Validation of functional polymorphisms affecting maize plant height by unoccupied aerial systems discovers novel temporal phenotypes.

Abstract

Plant height (PHT) in maize (Zea mays L.) has been scrutinized genetically and phenotypically due to relationship with other agronomically valuable traits (e.g., yield). Heritable variation of PHT is determined by many discovered quantitative trait loci; however, phenotypic effects of such loci often lack validation across environments and genetic backgrounds, especially in the hybrid state grown by farmers rather than the inbred state more often used by geneticists. A previous genome-wide association study using a topcrossed hybrid diversity panel identified two novel quantitative trait variants controlling both PHT and grain yield. Here, heterogeneous inbred families demonstrated that these two loci, characterized by two single nucleotide polymorphisms (SNPs), cause phenotypic variation in inbred lines, but that size of these effects were variable across four different genetic backgrounds, ranging from 1 to 10 cm. Weekly unoccupied aerial system flights demonstrated the two SNPs had larger effects, varying from 10 to 25 cm, in early growth while effects decreased toward the end of the season. These results show that allelic effect sizes of economically valuable loci are both dynamic in temporal growth and dynamic across genetic backgrounds, resulting in informative phenotypic variability overlooked following traditional phenotyping methods. Public genotyping data show recent favorable allele selection in elite temperate germplasm with little change across tropical backgrounds. As these loci remain rarer in tropical germplasm, with effects most visible early in growth, they are useful for breeding and selection to expand the genetic basis of maize.

Plant phenotyping relevance

UASを用いた週次測定により、従来法では見落とされるトウモロコシ草丈の時間変動を抽出し、遺伝子効果を検証しており、フェノタイピング手法の適用が研究上の中心的役割を果たしている。

Code and data availability

The paper's Data Availability statement deposits its own UAS point cloud data, orthomosaic tif files, processing reports, ruler-based plant height measurements, UAV-derived canopy height measurements, field map, and experimental area files on figshare, plus supplementary material on the G3 figshare repository. Theseare