Lecture 4 - Rice Flashcards
what is rice
the seed of a semi-aquatic grass that thrives in tropical and sub-tropical climates
rice is the worlds _____ important grain cereal
most
around how much of the world’s population considers rice a staple food
more than half of the world’s population
what is the whole grain of rice with the husk called
paddy
how is the husk removed from rice
milling
food uses for rice
boiled rice, rice flakes, puffed rice, rice pudding, risotto, ground rice for confectionery
non-food uses for rice
rice powder, starch, sake, husks used animal feed, and a mix for concrete, rice oil for cooking, straw is used for roof
2 types of rice
sticky and basmati rice
top rice producing country in 2018
China
is irrigated, rainfed lowland, or upland rice the most common way of growing rice
irrigated
what ploidy is rice
diploid (2n=24), but triploid and tetraploid also exists
where is rice native too
SE Asia
rice was cultivated in China for _______ years
5000
what is the wild progenitor for rice
Oryza rufipogon
is rice freely tillering
yes
how tall is rice
50-150cm tall
how does rice pollinate
typically self pollinating with 0-4.5% outcrossing
what is the optimum germination temp for rice
30-35 C
types of grain shape for rice
extra long
long
medium
short
types of maturity in rice
very early (<110days), early (110-140days), late (150-170days), very late (>180days)
3 sub species of rice
javanica, japonica, indica
where is rice typically grown
subtropical and warm temperate climates
how many months do rice require and at what temp
need 4-6 months at 20-25C (minimum of 10C)
water requirements of lowland rice
800-2400mm of rain and cannot tolerate dessication
types of rice
hill rice, swamp rice, floating rice
hill rice
upland or dryland rice
needs good rains for 3-4 months
swamp rice
lowland rice
grown in irrigated or flooded areas
what does rice require in order to be cultivated
controlled flooding and draining of the land
floating rice
grown in areas of deep flooding (up to 5m or more)
how does planting of rice happen
transplants which are direct seeded in a nursery
how deep is manual flooding in rice cultivation
2-3 inches
why is fertilizer not really needed in rice cultivation
has blue-green algae that fixes N with Azotobacter
how can you tell when rice is ready to be harvested
18% to 23% moisture content
2 types of lowland rice cultivation
traditional system and mechanized system
traditional system of lowland rice cultivation
grown completely with hand labor by small holders with 1-5 acres
requires 400 person hours per acre to transplant seedlings and harvest each panicle by hand
mechanized system of lowland rice cultivation
seeded by airplane or machine
presoaked seed is in flooded 2.4-5cm field until plant grows. water level is then raised to 10-15cm
high fertilization and weed control
field is drained a week before grain is ripe
harvest using combine
how is rice harvested
rice grains are separated from stalks and dried
how is rice dried modernly
forced air blowers
how is rice traditionally dried
dried in the sun
what is the dried rice/paddy moisture content
12-14%
what does milling do to paddy rice
makes it consumable for humans
4 major part of rice
hull, bran, endosperm, germ
hull of rice
fibrous indigestible shell
bran of rice
outer layer of dehulled rice kernal
endosperm of rice
large interior, containing most nutrients
germ of rice
embryo of rice kernal containing most of the oil
milling steps of rice
hull removed
bran and germ are removed
white rice is sorted to remove broken kernals
most rice is enriched with thin coating of nutrients
types of rice by milling
paddy rice
whole grain rice (hull removed)
white rice (hull, bran, and germ removed)
main agency of rice improvement
international rice research institute in Los Banos, Philippines
what does SRI stand for
system of rice identification
what is SRI
special method of rice identification originally developed in Madagascar in 1983 that uses a combination of several practices and emphasize change
6 steps of SRI
- early transplanting
- Careful transplanting
- wide spacing
- weeding and aeration
- water management
- compost application
how does SRI improve effectiveness
reduce water, seed, and chemical fertilizer inputs while still increasing yield
how did rice production meet consumer preferences and environmental tolerance
hybrid rice
what is hybrid rice
first generation offspring between 2 genetically diverse parents
male sterility
a condition in which the pollen grain is unviable or cannot germinate and fertilize normally to set seeds
types of male sterility systems
cytoplasmic genetic male sterility
environment-sensitive genetic male sterility
chemically induced male sterility
who started hybrid rice research
china
what are some problems with hybrid rice
little diversity in genetic material
poor grain quality
seed production is difficult
cultivation requires additional input expense
super hybrid varieties in china yield _________
13.5t/ha
golden rice
rice that is high in b-carotene
