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Genetic diversity analysis of Pakistan rice ( Oryza sativa ) germplasm using multiplexed single nucleotide polymorphism markers

ABSTRACT

Abstract A broad base of genetic diversity is crucial to provide variation to withstand biotic and abiotic stresses and to continue to make yield improvements. Pakistan has a wide range of climates and rice is ranked second as a staple food; however, very little is known in terms of rice genetic diversity in Pakistan with respect to global germplasm. This research was performed to investigate the genetic diversity and structure of the most commonly grown rice varieties in Pakistan, including the aromatic Basmati varieties, along with accessions from other countries. One hundred and five rice accessions were analyzed, including 21 Pakistan accessions, 44 IRRI lines, 6 wild rices, and 34 global accessions representing all five groups of rice as a reference in this study. These accessions were genotyped with 373 multiplexed SNP markers using the Illumina GoldenGate assay RiceOPA2.1 run at the Genotyping Services Lab at IRRI. The overall call percentage of the 373 SNPs across 105 accessions was 98.7 %. Structure analysis, principal coordinate analysis, and clustering with Neighbor Joining and UPGMA separated the genotypes in five major groups: indica, japonica, wild, aromatic and aus, while the Structure analysis at K = 7 further divided the indica cluster into 4 indica sub-groups. The Pakistan varieties were found in both the indica and aromatic clusters, but with an overall lower genetic diversity than seen in germplasm from other countries. Information on the diversity of rice germplasm can help guide future initiatives to widen the genetic base of rice cultivation in Pakistan.AbstractA broad base of genetic diversity is crucial to provide variation to withstand biotic and abiotic stresses and to continue to make yield improvements. Pakistan has a wide range of climates and rice is ranked second as a staple food; however, very little is known in terms of rice genetic diversity in Pakistan with respect to global germplasm. This research was performed to investigate the genetic diversity and structure of the most commonly grown rice varieties in Pakistan, including the aromatic Basmati varieties, along with accessions from other countries. One hundred and five rice accessions were analyzed, including 21 Pakistan accessions, 44 IRRI lines, 6 wild rices, and 34 global accessions representing all five groups of rice as a reference in this study. These accessions were genotyped with 373 multiplexed SNP markers using the Illumina GoldenGate assay RiceOPA2.1 run at the Genotyping Services Lab at IRRI. The overall call percentage of the 373 SNPs across 105 accessions was 98.7 %. Structure analysis, principal coordinate analysis, and clustering with Neighbor Joining and UPGMA separated the genotypes in five major groups: indica, japonica, wild, aromatic and aus, while the Structure analysis at K = 7 further divided the indica cluster into 4 indica sub-groups. The Pakistan varieties were found in both the indica and aromatic clusters, but with an overall lower genetic diversity than seen in germplasm from other countries. Information on the diversity of rice germplasm can help guide future initiatives to widen the genetic base of rice cultivation in Pakistan.tructureindicajaponica,aromaticaustructureindicaindicaindicaaromatic