Pedigree-based genetic diversity analysis of improved rice (Oryza sativa L.) varieties in the Philippines
1995
De Leon, J.C. | Carpena, A.L. (Philippine Rice Research Inst., Maligaya, Munoz, 3119 Nueva Ecija (Philippines). Plant Breeding, Genetics and Biotechnology Div.)
The genetic diversity of 67 rice varieties developed in the Philippines from 1960 to 1994 by various research institutions was analyzed using a pedigree-based measure of relationship between individuals/groups, namely, coancestry. Results of the analysis showed a mean coancestry of 0.143 for all possible pairings of the 67 varieties, suggesting that these varieties were generally related through some common donor parent(s) of important genes. To ensure that these varieties accumulated the basic genes for desirable traits and general adaptation, rice breeders resorted to a genetic core of 19 ancestral parents from 57 initial landraces. Among the varieties evaluated, IR36 showed the highest mean coancestry with the other varieties of 0.254, suggesting a great similarity of its lineage with those of the other cultivars. Other materials with relatively high coancestries with the other varieties are IR8, IR24, IR50, IR42, IR72, BPI Ri-12, IR66, IR74, and PSB Rc10 (O.244, 0.233, 0.222, 0.221, 0.217, 0.207, 0.206, and 0.203, respectively). On the other hand, PSBRc16, BPIRi-10, BPI 3-2, BPI Ri-1, BPIRi-3, PSB Rc1, C22, UPL Ri-2, UPL Ri-5, UPL Ri-7 and BPI Ri-6 are least related to the other varieties by pedigree (0.00, 0.030, 0.030, 0.038, 0.038, 0.044, 0.06, 0.061, 0.073, 0.078 and 0.084, respectively). The analysis also indicated that IR20 and IR30 are very much related by genetic descent (0.627) and so are IR56 and IR60; IR32, IR38, and IR40; and IR36 and IR42 with coancestries of 0.618, 0.610 and 0.594, respectively
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