The genetic architecture of maize height

Area of Science:

• Plant genetics and breeding
• Quantitative trait locus (QTL) mapping
• Genomic prediction

Background:

• Maize (Zea mays L.) plant height is a highly heritable and easily measurable trait.
• Identifying genetic variants controlling natural variation in maize height presents a significant challenge.
• Previous studies highlight the complexity of maize height genetics.

Purpose of the Study:

• To map quantitative trait loci (QTL) and identify alleles influencing natural variation in maize plant height.
• To compare the efficacy of different genetic mapping and prediction methodologies.
• To elucidate the genetic architecture underlying maize height.

Main Methods:

• Phenotypic data collection for plant height, ear height, flowering time, and node counts across 13 environments for over 7300 maize inbred lines.
• Application of joint-linkage mapping, fine mapping in near-isogenic lines (NILs), genome-wide association studies (GWAS), and genomic best linear unbiased prediction (GBLUP).
• Heritability estimation and assessment of prediction accuracy for different models.

Main Results:

• Maize height heritability was estimated to be over 90%, indicating strong genetic control.
• Family-nested QTL mapping identified loci explaining up to 2.1 ± 0.9% of height variation, with two tropical alleles validated.
• GWAS revealed associations with known height loci (e.g., brassinosteroid-deficient dwarf1).
• GBLUP models explained over 80% of height variation and demonstrated higher prediction accuracy than QTL-based models.

Conclusions:

• Maize height exhibits a highly polygenic genetic architecture under strong genetic control.
• Multiple genetic models can explain height variation, but GBLUP shows superior predictive performance.
• This study provides valuable insights into the genetic basis of maize height and enhances prediction capabilities.