Haploid Induction Technologies in Plant Breeding

Haploid induction has emerged as a transformative approach in modern plant breeding, enabling the rapid production of homozygous lines. By generating plants that carry a single set of chromosomes, breeders can accelerate the fixation of desirable traits, reduce generation times and enhance genetic gain. Two principal routes of haploid induction are exploited in crops: in vivo systems that harness specialised inducer genotypes to trigger uniparental genome elimination during fertilisation, and in vitro techniques that derive haploid plants from cultured gametophytic cells. Recent advances have focused on elucidating the molecular mechanisms underpinning haploid induction, improving induction rates across diverse species, and integrating novel genome-editing tools. Centromere engineering, targeted mutagenesis of fertilisation-related genes, and high-throughput screening methods are collectively expanding the range of crops amenable to doubled haploid (DH) technology. This progress is reshaping breeding programmes worldwide, with applications spanning cereals, brassicas, cucurbits and horticultural species, and holds promise for tackling challenges such as climate resilience, disease resistance and yield enhancement.

Research from Nature Portfolio

Recent studies have illuminated fundamental mechanisms of haploid induction in maize. Single-nucleus sequencing of pollen from inducer lines revealed frequent chromosome fragmentation during the post-meiotic gametophyte stage, implicating aneuploid male gametes in triggering maternal haploidy. This finding reframes the mechanistic model of uniparental genome elimination and suggests new targets for engineering inducer lines with enhanced haploid induction rates. In parallel, loss-of-function mutations of a maize phospholipase D gene were shown to induce maternal haploids at rates comparable to established inducer alleles. When combined with existing mutations, these alleles exhibited synergistic effects, boosting haploid induction rates beyond 4 per cent. Transcriptome analysis of pollen from these mutants identified gametogenesis pathways and intercellular signalling processes as critical contributors to haploid formation. Together, these studies provide both mechanistic insight and practical genetic tools for the rational design of next-generation haploid inducers.

Haploid Induction Technologies in Plant Breeding publication trend

The graph below shows the total number of articles in haploid induction technologies in plant breeding across all publications each year (not limited to Nature Index journals).

Technical terms

Haploid: A plant cell or organism containing one complete set of chromosomes.

Doubled haploid (DH): A haploid plant subjected to chromosome doubling to restore diploidy and achieve complete homozygosity.

Haploid induction rate (HIR): The percentage of haploid progeny produced by an inducer line among all seeds harvested.

Uniparental genome elimination: The selective loss of one parental chromosome set following fertilisation, leading to haploid embryos.

Centromere-mediated haploid induction: A technique that employs modified centromeric histone proteins to provoke genome elimination.

Genome doubling: The process of restoring diploidy in haploid plants, often via chemical or spontaneous chromosome duplication.

References

1. A female in vivo haploid-induction system via mutagenesis of egg cell-specific peptidases. Molecular Plant (2023).
2. In vivo haploid induction in cauliflower, kale, and broccoli. Journal of Integrative Plant Biology (2024).
3. Creation of a watermelon haploid inducer line via ClDMP3-mediated single fertilization of the central cell. Horticulture Research (2023).
4. Single nucleus sequencing reveals spermatid chromosome fragmentation as a possible cause of maize haploid induction. Nature Communications (2017).
5. Loss-of-function alleles of ZmPLD3 cause haploid induction in maize. Nature Plants (2021).