Aroma inheritance was studied in a cross between Basmati 370 from Pakistan and India as an aromatic rice and IR36 from IRRI, an improved non-aromatic cultivar. F 1, F2, and the progenies were analyzed [40 seeds (F3) from each plant] and the genotype of F2 plants being determined accordingly. Pattern of F2 segregation for non aroma was 3: 1 [19 homozygous non scented, 68 heterozygous and 36 homozygous scented plants (X2=1.l95)], indicating that aroma is controlled by a recessive gene in these cultivars.
This result was confirmed by analyzing F2 population with RAPD marker (AG8-AR) that is tightly linked to the aroma. The pattern of F2 segregation linked to AG8-AR marker was 3: 1 [32 aromatic bands and 12 non aromatic bands (X2=0.12)]. A number of 1236 single seeds analyzed in F2 progenies, showed that 524 were non aromatic (IR 36 type), 320 as slightly aromatic, 133 seeds moderately aromatic (intermediate aromatic) and 259 as strong aromatic (Basmati 370 type). In this case of evaluation aroma is categorized into four classes (non, slight, moderate and strongly aromatic) instead of in two classes (non aromatic and aromatic). The results indicate that aroma is controlled by at least two genes.
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