Main conclusion <p>The study successfully developed first of its kind subtropically adapted <i>ig1</i> gene-based paternal haploid inducer lines in maize with HIR of 0.57–2.50% for rapid conversion of inbreds into its CMS versions.</p> Abstract <p>Maternal haploid inducer (HI) lines are extensively used for development of doubled haploid (DH) lines in maize (<i>Zea mays</i> L.), whereas paternal HI lines cause exchange of cytoplasm, therefore serving as an efficient tool for rapid conversion of inbreds to its cytoplasmic male sterile (CMS) version. However, <i>indeterminate gametophyte1</i> (<i>ig1</i>) gene-based paternal HI lines are available for temperate climate. Here, effort has been made to develop the subtropically adapted paternal HI lines through marker-assisted selection of <i>ig1</i> gene. Eight F₂ populations developed from cross between temperate inducer and elite subtropical lines were genotyped using <i>ig1</i>-specific functional InDel marker (MGU-IG1-Hopscotch). Severe segregation distortion (SD) for <i>ig1</i> gene was observed in almost all F₂ populations. Male sterility was observed for majority of <i>ig1/ig1</i> homozygotes, with only three out of eight F₂ populations contributed to fertile <i>ig1/ig1</i> segregants. Mendelian ratio of 15 (fertile):1 (sterile) was observed in F₂ populations indicating the duplicate gene interaction between <i>ig1</i> and other unknown gene in governing male sterility. Significant effect of ‘genotype’, ‘environments’, ‘source of haploids’ and ‘genotype × environments’ was observed for haploid induction rate (HIR). HIR of newly developed paternal HI lines ranged from 0.57 to 2.50% with the mean of 1.37% across environments. However, PHM8I as a source of haploids exhibited higher HIR (1.47%) compared to PVQ9I (1.28%). The HI lines were also found superior in agronomic performance and ease of maintenance. Here, we present the first successful attempt to develop subtropically-adapted <i>ig1</i>-based paternal HI lines.</p>