In agriculture, shattering is the dispersal of a crop's seeds upon their becoming ripe. From an agricultural perspective this is generally an undesirable process, and in the history of crop domestication several important advances have involved a
mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, m ...
in a crop plant that reduced shattering—instead of the seeds being dispersed as soon as they were ripe, the mutant plants retained the seeds for longer, which made harvesting much more effective. Non-shattering phenotype is one of the prerequisites for plant breeding especially when introgressing valuable traits from wild varieties of domesticated crops.
A particularly important mutation that was selected very early in the history of agriculture removed the "brittle rachis" problem from wheat. A ripe head ("ear") of wild-type wheat is easily shattered into dispersal units when touched, or blown by the wind, because during ripening a series of
abscission layers forms that divides the
rachis into short segments, each attached to a single
spikelet (which contains 2–3 grains along with
chaff).
A different class of shattering mechanisms involves
dehiscence of the mature fruit, which releases the seeds.
Current research priorities to understand the genetics of shattering include the following crops:
*
Barley
Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Globally 70% of barley ...
*
Buckwheat
*
Grain Amaranth
* Oilseed rape (''
Brassica napus'')
Sesame and
canola are harvested before the seed is fully mature, so that the pods do not split and drop the seeds.
References
{{Wheat
History of agriculture
Mutation