APEDA - CDFD Centre for Basmati DNA analysis
QTL mapping of economically important traits of Basmati rice
Earlier investigations on genetic analysis of different accessions of rice revealed that the Basmati rices form a distinct cluster different from indica, japonica and javanica varietal groups suggesting that Basmati rice falls in phylogenetically divergent group. As for inheritance and breeding behavior are concerned, all the indices of grain appearance and cooking/eating qualities with the exception of amylose content and to some extent aroma have been reported to be polygenically controlled. For instance, amylose content is reported to be governed by single gene located on chromosome 6 i.e., waxy locus (wx) in association with modifier complex. Some researchers are of the opinion, that wx gene also controls gelatinization temperature and gel consistency. In case of aroma, most researchers believe that it is under the control of single recessive gene. Recently, a gene for fragrance (fgr) was identified on chromosome 8 which has homology to the gene that encodes betain aldehyde dehydrogenase 2 (bad2¬). Thus, the complex genetic architecture of unique traits of Basmati and tedious screening methodologies involved in quality testing have been serious constraints to breeding for quality of Basmati. Moreover, very limited information is available on the genetic basis of grain and cooking qualities of rice in general and basmati rice in particular.
In order to construct Basmati rice linkage map, we crossed a traditional basmati variety Basmati 370 and a semi dwarf variety Jaya to develop a F2 mapping population. 450 microsatellite primers were screened for the polymorphism between parents. Size variation was obtained in 208 loci; polymorphic markers were distributed in all the 12 chromosomes of the Rice genome. We obtained an F1 hybrid of the two parental strains, which was confirmed by using two microsatellite markers RM263 and RM339. Phenotypic data of F1 plants were taken. Hybrids exceeded parental strains for all the phenotypic traits. F1 were advanced to F2 population to be used as mapping population. The mapping population has been screened with polymorphic microsatellite markers and constructed a Basmati linkage map and identified many QTLs for different agronomic and quality traits.
Projects being pursued
- Fine mapping of the major or promising QTLs
- Identification of candidate gene(s) underlying the major or promising QTLs
Working group
- A Srividya
- Prof E A Siddiq Acharya, N G Ranga Agricultural University, Hyderabad, INDIA
- VLN Reddy, Acharya N G Ranga Agricultural University, Hyderabad, INDIA