Fragrance Analysis among Recombinant Inbred Lines of Rice

The aroma or fragrance of Basmati rice is associated with the presence of 2-acetyl-1-pyrroline. Aroma in Basmati is reported to be monogenic recessive. Several PCR-based co-dominant markers based on RG28 locus were developed which can differentiate between fragrant and non-fragrant rice cultivars. For analysis of aroma among RILs derived from a diverse cross between CSR 10 and Taraori Basmati through SSD method both molecular as well as biochemical methods were used to clearly distinguish aromatic and non-aromatic RILs of rice RG28 locus specific markers. Recombinant Inbred Lines (RILs) among various mapping populations provide a noble material for linkage of marker and trait. RILs were analyzed for polymorphism using RG28 locus specific primers (BAD2, BADEX7-5, SCUSSR1). Biochemical analysis of aroma was performed with the 1.7% KOH solution and molecular analysis of aroma was carried out with microsatellite markers present on chromosome 8 to determine the extent of association between trait, marker and chromosome 8. Out of these, BAD 2 amplified aroma specific alleles having 256 bp in 72 lines, BADEX7-5 with 95 bp in 74 lines and SCUSSR1 with 129 bp in 79 lines. Mental test of significance detected by biochemical analysis of RILs (with 1.7% KOH) and molecular marker study revealed 97 , 95 and 90.1% of association of aroma with the markers, respectively. Some of the F10 lines amplified the heterozygous alleles by using the 2 sets of specific markers but did not show the presence of aroma as analyzed by chemical test. In Basmati, it seems that aroma is a complex trait and not as simple monogenic (3:1) as reported earlier. Aromatic and non-aromatic lines were almost common in three markers indicating association of markers with the trait and chromosome 8. The results revealed that these markers could be used for marker assisted selection and RIL population for mapping of aroma QTLs/genes.