Development of bacterial blight resistant basmati rice doubled haploids through anther culture
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Date
2014
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Punjab Agricultural University, Ludhiana
Abstract
The F2 population from the cross of bacterial blight (BB) resistant variety PB 3 (Xa21 + xa13) and the salinity tolerant variety CSR 30 was selected for the rapid generation of elite homozygous material in a shorter time by biotechnological inputs via marker assisted selection (MAS) and doubled haploidy. A total of 783 F2 plants were evaluated for BB resistance against most virulent and most prevalent pathotype PbXo VII under field conditions followed by molecular characterization of 303 resistant plants with gene specific markers xa13 promoter and pTA248 for xa13 and Xa21 genes respectively. From these twenty five, sixty nine and ninety seven plants were found to carry both xa13 + Xa21, xa13 and Xa21 genes in homozygous conditions respectively. The resistant plants were further used for the generation of doubled haploid plants through anther culture. Along with the resistant plants which were chosen selectively, six other F2 populations which involved PB 3, CSR 30 or RYT 3268 (BB resistant version of Basmati 370) as one of the parents were used for anther culture. Preliminary, anther culture studies were done on a set of three japonica, two indica and three basmati rice using standard anther culture protocol. Satisfactory callus induction frequency (CIF) of 38%, 5% and 4.6 % for japonica, indica and basmati genotypes respectively was observed with the standard protocol, however very poor plant regeneration could only be obtained. Based on these results refined strategy comprising of standard N6 media for callus induction and different plant regeneration media (PRM) combinations were used to generate doubled haploids (DH) from selected seven F2 populations. The CIF was found to vary from 1.4 to 11.2%. Maximum CIF was observed in the cross Pusa 1121 x RYT 3268 and minimum in CSR 30 x PB 3. Period of culturing also effected the CIF, the maximum being in anthers cultured within 4-7 days interval and minimum in 11-13 days of pretreatment. Observations on induced callus color indicated that majority of the calli were yellowish in color with a score of 4 and around 1/3rd were yellowish white with a score of 5. Among different PRM tested, the media MS V was found better having plant regeneration frequency (PRF) of 8.4% while the standard PRM had a low regeneration frequency of 3.1%. But majority of the regenerated shoots were albinos or light green and healthy plant regeneration could not be established. Thorough investigations on role of genotypes, environment and cultural conditions effecting anther culture response are required for the fine tuning of anther culture protocol for its practical applicability
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Doubled haploids