Chapter 1
Chapter 1
Bridging Biodiversity and Breeding: Characterisation of Wild Rice (Oryza species) Accessions and Development of Novel Interspecific Germplasm to Broaden the Genetic Base
Simple Summary
Wild Oryza species constitute a critical reservoir of genetic diversity for rice improvement, offering adaptive traits for resistance to major biotic and abiotic stresses. Key gaps in the utilisation of these genotypes are mainly the lack of systematic characterisation of non-AA genome species, underscoring the need for uniform descriptors and genomics-enabled evaluation. This study synthesises detailed morphological characterisation of Oryza accessions with a species coverage of fifteen wild species, along with two cultivated species, highlighting their trait diversity and the importance of this unexplored genetic resource for pre-breeding.
Abstract
Abstract
Enormous genetic diversity exists in rice germplasm, including wild and weedy relatives, though they remain unexplored within in situ or ex situ collections. Characterisation and utilisation of the available biodiversity in plant breeding is essential for the detection of novel traits or genes for climate resilience. In this study, ninety-seven rice genotypes, including ninety rice accessions belonging to various Oryza species and seven check cultivars with an Oryza sativa background, were characterised for quantitative morphological characters following the guidelines based on distinctiveness, uniformity and stability test by the Protection of Plant Varieties and Farmers' Rights Authority, India. Characterisation of the genotypes based on thirty-nine important distinctiveness, uniformity and stability morphological descriptors revealed polymorphism in thirty-five traits, confirming high morphological diversity among wild rice accessions and distinguishing and unique traits from other wild accessions for the utilisation in pre-breeding programmes. Genotypes such as WD5_6, WD10_4, and WD3_3 consistently expressed a favourable combination of broad and long leaves, extended panicle length, and well-branched panicles with higher panicle number. In addition, these genotypes showed purple pigmentation across multiple vegetative and reproductive organs, indicating stable and enhanced anthocyanin accumulation. Accessions WD10_4 and WD3_3 also represent valuable donors for panicle architecture and yield component enhancement, while genotypes such as WD17_15 and WD12_8 may serve as specific donors for panicle length and branching traits. Characterisation studies and detection of unique traits provide the empirical foundation for conservation decisions, taxonomic clarity, and pre-breeding applications. Interspecific crosses in the genetic background of elite cultivars with donor species viz., O.
barthii, Oryza glaberrima and Oryza rufipogon were developed as pre-breeding materials for further crop improvement as well as for the identification of novel genes of agronomic importance.