Lecture 15: Crop evolution Flashcards
What are the key dates of agricultural improvements
1700 seed drill
1850 rotations
1920 fertilisers and plant breeding, Haber Bosch
1950s better agrochemicals
1980s more agrochemical diversity
What is cultivation?
growing plants out of natural range
what is domestication?
choosing plants to eat
what is plant breeding?
crossing plants
What traits are desirable in crops
loss of seed dispersal
loss of seed dormancy
perennial to annual
loss of fruit/seed (non crop) production
increase in size of crop part
loss of biterness
What is an ear
group of seeds on maize, wheat, barley where grains are attached to rachis
what is a rachi
wobbly stem
what is shattering
grain falls of rachis
what is tillering
wastes energy on non-beneficial tillers
History of maize crops
teosinite ancestor domesticated on ear architecture
slow change in DNA over time
multiple hybridisation events led to introgression
How many copies of each gene in wheat
Six (hexaploid)
Einkorn wheat
diploid
used for fodder and in inhospitable areas
Durum wheat
quadraploid free-threshing and hard grains
used for bread
Emmer wehat
quadraploid but hulled so needs milling
Bread wheat
hexaploid
free-threshing
soft grains
tough rachis so less shattering
larger leaves
reduced tillering
