Multiple cytokinin elevates indirect regeneration potential of indica rice mature embryo

Abstract

The concept of producing high quality mature seed derived callus competent to genetic transformation followed by efficient full plant regeneration is not unique in rice. But the process is lacking in terms of regeneration efficiency, genotype dependency especially in indica rice. Further, most of the research has only been focused on elite indica cultivars and popular local varieties are neglected. Our extensive literature study also revealed that among all the factors responsible for higher rice regeneration efficiency, the combination, concentration, and type plant growth regulators (PGRs) are mostly responsible for indica rice genotypes. Hence, the present study is focused on standardization of popular local indica rice cultivars for callus induction and regeneration by tweaking the PGRs in culture media, according to their amenability. The plant regeneration potential was assessed on both traditional organogenesis frequency and morphology-based scoring matrix. This revealed the best suitable PGR concentration-combination for efficient organogenesis and the genotype Khitish to be most responsive for indirect regeneration (78.68 ± 1.50 %). The highly polymorphic SSR marker based clonal fidelity test also validated the absence of somaclonal variation among the regenerated plants. This study would be helpful in improving the regeneration potential in local indica rice varieties and genetic transformation studies.