Researchers identify key genes in wheat spikes

Chinese researchers developed a high-resolution phenotyping platform that allowed them to accurately map 54 morphological characteristics of wheat ears in 1.359 accessions. Their study indicates how the selection and combination of genetic variants (haplotypes) throughout the XNUMXth century may have contributed to increased ear volume.

The team analyzed data from 306 traditional varieties from various regions around the world and 1.053 accessions released between 1900 and 2020 in China. The genetic analysis involved more than 40 million SNP markers, allowing them to trace the origin, selection, and impact of alleles linked to the ear.

Haplotypic combinations were identified as the main determinants of variations in ear shape and volume, critical components for grain yield.

Ear volume

The wheat ear is made up of structures called spikelets, which produce flowers with anthers, carpels, and glumes. Scientists evaluated five equal sections of the ear, measuring width, thickness, area, and volume in frontal and lateral views. Ear thickness (lateral width) and frontal width showed a strong positive correlation with ear weight and grain weight per ear.

While ear length remained stable over time, width and thickness increased significantly. The genetic selection strategy overcame a natural limitation: the negative correlation between long ears and wide/thick ears, common in traditional lines. This breakthrough allowed for larger ears with a greater number of kernels.

Selection by regions

Phylogenetic analysis divided global accessions into two main groups: Asian and European. In China, accessions were grouped into four release phases: pre-1960, 1961–1980, 1981–2000, and 2001–2020. Genetic diversity (π) and population differentiation (Fst) confirmed that the introduction of foreign varieties was crucial in enriching the genetic base of modern Chinese wheat.

During the breeding process, unfavorable haplotypes (linked to smaller ears) were gradually replaced by superior genetic combinations. The frequency of haplotypes favorable for ear volume increased from 12,6% before 1960 to 61,1% after 2000.

Favorable haplotypes

Even with advances in genetic improvement, many favorable haplotypes remain underutilized, especially in regions such as West Asia and Africa. Efficient haplotype combinations, capable of increasing volume across multiple sections of the ear (from base to top), remain present in less than 30% of the accessions analyzed.

Furthermore, the analysis showed that ear morphology can be independently regulated in different parts—top (P1), center (P2–P4), and base (P5). This discovery paves the way for targeted genetic manipulations of specific parts of the ear, with the potential for adaptation to diverse environments.

Molecular design of the spike

The study functionally validated two candidate genes—TraesCS6B02G126000 and TraesCS1D02G068300—responsible for increased ear volume in the apical and basal parts of the ear, respectively. Recombinant lines and doubled haploid populations confirmed that introducing specific alleles into these genes can increase ear volume by up to 18%.

These genes have been used in marker-assisted breeding programs. One of the most successful cases was the creation of an isogenic line (BBC-154), in which the introduction of a specific genetic pattern increased ear volume by 53,2% compared to the parental variety.

Further information at doi.org/10.1016/j.celrep.2025.116120