Researchers from Myanmar and Thailand have a paper in Field Crops Research ((Yi, M., Nwe, K., Vanavichit, A., Chai-arree, W., & Toojinda, T. (2009). Marker assisted backcross breeding to improve cooking quality traits in Myanmar rice cultivar Manawthukha. Field Crops Research. DOI: 10.1016/j.fcr.2009.05.006)) describing how they managed to get the prized gene for fragrance into a local rice variety which smelled, well, ordinary.
They started out with Manawthukha, a very well-liked but alas non-fragrant variety from Myanmar, and Basmati, which of course is the most famous of the fragrant rices, due to the badh2 allele. They did four cycles of back-crossing the latter with the former, always using progeny in which they could detect the DNA marker for the Basmati allele, and finally selfed the result. They then looked again for the tell-tale badh2 allele using molecular tools, hoping to find it in its homozygous state. Which they did, in 12 lines. Agronomic evaluation of these proved that they behaved essentially like Manawthukha, but were also nice and fragrant. QED. The authors say that the use of DNA markers to identify the gene for fragrancy right from the early cycles of selection considerably sped up the whole process of getting it into the Manawthukha genome.
Which sounds like a pretty good result. But I ran the paper past a rice expert of my acquaintance and he had an interesting question. Why did…
…Thai scientists collaborating with Myanmar choose to source the fragrance gene from Basmati, not from their own Khao Dawk Mali or other Thai aromatic varieties, nor from Myanmar’s own range of aromatic varieties? The alleles are identical in Basmati, Khao Dawk Mali and most of the Myanmar aromatics.
Any ideas?
But there’s more.
Some of the Myanmar aromatic varieties get their fragrance from a different gene, and one of them has twice the concentration of the main aromatic compound. Does that variety have both genes?
Good question. And no doubt there are people working on that. But I wonder whether other national programmes will be wanting to use that doubly fragrant Myanmar variety in their own efforts to have their own fragrant rice.
