“…Other strategies such as flow cytometry (Couto et al 2013, Baleroni et al, 2021, chromosome counts (Sekiya et al 2020), and molecular markers (Ribeiro et al 2018) can be used, but are less efficient, expensive and laborious. Therefore, the use of morphological traits of seedlings and plants (Chaikam et al 2017), such as first-leaf-sheath color (Sekiya et al 2020) associated with stomatal guard cell length or area (Choe et al 2012, Ribeiro et al 2022, are important alternatives for haploid identification in corn. The green first-leaf-sheath is a recessive characteristic and can be observed in some corn genotypes, such as the supersweet genotypes studied by Sekiya et al (2020), which allows 100% accuracy in the early haploid seedling selection, as the diploid inducers and F1's have a purple first-leaf-sheath.…”