The specification provides methods of obtaining a genetically modified plant which has increased production potential compared to a control plant, the method comprising the steps of i) obtaining a plurality of plants at least one of which comprises in its genome a heterologous polynucleotide, ii) identifying from the plurality of plants a plant which has increased production potential relative to the control plant and comprises the heterologous polynucleotide, and iii) selecting the genetically modified plant, wherein the polynucleotide comprises a transcriptional control sequence operably linked to a nucleic acid sequence which encodes an agent that modifies endogenous starch phosphorylation and/or starch degradation in the plant. In some embodiments, the plant has increased endogenous glycosylase or increased digestibility compared to a control plant. In some specific embodiments, the endogenous starch phosphorylation and/or starch degradation is modified by modifying expression or activity of one or more enzymes selected from the group consisting of &alpha-amylase (EC 3.2.1.1), &bgr-amylase (EC 3.2.1.2), glucoamylase (EC 3.2.1.3), starch phosphorylase (EC2.4.1.1), glycosylase (EC 3.1.33), sucrase-isomaltase (EC 3.2.10), amylomaltase (EC 2.4.1.25), maltase (EC 3.2.1.20), isoamylase, and &alpha-glucan, water dikinase (GWD, EC 2.7.9.4).
