Estimating reliability for evaluating nitrate accumulation in sorghum (Sorghum bicolor L. Moench) inbred A‐lines

Abstract

Abstract Sorghum is an important forage crop in many cropping systems. Nitrate can accumulate in the vegetative plant tissue to levels high enough that result in fatality when fed to ruminant livestock when grown under high nitrate conditions. If variation among inbred lines can be documented for nitrate concentration, it may be possible to reduce nitrate accumulation within forage sorghum hybrids by selecting inbred lines having lower nitrate accumulation. The goal of this study was to evaluate a diverse set of male‐sterile sorghum inbred lines grown under high nitrate conditions, to observe if genotypic variation exists among lines used to produce forage sorghum hybrids. Forty replicates of 20 sorghum A‐lines were grown in a greenhouse and received either 272 kg ha−1 or 408 kg ha−1 of actual nitrogen per plant through applications of ammonium nitrate. Variance components were extracted from linear regression models and reliability was estimated on an entry‐mean basis. Leaf and stem reliability estimates were 0.95 and 0.93, respectively. These reliability estimates indicate the genetic variance comprised most of the phenotypic variance, and that our measurements were consistent. Significant differences were also observed between genotypes for both leaf and stem tissue. Therefore, sufficient genetic variance exists for developing male sterile sorghum inbred lines having leaf nitrate concentrations below the potentially lethal toxicity threshold of 10,000 μg g−1.