Variations in farmer's seed and genebank accessions of Milagro Filipino rice (Oryza sativa L.) released in Mexico in 1967
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abstract
Panicles from farmer's field plots of Milagro Filipino (MF), the miracle rice (IR8) released in Mexico in 1967, were grown to produce MF lines and field-evaluated for three years to determine the phenotypic variation and compare the derived lines with IR8 accession (PI 312627) from the gene bank. Morpho-agronomic data such as plant height, length and width of flag leaf, numbers of filled and unfilled grain, seed length and width, 1000-seed weight, awn length, and grain yield were gathered. Twenty SSR markers were used to evaluate genotypic differences among the MF lines and to compare these lines with eight IR8 accessions from the gene bank. Results showed significant variation in plant height, seed length and width, 1000-seed weight, awn length, and total grain per panicle, but not for panicle length, flag leaf length and width, and grain yield. Most of the MF derived lines were comparable to IR8 in several traits. The SSR markers revealed genotypic variation as six of the 20 markers detected differences in 20 MF lines genotyped. Heterozygous loci in three markers were found in two IR8 accessions and in one MF line. Fingerprints of 11 MF lines were similar to the five IR8 accessions (PI 338085, PI 400151, PI 408669, PI 431424 and PI 446985) obtained from the gene bank, while the remaining nine MF lines were similar to IRS accession PI 312627. These results indicated that after 40 years, the MF seed samples were similar to IR8 seed stock released in 1966 and 1967, and the seed producer and seed bank curators we able to maintain these variabilities. This report documents the phenotypic and genotypic status of IR8 received by a gene bank and farmer seeds after forty years since its release in 1967.
