The Green Revolution genes Rht-B1b and Rht-D1b encode truncated DELLA proteins that confer gibberellin (GA)-insensitive semi-dwarfism in wheat. Their roles in reducing plant height and enhancing lodging resistance are well established, but their pleiotropic effects on specific components of plant architecture require further genetic dissection. Here, we reveal a previously unrecognized role of Rht-D1b in regulating tiller angle, a key determinant of canopy architecture. Quantitative trait locus (QTL) mapping identified Rht-D1b as a major locus controlling tiller angle. Functional validation showed that Rht-D1b not only reduces plant height but also increases tiller angle and tiller number, thereby optimizing canopy structure for enhanced yield potential. Transcriptome profiling indicated that Rht-D1b modulates the expression of genes involved in auxin signaling and polar auxin transport. Broad-scale phenotyping across diverse wheat accessions demonstrated that both Rht-B1b and Rht-D1b significantly increase tiller angle and leaf area index, with double mutants exhibiting the strongest effects on tiller architecture. Notably, the frequency of Rht-B1b and Rht-D1b has risen in modern cultivars, coinciding with a historical trend toward wider tiller angle. Together, these findings establish a novel pleiotropic role for the Green Revolution genes, demonstrating that they not only reduce plant height but also coordinate tiller angle and tiller number to optimize canopy architecture, ultimately elevating yield in wheat.
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Open Access
Research paper
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To discover new high yield genes in wheat by association analysis, which can provide technical supports for the innovation and genetic improvement of high yield germplasm resources in wheat.
Totally 188 bread wheat cultivars in Xinjiang were genotyped using the wheat 55K genotyping assay. GWAS was carried out to identify the signifcant single nucleotide polymorphisms (SNPs) which were associated with 9 wheat yield traits in 6 environments. The MLM algorithm in TASSEL5.0 was used to analyze the nine traits related to wheat yield traits.
Totally 1309 SNPs explained 7.259%-70.792% of the phenotypic variation. 38 SNP loci were identifed, which were significantly correlated with 5 plant height weight SNP loci, 10 spike length weight SNP loci, 10 spikelet number SNP loci, 6 fertile spikelet number SNP loci, 6 spike grain number SNP loci, and 1 thousand grain weight SNP loci. These loci can explain 9.10%-23.81% of phenotypic variations. Comparing these 38 loci with the published wheat genome loci, only 3 functional genes were found, which annotated with gene function. There genes are: TraesCS2A01G448800 on chromosome 2A, which is close to the plant height associated site AX-108794050 and is related to the metabolic synthesis of transcription factor bHLH71; TraesCS2A01G448800, located on chromosome 1A at a distance similar to the spike length associated site AX-110689765, is related to protein coding; TraesCS4B01G031100, located on the 4B chromosome at a distance similar to the 1000 grain weight associated site AX-110399975, is associated with the encoding serine/threonine protein kinase SD1-8 and is involved in regulating cell proliferation and differentiation.
38 QTL loci associated with wheat yield traits were detected. After verification, it was found that the associated excellent alleles have the effect of reducing plant height, increasing spike length, spikelet number, fertile spikelet number, grain number per spike, and thousand grain weight.
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