# Effect of a novel dwarfing mutant site on chromosome 4B on agronomic traits in common wheat

## TL;DR

A new dwarfing gene in wheat, Rht-yz, improves lodging resistance but reduces yield traits, offering potential for breeding.

## Contribution

A novel dwarfing gene, Rht-yz, is identified and characterized for its unique mechanism and agronomic effects in wheat.

## Key findings

- Rht-yz improves lodging resistance by reducing plant height and increasing stem strength.
- Rht-yz negatively affects tiller number, biomass, and yield per plant.
- Rht-yz increases crude protein, wet gluten, and starch content in wheat.

## Abstract

The introduction of dwarfing genes triggered a wave of “green revolution”. A number of wheats dwarfing genes have been reported in previous studies, and only a small fraction of these have been applied to production practices. Therefore, the development of novel dwarfing genes for wheat is of great value. In this study, a novel dwarfing site, Rht-yz, identified in the Yanzhan mutation, is located on chromosome 4B (30-33MB) and its mechanism of action is different from that of Rht-B1b (C-T mutation), but whether it affects the Rht-B1a (TraesCS4B02G043100) or other genes is unclear. Exogenously applied GA3 experiments showed that Rht-yz is one of the gibberellin-insensitive dwarf genes. The effects of the dwarf gene Rht-yz on agronomic traits in wheat were evaluated in the field using Yanzhan, Yanzhan mutations, F2:3 and F3:4 lines. The results showed that Rht-yz improved lodging resistance by reducing plant height, increasing diameter, wall thickness and mechanical strength of the basal stem. In terms of yield traits, Rht-yz had negative effects on tiller number plant-1, biomass plant-1 and yield plant-1, but had no significant effect on harvest index, 1000-kernel weight and spike traits. In addition, Rht-yz significantly increased crude protein, wet gluten and starch content. Therefore, the rational use of the new dwarfing site Rht-yz has potential and value in dwarf wheat breeding.