A reaction norm for flowering time plasticity reveals physiological footprints of maize adaptation

Understanding how plant phenotypes are shaped by their environments is crucial for addressing questions about crop adaptation to new environments. This study investigated the interplay between developmental responses to temperature fluctuations and photoperiod perception in maize that contribute to genotype-by-environment variation in flowering time. We present a physiological reaction norm for flowering time plasticity (PRN-FTP) for studying large collections of genotypes tested in multi-environment trial (MET) networks. Using a new variable for computational envirotyping of sensed photoperiod, it was found that, at high latitudes, different genotypes in the same environment can experience hours-long differences in photoperiod. This emphasizes the importance of considering genotype-specific differences in the experienced environment when investigating plasticity. A statistical framework is introduced for modeling the PRN-FTP as a non-linear response function, with parameters putativel..., Multiple experiments and datasets from different projects were assembled to: (D1) select a temperature response function for thermal time estimation; (D2) estimate the thermal time duration between crop emergence and tassel initiation (Ttem-ti) for diverse maize lines; (D3) envirotype sensed photoperiod (DLs) in maize fields across the Northern Hemisphere; (D4) demonstrate methods for modeling a physiological reaction norm for flowering time plasticity (PRN-FTP); and (D5) compare the trait space of parameters estimated from the PRN-FTP in a diversity panel constituting separate breeding pools of maize. The current study focuses on days to anthesis (male flowering) as the final characteristic.
(D1) Three temperature response functions (Methods S1, Eq. S1-S3; see Supplemental Information of the Main text) for measuring thermal time were compared using a dataset with 19 hybrids tested in at least 34 field environments, spanning latitudes from 30.5371°N to 51.5016°N (File S1; data sourced f..., , # Data from: A reaction norm for flowering time plasticity reveals physiological footprints of maize adaptation

[https://doi.org/10.5061/dryad.x95x69pth](https://doi.org/10.5061/dryad.x95x69pth)

## Description of the data and file structures

### File\_S1. Estimates of thermal time from planting to male flowering (anthesis) for Genomes-To-Fields data used to compare temperature response functions.

Dataset D1: Contains metadata and best linear unbiased estimates (BLUEs) for days to anthesis (DTA) of 19 hybrids in at least 34 field environments. Field metadata and BLUEs for DTA were assembled from McFarland et al (2020) and Rogers et al. (2021) (see Main text). Three temperature response functions (Eq. S1-S3, Methods S1 of Main text) were used to estimate thermal times.

File_S1.txt (tab delimited); description of columns
env: environment code (year x location)
year: year of planting
lat: latitude of field environment
lon: longitude of field environment
hybrid: hybrid name (19 in tota...