Euphytica (2002) 123, 379-386

Zhonghua Wang, Qingyao Shu, Gongyin Ye, Hairui Cui, Dianxing Wu, Illimar Altosaar and Yingwu Xia (2002)
Genetic analysis of resistance of Bt rice to stripe stem borer (Chilo suppressalis)
Euphytica 123 (3), 379-386
Abstract: Two transgenic Bt rice lines, KMD1 and KMD2, both containing asynthetic {it cry1Ab} gene from Bt, were crossed with conventional rice varieties. The inheritance of resistance to SSB of KMD1 and KMD2 was investigated through LSB and field examination of their progenies, e.g. F₁, BC₁ and F₂ populations. In LSBs, 100.0% of newly hatched SSB larvae died on the second day after feeding on leaf tissues of F₁ and GUS positive BC₁ plants, of which the area of leaf tissues consumed by SSB is also similar to that of transgenic parents.These results imply that the resistance of Bt rice to SSB is dominantly controlled and could be easily exploited in hybrid rice production. Field evaluation showed that segregation ratios for SSB resistance to susceptibilityin BC₁ populations fit the ratio of 1:1, which was also confirmed by LSBs. However, in F₂ populations, the ratio was significantly smaller than 3:1 for resistant to susceptible plants in all 6 indica × japonica (KMD1 and KMD2) crosses, though it fitted 3:1 in all 4 japonica × japonica crosses. The results implied that the resistance of Bt rice to SSB was controlled by a dominant gene which was present in a homozygous condition in both KMD1 and KMD2, but the inheritance could be affected by other factors. Assays for Cry1Ab protein showed that, in most crosses, the content of Cry1Ab is significantly higher in leaves of GUS positive F₁, BC₁ and F₂ plants than that in transgenic Bt parent plants, which accounts for the high resistance observed in these plants to SSB.
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Link to article at publishers website
Database assignments for author(s): Illimar Altosaar

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
resistance/tolerance/defence of host
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Chilo suppressalis	Rice (Oryza)
Bacillus thuringiensis genes in crops (entomopathogen)	Chilo suppressalis	Rice (Oryza)
Bacillus thuringiensis Cry1A-toxin (entomopathogen)	Chilo suppressalis	Rice (Oryza)