Germination and Fresh Leaf Yield of Amaranthus Species Grown With or Without a Pesticide Seed Treatment

Application of pesticides to amaranth seed can provide a mode of action to manage specific insect pests and seedborne pathogens and improve yield, depending on cultivar and a pesticide’s active ingredients. The impact of two commercially available seed treatments on germination and leaf yield of eight advanced lines and a local cultivar, represented in four Amaranthus species ( Amaranthus blitum L., Amaranthus hybridus L., Amaranthus dubius Mart. Ex Thell., and Amaranthus hypochondriacus L.) cultivated in Kenya were evaluated. Seeds of each line were treated with either a commercial formulation of Apron Star™ (thiamethoxam 20 g/kg + metalaxyl-M 20 g/kg + difenoconazole, 2 g/kg) or Monceren™ (imidacloprid 233 g/L + pencycuron 50 g/L + thiram, 107 g/L) or remained untreated as a control. The effect of these treatments was determined 1 day after application and after 3 months of storage, a storage time often used by subsistence farmers in Kenya. Seeds were stored in a seed storeroom 25 ± 1 °C, 60% to 70% relative humidity (RH), and a 12-hour light/12-hour dark photoperiod. A higher percentage of germination, 61.6% was observed for seeds of the A. blitum line treated with Apron Star and a lower percentage of 1.5% occurred with untreated seed of A. dubius line. Significant interactions of line or cultivar with seed pesticide application and line or cultivar with storage time were observed for fresh leaf weight, and pesticide application or storage time did not provide consistent increases in yield across lines or cultivar. The highest fresh leaf weights occurred with ‘Terere’, which was similar to lines of A. hybridus . Under high tunnel conditions, plants from amaranth seeds treated with either pesticide had higher leaf production than untreated seeds, and plants from seeds stored 1 day after Apron Star application and 3 months after Monceren application were higher than untreated seed stored for one day or 3 months.