Semi-Dwarfing Reduced Height Genes Hardly Influenced Gluten Protein Composition While Extreme Dwarfing Genes Decreased Glutenins in Wheat

Abstract

The introduction of reduced height (Rht) genes into wheat during the Green Revolution led to lower plant height, but their effect on protein composition was unknown. Therefore, the protein composition of near isogenic lines (NILs) of four Triticum aestivum genotypes with five different Rht allele/allele combinations was compared to the tall wild-type (rht) by modified Osborne fractionation. The semi-dwarfing (Rht1, Rht2) and the dwarf Rht gene combination (Rht1 + 2) only had a small effect on protein composition. The extreme dwarfing genes (Rht3 and Rht2 + 3) decreased glutenin content leading to higher gliadin-to-glutenin ratios compared to the tall wild-type (rht). A strong environmental influence on the protein composition was observed. The introduction of the semi-dwarfing and dwarfing Rht genes (Rht1, Rht2, Rht1 + 2) that are predominantly present in modern wheat does not represent the primary factor contributing to the observed variation in protein composition between modern and pre-Green Revolution wheat cultivars. The extreme dwarfs Rht3 and Rht2 + 3 are not recommended to be included in wheat breeding programs due to their lower glutenin content. The high number of harvest years and biological replicates strengthen our findings. To our best knowledge, this is the first study that conducted Osborne fractionation on NILs with different Rht alleles.