Identification of a Genetic Locus for the Shattering Trait in Weedy Rice

Crop domestication is the process by which humans shape the evolution of plants to suit their needs. Through artificial selection, humans have had the distinct ability to mold the characteristics of plants to create numerous crop varieties that provide humans with food. Traits selected for include greater yields, larger fruits and seeds, and in cereal crops, a loss of the seed dispersing mechanism. However, in the process of inventing agriculture, humans also created the new environment of cultivated fields that became available for opportunistic plants and animals, and thus the evolution of domesticated plants was accompanied by the evolution of agricultural weeds. A particularly problematic agricultural weed is weedy rice, which invades rice crop fields around the world and decreases crop yields. Weedy rice is able to persist and grow in abundance because unlike cultivated rice, weedy rice shatters, or drops its seeds to the ground. Seeds lost to shattering remain in the soil and sprout in the next growing season, further infesting crop fields. There is little known about how the shattering trait is genetically controlled, however previous research has shown the locus to be within a region of chromosome 2 that is 400 kb in length. It is possible to narrow down the region and potentially identify the locus through the use of a method known as Quantitative Trait Locus (QTL) mapping. In addition to supplementing knowledge of agricultural evolutionary mechanisms, determination of the shattering locus could ultimately allow for eradication of weedy rice and increased crop production.