Rice fragrance origins revealed

Highly valued rice fragrance has origins in basmati rice, study finds

03-Sep-2009 - USA

A new Cornell study reports that the gene that gives rice its highly valued fragrance stems from an ancestor of basmati rice and dispels other long-held assumptions about the origins of basmati.

Rice is classified into two major varietal groups: Japonica and Indica, both of which were grown in China some 8,000 years ago and are believed to have originated from there. The new study, published in the Proceedings of the National Academy of Sciences, confirms that basmati rice, long assumed to be an Indica variety, is actually more closely related genetically to Japonica rice.

Basmati, which is endemic to northern India, Pakistan and Iran, has been falsely assumed to be in the Indica group due to its characteristic long, thin grains and because it is grown in India, where Indica varieties are widespread. Japonica varieties, which include sushi rice, are widely grown in East and Southeast Asia and tend to have shorter, stickier grains.

When the gene, called BADH2, loses its function through the natural process of mutation, rice becomes fragrant. This study reports eight novel mutations in BADH2 associated with fragrance and found that a previously discovered mutation, or allele, is shared by the vast majority of fragrant rice varieties today, including the fragrant Japonica varieties known as basmati and the fragrant Indica variety known as Thai jasmine.

Through genetic analysis of the DNA flanking BADH2, the researchers determined that the major fragrance allele originated in a Japonica-ancestor of basmati rice and was later transferred to Indica varieties, including Thai jasmine rice.

"People think that all rice [varieties] in India are from the Indica varietal group, but that's not true," said Susan McCouch, professor of plant breeding and genetics and the paper's senior author. Michael Kovach, a doctoral student in McCouch's lab, is the paper's first author.

The new study supports findings from a 2005 paper by McCouch that showed the close genetic relationship of basmati rice to the Japonica varietal group.

https://www.bionity.com/en/news/105626/rice-fragrance-origins-revealed.html