Effect of Valencia Peanut Seed Treatments on Germination, Vigor, and Soilborne Diseases.

Peanut (Arachis hypogaea L.) is an economically important crop both in New Mexico and in southeastern United States. In New Mexico, the Valencia peanut (A. hypogaea subsp. fastigata var fastigata) market type is primarily grown. Several soilborne fungal pathogens including Rhizoctonia solani, Sclerotinia sclerotiorum, and Sclerotiorum rolfsii constitute major constraints to Valencia peanut production (Sanogo and Puppala, 2007 and 2012). Soilborne disease pressures continuously drive the need to improve existing management schemes or to explore new ones. This study was conducted to evaluate the effects of three seed treatments; Dynasty (Azoxystobin), EndoFine SI (Clonostachys rosea), and Rancona Xxtra (Ipconazole/Metalaxyl) on Valencia peanut germination, vigor and against soilborne diseases. For each treatment, one kilogram of Valencia seed was mixed with Dynasty, EndoFine SI, or Rancona Xxtra at a rate of 0.28 kg/ha, 0.14 kg/ha and 0.28 kg/ha respectively. One kilogram of untreated seed was used as a control. Seeds were hand planted at a 5-cm depth on a commercial farm in Lingo, New Mexico. Plots were arranged in a randomized complete block design with 4 replications per treatment. Plots were assessed for percent germination, plant vigor, pod yield, total sound mature kernel (%), 100-seed weight, and disease incidence. A complementary study was conducted under controlled environment conditions by using the same treated Valencia seeds. A soil/sand mixture was sterilized twice in an autoclave, and then infested with oat kernels colonized with Sclerotiorum rolfsii at the rate of 10% (weight basis). Seed germination and plant growth were assessed. Results from the field study showed no statistical difference among seed treatments in regards to any of the variables measured. In contrast, results from the controlled environment study showed a statistical difference in seed germination and plant growth when peanut seeds were treated with Rancona Xxtra and Dynasty compared to seeds untreated and treated with Endofine.