Genetic mapping and identification of Rht8-B1 that regulates plant height in wheat

Area of Science:

• Plant genetics
• Agronomy
• Wheat breeding

Background:

• Plant height (PH) and spike compactness (SC) are critical for yield in wheat.
• Identifying genes controlling these traits is vital for marker-assisted selection (MAS).

Purpose of the Study:

• To identify quantitative trait loci (QTLs) for PH and SC in wheat.
• To determine the causal gene for a specific PH QTL (qPH2B.1).
• To understand the genetic basis of PH variation for breeding applications.

Main Methods:

• Developed a high-density genetic linkage map using a recombinant inbred line (RIL) population (139 lines).
• Applied the Wheat 40K Panel for genotyping.
• Utilized genetic mapping, gene cloning, and gene editing to identify and validate the causal gene.

Main Results:

• Seven stable QTLs for PH (3) and SC (4) were identified across two environments.
• Rht8-B1 was confirmed as the causal gene for qPH2B.1.
• Specific variants in Rht8-B1 reduce PH by 3.6%–6.2%; gene editing confirmed a 5.6% height reduction.
• Rht8-B1's effect on PH is less than Rht8-D1; the Rht8-B1b allele is underutilized in breeding.

Conclusions:

• Rht8-B1 is a significant gene for controlling wheat plant height.
• Combining Rht8-B1b with other Rht genes could enhance lodging resistance.
• Findings provide valuable insights for MAS in wheat breeding programs.