#$%^&*AU2016200894A120160310.pdf#####ABSTRACT The present invention relates to genetic engineering methods and materials for improving plant yields. The present invention discloses that upregulating EXPA1 gene expression or activity of EXPA1 polypeptide, or co-expression of GhRDL1 and GhEXPA1 gene can improve plant traits. These methods have applications in crops and flower productions.