Abstract:
Objective To transfer the broad-spectrum rice blast resistance gene, Pi9, to the restorer line Shuangkangmingzhan for improving its disease resistance.
Method The Sanming dominant male sterile line, a carrier of the Pi9 gene, was used as the intermediate “bridge” for the gene transduction experiment. Using the molecular marker assistance selection method, from each backcross generation the male sterile plants with Pi9 marker genotype were selected to backcross- mate with Shuangkangmingzhan until the self-homozygous Pi9 gene marker in the fertile plant was detected. Then, from the selected plant in the BC4F1 generation of the Shuangkangmingzhan disease-resistant isogenic line, the target sterile gene was obtained.
Result Of the 6 improved lines selected, 5 were identified by the field resistance verification with significantly improved resistance to rice blast. The combining abilities and agronomic traits of the lines were compared and analyzed to show that the improved line Y25-1 possessed the best general combining ability with a strong blast resistance. Since its main agronomic traits were similar to those of Shuangkangmingzhan, it could conceivably be considered a surrogate of the disease-resistant Shuangkangmingzhan for breeding purpose.
Conclusion For an improved blast resistance on rice, the successful transferring Pi9 gene from Shuangkangmingzhan onto Y25-1 through the use of the Sanming dominant male sterile line as an intermediate “bridge” provided a new venue for the breeding.
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