Analysis of introgression from a tetraploid wild species, Oryza minuta, into cultivated rice, O. sativa
Oryza minuta, a tetraploid wild relative of cultivated rice, is an important source of resistance genes to bacterial blight (BB). Advanced backcross progenies (monosomic alien additional lines, MAALs and introgression lines) have been derived from interspecific cross, O. sativa x O. minuta using...
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| Format: | Thesis |
| Language: | English |
| Published: |
2002
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| Subjects: | |
| Online Access: | https://eprints.ums.edu.my/id/eprint/19714/1/Analysis%20of%20introgression%20from%20a%20tetraploid.pdf |
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| Summary: | Oryza minuta, a tetraploid wild relative of cultivated rice, is an important
source of resistance genes to bacterial blight (BB). Advanced backcross
progenies (monosomic alien additional lines, MAALs and introgression lines)
have been derived from interspecific cross, O. sativa x O. minuta using O.
sativa as recurrent parent. Fifty-nine putative MAALs and 158 introgression
lines have been examined for the presence of resistance gene(s) from O.
minuta. Chromosome analysis, screening for BB resistance, isozyme analysis
and microsatellite or simple sequence repeat (SSR) analysis were carried out
to detect alien introgression. Seventeen plants were detected with an extra
chromosome through cytogenetic analysis and have been identified as
MAALs. Of 158 introgression lines, 17 were found to be resistant to race 1
(PX061) of BS of Philippines, but none of the putative MAALs were resistant.
Isozyme analysis of 110 backcross derivatives did not reveal introgression
from O. minuta in all isozymes studied (AMP, SOH, ADH, lCD, GOT, MAL and
PGD). However, 11 progenies showed allele 2 of Adh1 and four progenies
showed allele 2 of Pgd1, while another 17 progenies showed allele 2 in both
Adh1 and Pgd1. All these alleles were not found in both parents.
Unfortunately, none of these progenies were resistant to race 1 of BS of
Philippines. Introgression was detected using SSR marker. SSR markers
showed about 28% polymorphism between O. sativa and O. minuta. Of the
76 polymorphic SSR markers used, 28 markers detected introgression from
O. minuta. SSR analysis of the putative MAALs and introgression lines
indicated that small segments from O. minuta had been transferred into O.
sativa. The results from this study showed SSR markers are efficient markers
for detecting introgression. |
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