Abstract
Protein digestibility (PD) is a quantitative trait that is generally lower in sorghum than other cereals such as corn & rice. This affects the ability for humans and animals to obtain vital nutrients from sorghum food products and feedstuffs. Previous efforts helped create and identify sorghum lines with highly digestible protein (HDP) phenotypes using mutagenesis. This creates variation for the trait that can be exploited by breeding programs. However, phenotyping large populations is highly time consuming using wet-chemistry techniques and can exhaust resources quickly, leading to bottlenecks in development of breeding objectives. Near-Infrared Spectroscopy (NIRS) offers a fast, non-destructive alternative to this approach. Increased ability to identify and characterize HDP phenotypes from diverse populations allows for effective trait utilization, specialized downstream applications, and identification of causative alleles for novel gene discovery and germplasm development. Here, we utilize a phenotyping pipeline that takes advantage of NIRS to predict PD in unknown mutant genotypes across generations, validate NIRS positives with wet chemistry, and eventually will be integrated with genetic analysis to investigate potential genetic and allelic variation for this sorghum PD. After wet chemistry validation, four candidate mutant EMS lines were found to display a 20-30% increase in PD compared to the wild-type progenitor line BTx623, the reference genome for sorghum. Screening large mutant populations for novel mutants with increased PD via NIRS allows for high-throughput and forward genetics approaches to efficiently develop germplasm for this trait, and shows potential as an approach for improvement of grain quality traits that are infeasible to phenotype in the field.
Keywords
NIRS, Sorghum Breeding, Protein Digestibility, Plant Phenotyping
DOI
10.5703/1288284318184
High Throughput Phenotyping for Improved Sorghum Protein Digestibility
Protein digestibility (PD) is a quantitative trait that is generally lower in sorghum than other cereals such as corn & rice. This affects the ability for humans and animals to obtain vital nutrients from sorghum food products and feedstuffs. Previous efforts helped create and identify sorghum lines with highly digestible protein (HDP) phenotypes using mutagenesis. This creates variation for the trait that can be exploited by breeding programs. However, phenotyping large populations is highly time consuming using wet-chemistry techniques and can exhaust resources quickly, leading to bottlenecks in development of breeding objectives. Near-Infrared Spectroscopy (NIRS) offers a fast, non-destructive alternative to this approach. Increased ability to identify and characterize HDP phenotypes from diverse populations allows for effective trait utilization, specialized downstream applications, and identification of causative alleles for novel gene discovery and germplasm development. Here, we utilize a phenotyping pipeline that takes advantage of NIRS to predict PD in unknown mutant genotypes across generations, validate NIRS positives with wet chemistry, and eventually will be integrated with genetic analysis to investigate potential genetic and allelic variation for this sorghum PD. After wet chemistry validation, four candidate mutant EMS lines were found to display a 20-30% increase in PD compared to the wild-type progenitor line BTx623, the reference genome for sorghum. Screening large mutant populations for novel mutants with increased PD via NIRS allows for high-throughput and forward genetics approaches to efficiently develop germplasm for this trait, and shows potential as an approach for improvement of grain quality traits that are infeasible to phenotype in the field.