Genetic monitoring of Indian rice (Oryza sativa) cultivars over decadal periods employing gene-specific markers and yield component traits

Abstract

Context Regular genetic monitoring of rice diversity provides informed direction for plant breeders when selecting parents in breeding programs. Aims The investigation was conducted to assess the trends of decade-wise genetic diversity in popular Indian rice (Oryza sativa L.) genotypes. Methods We screened 62 genotypes including popular rice varieties released from the 1970s to 2010s in India along with landraces, using gene-specific markers and some of the key yield and yield-contributing traits. Key results Using gene-specific markers, genetic diversity has shown a downward trend from landraces to the 2010s. Qualitative analysis revealed that more alleles were present in landraces than released varieties. The disappearance of alleles was prominently observed in varieties released in the 1970s and even more so in the 2010s, which suggests that present-day cultivars are losing several valuable alleles of the key yield genes. Genetic diversity assessed using phenotypic data also exhibited a downward trend towards the 2010s. Molecular and phenotypic data on genetic diversity were used to group the rice genotypes, revealing that genotypes with common parents grouped together. Conclusions Genetic diversity has shown a downward trend from landraces to the 2010s, as assessed using both gene-specific markers and phenotypic data, although with slight deviations among various decades. Implications This study reinforces the fact that assessment of temporal trends in genetic diversity at regular intervals is warranted to meet future food demands while conserving on-farm crop diversity.