) score 23 (LAI=33.07) indicated the Ames21814 haplotype could be a useful reference to discover valuable alleles in the wild maize ancestoral genome.…”