Morphological and Genetic Diversity Analysis of Rice Accessions (Oryza sativa L.) Differing in Iron Toxicity Tolerance
Loading...
Date
2013
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Crop Science and Biotechnology
Abstract
A major emphasis in breeding for iron toxicity tolerance in rice is to identify differences that are associated with resistance and
harness them for genetic improvement. In this study, thirty accessions, including IRRI gene bank accessions, two varieties from
Brazil, 8 cultivars from West Africa and 10 cultivars from Uganda were analyzed for sensitivity to iron toxicity, and genetic diversity
using morphological and SSR markers. Two genotypes, IR61612-313-16-2-2-1 and Suakoko 8 showed significantly high resistance
with an average score of ² 3.5 on 1 - 9 scale. The SRR markers were highly informative and showed mean polymorphism information
content (pic) of 0.68. The PIC values revealed that RM10793, RM3412, RM333, RM562, RM13628, RM310, RM5749, and
RM154 could be the best markers for genetic diversity estimation of these rice cultivars. Diversity at the gene level showed an average
of 4.61 alleles ranging from 2 to 12 per locus. Mean gene diversity (H) value for all SSR loci for the 30 genotypes evaluated was
0.69 but was decreased to 0.53 when analysis was performed on Ugandan accessions. The low genetic diversity found among the
Ugandan accessions is the evidence of a narrow genetic base, and such a scenario has a potential vulnerability for resistance break
down. A low correlation was detected between the observed molecular and morphological datasets. This means that a combination of
morphological traits and SSR analysis would be required when assessing genetic variation under iron toxic conditions, and could be a
practical strategy for breeders when planning crosses. A distinction between the resistant and susceptible accessions in both phenotyping
and SSR datasets suggests the presence of unique alleles that could be harnessed for improvement of rice against iron toxicity.
Description
Keywords
Genetic diversity, Iron toxicity, Phenotypic variation, Phospho-Molybdate dye assay, SSR
Citation
Onaga, G., Egdane, J., Edema, R., & Abdelbagi, I. (2013). Morphological and genetic diversity analysis of rice accessions (Oryza sativa L.) differing in iron toxicity tolerance. Journal of Crop Science and Biotechnology, 16(1), 53-62. DOI No. 10.1007/s12892-012-0104-0