Abstract: Nucleotide sequences encoding YEP6 polypeptides are provided herein, along with plants and cells having reduced levels of YEP6 gene expression, reduced levels of YEP6 polypeptide activity, or both. Plants with reduced levels of gene expression of at least one YEP6 gene and/or reduced levels of YEP6 polypeptide activity that exhibit increased yield, increased staygreen, increased abiotic stress tolerance, or any combination of these, are provided. Methods for increasing yield, staygreen and abiotic stress tolerance in plants, by modulating YEP6 gene expression or activity, are also provided.