The Improvement of Grain Sorghum Productivity, Black Pericarp Color, and Protein Digestibility
Abstract
Sorghum [Sorghum bicolor (L.) Moench] is an important cereal crop for the
semiarid regions of the world. The improvement of sorghum grain production and
sorghum grain quality are essential for the future of the crop. This study explores the
genetic gain of hybrid sorghum breeding programs and investigates the nature of two
important grain quality traits. A multi-environment trial was conducted that included
hybrids ranging from the 1950s to today. Genetic yield gains in grain sorghum are
increasing at approximately .008 t ha^-1 annually and many other physiological traits have
demonstrated changes as well. Also, a Fv5 recombinant inbred line (RIL) population
segregating for black and red pericarp color was evaluated in two Texas environments in
the summer of 2017. Heritability and repeatability estimates were calculated and
secondary plant metabolite biosynthesis genes were explored using RNAseq. The black
pericarp trait appeared to be moderately heritable. Many of the same genes involved in
3-deoxyanthocyanidins (3-DOA) production in leaf tissue during fungal invasion
appeared upregulated in black pericarp sorghum versus red pericarp sorghum. Finally,
sorghum grain protein digestibility was investigated in a biparental mapping population
and evaluated in two environments for two years. A near-infared spectrometry (NIR)
calibration curve for in-vitro protein digestibility was developed to assist the
phenotyping of this important quality trait. The protein digestibility trait was highly
heritable and a significant genotype x environment effect was observed. Understanding
key components of genetic gains in yield and other traits, as well as factors involved with important quality traits will benefit sorghum production in the future.
Citation
Pfeiffer, Brian Kevin (2017). The Improvement of Grain Sorghum Productivity, Black Pericarp Color, and Protein Digestibility. Doctoral dissertation, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /173127.