{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,20]],"date-time":"2026-05-20T06:12:17Z","timestamp":1779257537217,"version":"3.51.4"},"reference-count":46,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,5,20]],"date-time":"2026-05-20T00:00:00Z","timestamp":1779235200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Plant Sci."],"abstract":"<jats:p>Spontaneous haploid genome doubling (SHGD) is a valuable trait in maize breeding, enabling the development of doubled haploid (DH) lines without chemical chromosome doubling. However, SHGD is a rare phenotype, expressed in only a small fraction of maize germplasm, making its identification resource-intensive. This study evaluated the efficiency of a two-stage field screening approach designed to identify maize genotypes with high haploid male fertility (HMF), a key indicator of SHGD potential. Simulation analyses showed that evaluating 50 haploid plants per genotype, combined with a 25% HMF threshold, provides an optimal balance between detection accuracy and resource efficiency. Across three growing seasons, HMF exhibited a highly skewed distribution, with most genotypes showing low HMF and a small subset exceeding 30% HMF. Field evaluations conducted in 2022, 2023, and 2024 consistently identified high-performing genotypes, including A427, N525, N516, and NK778, which maintained stable HMF expression across years. A genome-wide association analysis identified genomic regions associated with HMF. Our two-stage screening approach identified both SHGD donor lines and genomic loci and candidate genes for HMF.<\/jats:p>","DOI":"10.3389\/fpls.2026.1837152","type":"journal-article","created":{"date-parts":[[2026,5,20]],"date-time":"2026-05-20T05:46:13Z","timestamp":1779255973000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["A two-stage screening approach integrated with GWAS for rare phenotypes such as spontaneous haploid genome doubling in maize"],"prefix":"10.3389","volume":"17","author":[{"given":"Mercy","family":"Fakude","sequence":"first","affiliation":[{"name":"Department of Agronomy, Iowa State University","place":["Ames, IA, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tyler L.","family":"Foster","sequence":"additional","affiliation":[{"name":"Department of Agronomy, Iowa State University","place":["Ames, IA, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yu-Ru","family":"Chen","sequence":"additional","affiliation":[{"name":"Department of Agronomy, Iowa State University","place":["Ames, IA, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ann","family":"Murithi","sequence":"additional","affiliation":[{"name":"Department of Agronomy, Iowa State University","place":["Ames, IA, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Siddique Imran","family":"Aboobucker","sequence":"additional","affiliation":[{"name":"Department of Agronomy, Iowa State University","place":["Ames, IA, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ursula Karoline","family":"Frei","sequence":"additional","affiliation":[{"name":"Department of Agronomy, Iowa State University","place":["Ames, IA, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Philip M.","family":"Dixon","sequence":"additional","affiliation":[{"name":"Department of Statistics, Iowa State University","place":["Ames, IA, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thomas","family":"L\u00fcbberstedt","sequence":"additional","affiliation":[{"name":"Department of Agronomy, Iowa State University","place":["Ames, IA, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2026,5,20]]},"reference":[{"key":"B1","doi-asserted-by":"crossref","DOI":"10.1007\/978-1-0716-2253-7_16","article-title":"Protocols for in vivo doubled haploid (DH) technology in maize breeding: From haploid inducer development to haploid genome doubling","volume-title":"Plant Gametogenesis. 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