Gene Discovery in Squash Could Improve Hybrid Seed Production
01 November 2026, Almería, ES: Researchers at the University of Almería in southern Spain have identified a gene that controls how well female flowers develop in squash and its relatives, a finding that could give seed companies a new molecular tool for producing hybrid seed more reliably in one of the world’s most widely grown vegetable crop families. The study, led by professor Manuel Jamilena and published October 16, 2026 in the Journal of Experimental Botany, focuses on Cucurbita pepo, the species that includes zucchini, pumpkin, acorn squash and several other summer and winter squash varieties.
The research centers on a plant hormone called gibberellin, which regulates many aspects of plant growth, including stem elongation and flower development. The team studied plants carrying a mutation in a gene they call CpGA3ox1B, which is involved in producing gibberellin inside the plant. Mutant plants with a non-functioning copy of this gene grew as dwarfs and produced female flowers that stayed small, failed to open properly, and could not be fertilized, while male flowers on the same plants developed normally.
By comparing gene activity between male and female flowers, the researchers found that healthy female flowers switch on the CpGA3ox1B gene more strongly than male flowers do, which drives faster growth through higher levels of active gibberellin inside the flower. When the team treated the dwarf, infertile mutant plants with a form of gibberellin called GA3, normal flower growth and fertility returned, confirming that the hormone itself, and not some other side effect of the mutation, was responsible for the problem. Treating the same plants with two other plant hormones, ethylene and jasmonic acid, did not restore fertility, which helped the researchers rule out those pathways as the direct cause.
How plants decide, then grow
The findings add detail to a longer-running question in cucurbit biology: how plants decide whether a given flower develops as male or female, and then how that flower actually grows once the decision is made. Squash plants, like many cucurbits, produce separate male and female flowers on the same plant rather than flowers containing both sexes, and the ratio and timing of each type strongly affects fruit set and yield. Earlier research, including previous work from the same University of Almería group, had already shown that the hormone ethylene drives the initial decision of whether a flower becomes male or female. The new study shows that gibberellin acts afterward, controlling how much the corolla (the flower’s petals) and the pistil (its female reproductive structure) grow once a flower has already been assigned as female.
(function() { var grid = document.getElementById(‘hln-grid’); if (!grid) return; fetch(‘https://www.global-agriculture.com/wp-json/wp/v2/posts?per_page=4&_fields=title,link,date’) .then(function(res) { return res.json(); }) .then(function(posts) { if (!Array.isArray(posts) || posts.length === 0) { grid.innerHTML = ”; return; } grid.innerHTML = posts.map(function(p) { var d = new Date(p.date); var dateStr = d.toLocaleDateString(‘en-GB’, { day: ‘numeric’, month: ‘short’ }); var title = p.title && p.title.rendered ? p.title.rendered : ”; return ‘
‘; }).join(”); }) .catch(function() { grid.innerHTML = ”; }); })();
The researchers also found that two other hormones, auxin and cytokinin, work alongside gibberellin to support female flower growth, while ethylene, abscisic acid and jasmonic acid work against it once the growth stage begins, suggesting a layered hormonal system rather than a single on-off switch. Using gene activity data from the mutant and normal plants, the team flagged a transcription factor called MYB62, a protein that turns other genes on or off, as a likely link between the ethylene signal that sets flower sex and the gibberellin signal that drives growth afterward, though confirming that specific link will require further study.
A molecular target for breeders
For commercial breeders, the practical interest in this kind of research is in producing hybrid squash seed more efficiently. Hybrid seed production in cucurbits typically depends on controlling which flowers on a parent plant can be fertilized and by what pollen, and breeders already use gibberellin sprays in commercial nurseries to influence flowering patterns in cucurbit crops. A clearer picture of exactly which genes and hormone pathways control female flower fertility gives breeders a more precise set of molecular targets, potentially for marker-assisted selection or gene editing approaches, rather than relying only on external hormone sprays applied to whole plants.
The Journal of Experimental Botany study is a continuation of earlier work by the same Almería research group, which previously described how a related gibberellin gene, GA3ox1, affects dwarfism in squash. Cucurbits, as a crop family, include some of the world’s most economically important vegetable crops, among them cucumber, melon and watermelon in addition to the various squash species, and insights into flower development in one species often carry over to breeding programs in the others.
Also Read: New Case IH Puma 185 Tractor to Make Irish Debut at FTMTA 2026
Global Agriculture is an independent international media platform covering agri-business, policy, technology, and sustainability. For editorial collaborations, thought leadership, and strategic communications, write to pr@global-agriculture.com
