Abstract:

Aiming at the problems of long breeding cycle and low homozygous efficiency in traditional rice breeding, in order to promote the innovation and accurate improvement of breeding technology, this paper systematically combs the development process of haploid breeding technology, focusing on the analysis of traditional methods such as anther culture in vitro and parthenogenesis/androgenesis, and inducing technology using CRISPR/Cas9-mediated targeted editing of key meiotic genes (e.g.,REC8, PAIR1, OsD1) and the parthenogenesis-related gene OsMTL, and systematically optimizes the key links such as induction, identification and chromosome doubling. The results demonstrate that technology integration has significantly enhanced haploid induction efficiency (from 0.5%-2% to 10%-15%), expanded the genotype editing scope and facilitated targeted trait improvement. The development cycle of doubled haploid (DH) lines has been shortened to 2-3 years, resulting in a 3-5 fold increase in breeding efficiency compared to conventional approaches. A multidimensional identification system integrating molecular markers and flow cytometry has been successfully established, and excellent varieties such as 'Zhonghua' series and 'Jingliangyou 202/181' were successfully cultivated. This review also highlights existing technical challenges, including the unclear mechanism of spontaneous haploid doubling and difficulties in eliminating chimeras. It is proposed that through deeper integration of smart breeding and synthetic biology, haploid breeding will advance rice breeding into a new design breeding stage, providing sustained technological support for ensuring food security.

Key words: haploid, haploid induction line, in vivo induction, gene editing, OsMTL