b'stem elongation or tuber initiation, manipulate stem number, or influ-encetubershape.Whenapplica-tions are too high, this can lead to undesiredresultssuchasover-growth,toomanytubersoreven plantinjuryordeath.Herbicides suchas2,4-Dordicambaactasa plant growth hormone. These her-bicides used at extremely low rates can manipulate plant growth, but at higherdosestheycancauseplant death. The reason they work as her-Figure 2. Effect of plant growth regulator treatments on Sangre and Dark Red bicidesisbecausetheyremainNorland yield. activeintheplantmuchlonger than natural hormones. Theabilitytomakeslightadjust-ments in potato plants can be valu-able for seed, fresh, chip and process growers to increase or decrease stem number, tuber set and tuber size or toelongatetubersforfryyield. However,theuseofthesecom-poundshasbeenfrustratingfor many because of a number of rea-sons.InconsistentapplicationrateFigure 3. Effect of plant growth regulator treatments on Dakota Russet and Bannock Russet yield. andvaryingvarietalresponsescan leadtoundesiredresults.Thereis notaonesizefitsallforplant growth regulators in potato produc-tion. All plant growth regulators act differentlywithintheplantand responses vary based on cultivar or physiological seed age. Howcanyousolvethismystery? One of the first things you may con- Figure 4. Length to width ratio of Dakota russet following plant growth regu-lator treatments.sider doing is starting with a consis-tent application method since thesetors as a seed treatment. That way,basedonnozzleangle,soilmois-growthregulatorsaresopotent.we could apply a specific amount ofture, or how much a seed tuber may What we have done in our researchactive ingredient on a ton of seed.roll, among other factors at plant-studies is apply plant growth regula- In-furrowapplicationscanvarying. It is not practical to dip large APRIL 2022 POTATO GROWER 13'