Identification of Soybean (Glycine max) Check Lines for Evaluating Genetic Resistance to Sclerotinia Stem Rot

Abstract

Soybean production in the Upper Midwest of the United States is affected by Sclerotinia stem rot (SSR) caused by the fungal pathogen Sclerotinia sclerotiorum, and genetic resistance is an important management strategy for this disease. However, assessing genetic resistance to S. sclerotiorum is challenging, because a standardized method to examine resistance across genotypes is lacking. Using a panel of nine diverse S. sclerotiorum isolates, four soybean lines were assessed for reproducible responses to S. sclerotiorum infection. Significant differences in SSR severity were found across isolates (P < 0.01) and soybean lines (P < 0.01), including one susceptible, two moderately resistant, and one highly resistant line. These four validated lines were used to screen 11 other soybean genotypes to evaluate their resistance levels, and significant differences were found across genotypes (P < 0.01). Among these 11 genotypes, five commercial and public cultivars displayed high resistance and were assessed in field studies across the Upper Midwest growing region for their response to SSR and yield. These five cultivars resulted in low disease levels (P < 0.01) in the field which were consistent with greenhouse experiments. Yield was significantly different in fields with disease present (P < 0.01) and disease absent (P < 0.01), and the order of cultivar performance was consistent between environments where disease was present or absent suggesting resistance prevented yield loss to disease. This study suggests the use of a soybean check panel can accurately assess SSR resistance in soybean germplasm and aid in breeding and commercial soybean development.

Transgenic Improvement for Biotic Resistance of Crops

“…For improvement of horizontal resistance to non-specific parasitic pathotypes of saprophytic pathogens, such as Bhizoctonia solani and Hyaloperonospora parasitica (pathogens of maize sheath blight and rape downy mildew, respectively), as well as pathogenic viruses and phytophagous insects, it is a great challenge to pyramid the multiple dominant resistant genes into a single cultivar for developing broad-spectrum and durable resistance [37][38][39][40][41][42]. This challenge occurs even with the advances in distant hybridization, artificial mutation, double haploid technology, somatic hybrid, and DNA marker-assisted genotyping and selection [38,39,[43][44][45][46][47][48][49], due to the limitation of germplasm resources, the genetic background of minor polygenes, and negative correlation with yield and quality characteristics [50][51][52][53]. The application of agrochemicals is effective for the control of herbivory insects, but increases production costs and causes environmental pollution [54][55][56][57].…”

“…This challenge occurs even with the advances in distant hybridization, artificial mutation, double haploid technology, somatic hybrid, and DNA marker-assisted genotyping and selection [38,39,[43][44][45][46][47][48][49], due to the limitation of germplasm resources, the genetic background of minor polygenes, and negative correlation with yield and quality characteristics [50][51][52][53]. The application of agrochemicals is effective for the control of herbivory insects, but increases production costs and causes environmental pollution [54][55][56][57].…”

Geostatistical techniques to account for the heterogeneity ofFusariumwilt inoculum distribution in upland cotton field screening studies

“…For example, in maize yield trials, high‐producing commercial varieties are used for controls when analyzing new hybrids’ abiotic stress tolerance and provide a direct comparison of the performance of possible new varieties compared to what is currently commercially grown (Setimela et al., 2017). The use of checks is a widespread practice in agriculture variety development, including in programs for maize, wheat, sweet potato, soy, and cassava (Gasura et al., 2021; Mondal et al., 2016; Setimela et al., 2017; Sholihin et al., 2022; Webster et al., 2021); however, these checks only provide direct comparisons to adjacent plots, and their relevance diminishes the further a trial plot is located from the check.…”

Molecular Breeding to Overcome Biotic Stresses in Soybean: Update

“…Identification or development of resistant soybean genotypes against different diseases is a major challenge [ 20 ]. Molecular breeding technologyhas proven its efficiency in the transfer of genes toa desired cultivar.…”