Compositions and methods for improving crop yields through trait stacking

A method for producing a transgenic corn plant, the method comprising:

• (I) crossing a first transgenic corn plant with a second transgenic corn plant, wherein the first transgenic corn plant comprises a first recombinant expression cassette comprising a first heterologous plant-expressible promoter operably linked to a transcribable DNA sequence encoding a non-coding RNA for suppression of one or more gibberellic acid 20 (GA20) oxidase genes, wherein the non-coding RNA comprises a targeting sequence that is (a) at least 95% complementary to at least 19 consecutive nucleotides of a first mRNA molecule encoding a first endogenous GA20 oxidase protein that has at least 95% amino acid sequence identity to the amino acid sequence as set forth in SEQ ID NO:
• 9, and 2) (b) at least 95% complementary to at least 19 consecutive nucleotides of a second mRNA molecule encoding a second endogenous GA20 oxidase protein that has at least 95% amino acid sequence identity to the amino acid sequence as set forth in SEQ ID NO:
• 15, and wherein the expression of one or more endogenous GA20 oxidase genes is reduced in the first transgenic corn plant as compared to a control wild-type corn plant grown under comparable conditions, and wherein the second transgenic corn plant comprises a second recombinant expression cassette comprising a DNA sequence encoding a CONSTANS-like (COL) polypeptide that has at least 95% amino acid sequence identity to the amino acid sequence as set forth in SEQ ID NO:
• 168;
• and
• (II) producing a transgenic progeny corn plant comprising the first and second recombinant expression cassettes and that has the reduced expression of the one or more endogenous GA20 oxidase genes, and increased expression of said CONSTANS-like (COL) polypeptide as compared to a control wild-type corn plant grown under comparable conditions, and wherein expression of said non-coding RNA and said CONSTANS-like (COL) polypeptide in said transgenic progeny corn plant results in a semi-dwarf phenotype, and an increase in one or more improved ear trait selected from the group consisting of ear area, ear volume, ear diameter, ear length, kernels per ear, single kernel weight, yield, grain yield estimate, broad acreage yield, and ear fresh weight as compared to a control wild-type corn plant grown under comparable conditions.