Inheritance of Scent in American Long Grain Rice1

Abstract

Scented or aromatic rice (Oryza sativa L.) is highly valued in many areas of the world, but the development of high yielding scented cultivars has been limited by a lack of information on the inheritance of scent. Reciprocal crosses were made between the scented cultivar ‘Della’ and the nonscented cultivar ‘Dawn’ to study the inheritanceof scent in rice. Leaf tissue and seed samples from plants of the parental cultivars and of F1 and F2 progeny were placed in 0.3 mol L−1 KOH solution and rated for strength of aroma. The results indicated that the F1 plants were nonscented and the F2 populations segregated in a 3:1( nonscented:scented)r atio. Individual seeds from F1 plants were chewed and rated as scented or nonscented and the results showed that, due to xenia, the seeds from the heterozygous F1 plants also segregated in a 31 (nonscented:scented) ratio. Of 992 F2 seeds individually rated for scent, 748 were nonscented and 244 were scented. Chewing and rating individual F3 seeds of F2 plants confirmed the monogenic recessive inheritance of the scent character. It was found that scent could be detected in half of a single seed by chewing the distal portion while saving the portion of the seed with the embryo. Normal germination, with approximately 80% plant survival in the field, was observed when the embryo portions were planted. The scent character may be transferred into improved cultivars by several methods using the demonstrated ability to identify scented genotypes by chewing individual seeds.