Haploid Induction in Indica Rice: Exploring New Opportunities

Abstract

Haploid plants are of significant interest to crop breeders due to their ability to expedite the development of inbred lines. Chromosome-doubling of haploids, produced by either in vitro or in vivo methods, results in fully homozygous doubled haploids. For nearly five decades, in vitro methods of anther and microspore culture have been attempted in many crops. In rice, in vitro methods are used with some success in japonica cultivars, although indica types have remained recalcitrant to a large extent. This review aims to explore the reasons for the lack of success of in vitro methods in indica rice and discuss new advancements in in vivo haploid induction protocols in other cereals and their relevance to rice. In particular, the current level of understanding of in vivo haploid inducer systems that utilize MTL and CENH3 mutants is analyzed in detail. One notable advantage of in vivo haploid induction systems is that they do not require tissue culture competence. This makes these methods more accessible and potentially transformative for research, offering a pragmatic approach to improving indica rice cultivars. By embracing these in vivo methods and harnessing the power of gene editing technologies like CRISPR/Cas9 systems, breeders can reshape their approach to indica rice improvement.

Unveiling the Genetic Basis Underlying Rice Anther Culturability via Segregation Distortion Analysis in Doubled Haploid Population

“…AC encompasses several essential steps, which include callus induction, plant regeneration, and chromosome doubling [6]. The effectiveness of AC can be influenced by multiple factors, such as the genotype and growth environment of the plant, the developmental stage of the anthers, the cold pretreatment of the explant, the nutrient composition and hormone levels of the culture medium, as well as the specific conditions employed during the anther culture process [2,4,[6][7][8][9][10]. Among these factors, the genotype is the main determinant of anther culturability.…”

In Vitro Regeneration of Chrysanthemum from Ovaries and Ovules Treated with Thermal and Chemical Stimuli: Morphogenic and Cytogenetic Effects

“…It was found that heat stress promotes haploid formation during centromeremediated genome elimination in Arabidopsis [16,17]. On the other hand, cold treatment or vernalization is commonly used to induce haploids in cereals such as rice, oats, and barley [18,19].…”