Thursday, November 18, 2010

Rice as gems.

Clear rice grains or opaque ones? Consumers tend to gravitate towards varieties that are highly translucent, which command higher selling prices than those that are somewhat cloudy. In this sense, rice grains are comparable to gemstones. Rubies, emeralds, and sapphires of low clarity are not as expensive as those that sparkle, for instance. The opacity of the gemstones is caused by imperfections in the otherwise crystalline internal structure of these stones. 

In rice, imperfections of starch granules (the grains become porous) inside the grain likewise decrease the translucent quality of the grain. This is also known as CHALK. Xiangqian Zhao reported that grain chalkiness is affected by day and night environmental temperatures. As temperatures increase, so does the degree of chalkiness. Chalk is a detrimental property because it makes grains easier to break. Thus, given a high-yield paddy grain with lots of chalk, it is inevitable to have large losses post-harvest. In the light of rapid rice demand increase in a warming world, efforts are being made to understand the genetic factors affecting chalk to produce grains that are unaffected by environmental conditions.

On the other hand, with millions of grains going through quality evaluation programs, it's next to impossible to measure chalk manually within a logical timeframe. Imaging instruments that can take multiple photos of grains make life easier because these have algorithms that convert pixels into degree of chalkiness. Johan Van Asbrouck, a perfect example of a person thinking outside the box, presented new equipment that look into the physical traits of rice grains.

In his search for instruments that can measure important quality parameters of grains, he has attended conferences whose themes are outside the realms of agriculture. Machines initially developed for other fields are adapted for the seed industry.

Chalk is an economically important trait. Learning the genetics behind it and the efficient means of measuring it will help breeders reduce post-harvest losses and allow farmers to command higher prices to their produce.