Strategies and prospects of haploid induction in rice (Oryza sativa)

Being a model crop as well as a staple food crop, rice possesses a conspicuous position in plant sciences. Doubled haploid (DH) breeding in rice offers multiple advantages over conventional methods via accelerating the process of pure lines development. For ages, several methods have been devised for haploid production in rice. In vitro-based methods have demonstrated their potential in DH production, but these methods are further impeded by stringent requirements and restricted to few species. Further, unlike maize, the in vivo DH breeding technology is still impractical in rice. Recent findings of the key molecular players behind the haploid induction (HI) trait in maize and rice have shown their potential in rice improvement programmes. In this review, we have discussed different strategies of HI in rice particularly focusing on recent progress made for developing haploid inducer stock (HIS) by employing both conventional and modern approaches. It also focuses on future implications of HIS so that it can be incorporated in the pipeline of modernized rice breeding.