Journal of Agricultural Science (1998) 130, 423-430

P. Kaushal and P. Ravi (1998)
Crossability of wild species of Oryza with O. sativa cvs PR 106 and Pusa Basmati 1 for transfer of bacterial leaf blight resistance through interspecific hybridization
Journal of Agricultural Science 130 (4), 423-430
Abstract: Fourteen rice accessions resistant to bacterial leaf blight (BB), caused by Xanthomonas oryzae pv. oryza (Xoo) and belonging to nine wild Oryza species representing three genomic groups: AA (O. nivara, O. barthii, O. longistaminata, O. rufipogon and O. meridionalis), BBCC (O. punctata, O. malampuzhaensis and O. minuta) and CCDD (O. latifolia) were used to produce hybrids with two O. sativa (2n=24, AA) cultivars PR 106 and Pusa Basmati 1 (PB 1). The seed set in similar genome crosses ranged between 1·4 and 79% depending upon the rice cultivar used. In general, PR 106 showed better crossability with the wild species. Hybrids were obtained from intergenomic crosses with O. malampuzhaensis, O. latifolia and O. punctata, using embryo rescue. Morphologically, the hybrids were more vigorous than their parents and tended to resemble their male parent. Intragenomic hybrids showed little fertility (0·24-8·04%), while the intergenomic hybrids were completely sterile. Meiotic studies revealed irregularities in cell division, with a high frequency of univalents (12·17-18·75), fewer bivalents (2·43-5·80) and occasional multivalents, in intragenomic hybrids. The intergenomic hybrids were characterized by a very high frequency of univalents (34·98-35·35). The reaction of the hybrids to BB revealed the presence of both dominant and recessive genes in the wild gene pool. The hybrids with O. longistaminata, O. punctata, O. latifolia and O. malampuzhaensis showed resistance in the F₁ generation, and hence they were likely to carry dominant genes for resistance, while the hybrids with O. barthii, O. nivara, O. meridionalis and O. rufipogon were susceptible and hence carried recessive genes for resistance.
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Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Xanthomonas oryzae	Rice (Oryza)