The present disclosure discloses the use of gene encoding gibberellin 3β-hydroxylase of G. max, GmGA3ox1. The use of gibberellin 3β-hydroxylase gene of G. max, GmGA3ox1, set forth in SEQ ID NO:1, in genetic engineering of seed weight of Arabidopsis thaliana and Glycine max. In A. thaliana, overexpression of GmGA3ox1 can complement the low seed weight phenotype of atga3ox1 mutant. In G. max, overexpression of the excellent haplotype of the gene can significantly improve the seed weight of G. max.

The present disclosure provides modified, transgenic, or genome edited/mutated corn plants that are semi-dwarf and have one or more improved ear traits and yield relative to a control plant, such as increased ear area, increased ear volume, increased single kernel weight, increased ear fresh weight, increased ear diameter, increased ear length, increased yield, increased kernels per ear, decreased ear tip void, and decreased ear void. The modified, transgenic, or genome edited/mutated corn plants comprise a transgene encoding one or more CONSTANS (CO) or CONSTANS-like (COL) polypeptides and a transgene encoding one or more MADS-box polypeptides, and can also have a reduced expression of one or more GA20 or GA3 oxidase genes. Also provided are methods for producing the modified, transgenic, or genome edited/mutated corn plants.

A maize plant or maize plant part, and methods of making and using the same, are provided herein, wherein the maize plant or maize plant part comprises a mutant allele of an endogenous brachytic 2 (Z?r2) gene, a mutant allele of an endogenous GA20 oxidase or GA3 oxidase gene, or a transgene encoding a non-coding RNA molecule that targets an endogenous GA oxidase gene for suppression, and/or a mutant allele of an endogenous brown midrib 3 (bin3) gene. The maize plants or maize plant parts may be homozygous or heterozygous for the transgene or the mutant alleles. Additionally, the maize plant or maize plant part may be part of a silage product, where the harvest product is formed by harvesting an above-ground biomass of a population of the maize plants or a population of intercropped silage plants including such maize plants and making a silage product from the above-ground biomass.

The present disclosure provides compositions and methods for altering gibberellin (GA) content in corn or other cereal plants. Methods and compositions are also provided for altering the expression of genes related to gibberellin biosynthesis through suppression, mutagenesis and/or editing of specific subtypes of GA20 or GA3 oxidase genes. Modified plant cells and plants having a suppression element or mutation reducing the expression or activity of a GA oxidase gene are further provided comprising reduced gibberellin levels and improved characteristics, such as reduced plant height and increased lodging resistance, but without off-types.

Provided is a use of gene encoding gibberellin 3B-hydroxylase of G. max, GmGA3ox1. The use of gibberellin 3-hydroxylase gene of G. max, GmGA30x1, set forth in SEQ ID NO:1, is in genetic engineering of seed weight of Arabidopsis thaliana and Glycine max. In A. thaliana, overexpression of GmGA3ox1 can complement the low seed weight phenotype of an atga3ox1 mutant. In G. max, overexpression of the excellent haplotype of the gene can significantly improve the seed weight of G. max.