Development of monosomic alien addition lines and introgression of genes from Oryza australiensis Domin. to cultivated rice 0. sativa L.
1994
Multani, D.S. | Jena, K.K. | Brar, D.S. | Reyes, B.G. de los | Angeles, E.R. | Khush, G.S. (International Rice Research Inst., Manila (Philippines))
Oryza australiensis, a diploid wild relative of cultivated rice, is an important source of resistance to brown planthopper (BPH) and bacterial blight (BB). Interspecific hybrids between three breeding lines of Oryza sativa (2n 24, AA) and four accessions of O. australiensis (2n =24, EE) were obtained through embryo rescue. The crossability ranged from 0.25% to 0.90%. The mean frequency of bivalents at diakinesis/metaphase 1 in F1 hybrids (AE) was 2.29 to 4.85 with a range of 0-8 bivalents. F1 hybrids were completely male sterile. No BC1 progenies were obtained even after pollinating 20,234 spikelets of AE hybrids with O. sativa pollen. The artificially induced autotetraploid of an elite breeding line (IR31917-45-3-2)were crossed with O. australiensis (Acc. 100882) and, following embryo rescue, produced six F1 hybrid plants (AAE). These triploid hybrids were backcrossed to O. sativa. The chromosome number of 16 BC1 plants varied from 28 to 31, and all were male sterile. BC2 plants had 24-28 chromosomes. Eight monosomic alien addition lines (MAALs) having a 2n chromosome complement of O. sativa and one chromosome of O. australiensis were selected from the BC2 F2 progenies. The MAALs resembled the primary trisomics of O. sativa in morphology. The identity of the alien chromosome was verified at the pachytene stage of meiosis. The alien chromosomes paired with the homoeologous pairs to form trivalents at a frequency of 13.2% to 24.0% at diakinesis and 7.5% to 18.5% at metaphase 1. The female transmission rates of alien chromosomes varied from 4.2% to 37.2%, whereas three of the eight MAALs transmitted the alien chromosome through the male gametes. BC2 progenies consisting of disomic and aneuploid plants were examined for the presence of O. australiensis traits.
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