# Genetic Dissection of Plant Height Variation Between the Parental Lines of the Elite Japonica Hybrid Rice ‘Shenyou 26’

## TL;DR

This study identifies genetic factors influencing plant height in a high-yield rice hybrid, offering insights for improving rice breeding.

## Contribution

The study identifies and validates multiple QTLs, including SD1 allelic variants, controlling plant height in the rice hybrid ‘Shenyou 26’.

## Key findings

- Seven QTLs associated with plant height were identified in the DH population of ‘Shenyou 26’.
- qPH1.1 co-localizes with SD1, and a rare SD1-EQH allele in ‘Shen 9A’ reduces plant height.
- qPH9.1 significantly contributes to plant height variation, with the Shenhui26 allele increasing height.

## Abstract

Plant height is a key agronomic trait influencing both seed production and yield in hybrid rice. In the elite japonica hybrid ‘Shenyou 26’, optimal plant height differences between the restorer line (‘Shenhui 26’) and the male sterile line (‘Shen 9A’) are critical for efficient pollination. In this study, we dissected the genetic basis of plant height variation using a doubled haploid (DH) population derived from ‘Shenyou 26’. Multi-environment phenotyping and QTL mapping identified seven QTLs associated with plant height, among which qPH1.1 and qPH9.1 were validated. qPH1.1 co-localized with the semi-dwarf gene SD1, and ‘Shen 9A’ carries a rare SD1-EQH allele that potentially confers reduced height relative to the SD1-EQ allele in ‘Shenhui 26’. qPH9.1 also contributed significantly to plant height variation, with the Shenhui26 allele increasing plant height in backcross validation. These findings indicate that plant height variation in ‘Shenyou 26’ is controlled by multiple loci, including SD1 allelic variants and other complementary QTLs, providing valuable resources for fine-tuning plant architecture in rice breeding.