3.1. Coordinated growth responses
The rates of seed germination, leaf appearance, tillering or branching and leaf expansion show coordinated responses to warm temperature in crops (Parent & Tardieu, 2012), but with large variation among different cultivars from the same species (Bahuguna et al., 2014; Friend, 1965; Li, Kennedy, Huybrechts, Dochy, & Geuten, 2019). High temperature delays the start of stem elongation and results in faster stem growth rates, but without modifying total time to heading in wheat and barley (BorrĂ s-Gelonch, Denti, B Thomas, & Romagosa, 2011; Karsai et al., 2013; Kiss et al., 2017). However, a temperature above the optimum decreases the number of leaves and tillers, as well as final stem height (Dixon et al., 2019; Hemming et al., 2012; Karsai et al., 2013). Some species, however, react differently to elevated ambient temperatures during vegetative growth. For example, soybean does not exhibit big changes during vegetative development at higher temperatures (Choi, Ban, Seo, Lee, & Lee, 2016; Lippmann et al., 2019).