Methods of extracting ribonucleic acid from plant tissue involve treating multiple groups of plant seeds with different plant growth regulators. Each group of plant seeds can be treated with a different plant growth regulator. Methods further involve germinating the plant seeds to form seedlings, harvesting tissue samples from subgroups within each group of plant seeds and seedlings at different timepoints, and extracting total RNA from each harvested tissue sample. Methods can also involve sequencing the extracted RNA, determining an expression level of a plurality of genes relative to a negative control, and identifying a subset of differentially expressed genes at each distinct timepoint.