Partial resistance for rice blast from lines without major genes based on DNA markers
1998
Tabien, R.E. | Marchetti, M.A. (Philippine Rice Research Inst., Munoz, Nueva Ecija (Philippines))
Breakdown of resistance is generally associated with major genes and lost of resistance occurs in 2-5 years after cultivar release. To minimize this problem, breeding program re-focused strategies and begun to use horizontal or partial resistance. Partial resistance is mostly obtained from moderately resistant to highly resistant sources and very few have used sources with the typical susceptible reaction. Recombinant inbred lines (RILs) from `Lemont' and `Teqing' without major genes based on DNA markers were inoculated with five races of rice blast pathogen at the greenhouse and were evaluated at the blast nursery. These lines having spindle-shaped lesions during greenhouse inoculation were found variable in number of lesions/sq mm, lesion size (sq mm) at 10-17 days after inoculation (DAI), and change in lesion six (sq mm). Most of the lines showed partial resistance and very few lines were as susceptible as the check M-201. Lines susceptible to all five races had differential number of lesion and was found race specific. These lines had also variable reaction at the blast nursery which further showed that susceptible lines can be potential source of partial resistance and should not be selected against in the breeding program
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