The Impact of Genotype × Environment Effects on Runner‐Type Peanut Seed Vigor Response to Temperature

Abstract

Experiments conducted from 2007 to 2012 evaluated the genotype × environment effects on breeder seed of eight peanut (Arachis hypogaea L.) cultivars grown under similar production practices. Seed germination and vigor by plot replication were evaluated in Petri‐dishes incubated over a thermal gradient ranging from 12 to 36°C at approximately 1.0°C increments. Growing degree day (GDD) accumulation for each temperature increment was calculated based on daily mean temperature measured by thermocouples. Lorentzian distribution models were used to establish the temperature and time (hours) to maximum germination. With respect to maximum germination and temperature; Georgia‐07W (23.9°C) < Florida‐07 (25.0°C) < Georgia Greener (25.2°C) < Georgia‐06G (25.3°C) = Tifguard < Georgia Green (26.4°C) < Georgia‐09B (27.1°C) = Georgia‐02C. Nonlinear regression indices from logistic growth curves with three parameters were used to elucidate seed germination by cultivar. These data included maximum indices of germination for each cultivar by year establishing parameter estimates using nonlinear regression, GDD value at 80% germination (Germ80), and temperature required by each cultivar for optimum germination. Peanut cultivar vigor varied by year with respect to overall GDDs to reach Germ80 and maximum germination (b0). Ranking of cultivars by GDD to reach Germ80 were: Georgia Green < Georgia‐02C < Georgia‐06G = Georgia Greener < Georgia‐09B < Georgia‐07W < Tifguard < Florida‐07. This indicates that Georgia Green had much greater vigor than Florida‐07 over the course of the experiments. Georgia‐06G peanut seed were consistent with respect to germination, Germ80, and b0. All cultivars exhibited phenotypic variation by year, with genotype consistency across years.Core Ideas Peanut cultivars evaluated exhibited phenotypic vigor variation by year, with genotypic stability across years. This form of evaluation provided an indication of vigor which may assist breeders in determining the success of the cultivar over a range of temperatures. Larger seeded peanut cultivars exhibited less vigor than smaller seeded cultivars.