Dissection of Leaf Angle Variation in Maize through Genetic Mapping and Meta-Analysis

Area of Science:

• Plant Genetics
• Crop Science
• Agricultural Genomics

Background:

• Maize (Zea mays L.) hybrids have evolved upright leaf angles (LAs) over 50 years, coinciding with increased yields and planting densities.
• Understanding the genetic basis of LA variation is crucial for further maize improvement.

Purpose of the Study:

• To identify and characterize quantitative trait loci (QTL) controlling leaf angle (LA) variation in maize.
• To integrate findings with previous studies through meta-analysis for a comprehensive understanding of genetic factors influencing LA.

Main Methods:

• Developed mapping populations from three diverse US maize inbred lines (B73, PHW30, Mo17).
• Genotyped populations using genotyping-by-sequencing (GBS) and phenotyped for LA across F2 and F3 generations.
• Employed inclusive composite interval mapping and a meta-analysis of 19 previous studies.

Main Results:

• Identified 12 QTL associated with LA variation, with a consistent QTL on chromosome 1 explaining 10-17% of phenotypic variance.
• Meta-analysis of 495 compiled QTL mapped to 143 genomic bins, revealing 58 bins significantly associated with LA.
• Identified 33 candidate genes within these associated genomic bins.

Conclusions:

• This study provides robust genetic evidence for QTL controlling maize LA variation across key US heterotic groups.
• The identified QTL and candidate genes offer valuable resources for future research into the molecular mechanisms of LA and for marker-assisted maize breeding.