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Asian rice (*Oryza sativa*) was first domesticated in India approximately 13,500 to 8,200 years ago.
Answer: False
Asian rice (*Oryza sativa*) was first domesticated in China, not India, approximately 13,500 to 8,200 years ago.
Long-grain rice varieties, such as Basmati, typically have a high amylose content, resulting in a dry and fluffy texture after cooking.
Answer: True
The higher amylose content in long-grain rice varieties like Basmati contributes to their characteristic dry and fluffy texture upon cooking, as opposed to the stickier texture of high-amylopectin varieties.
The entire growth cycle of a rice plant from seed to harvest typically takes about one year.
Answer: False
The entire growth cycle of a rice plant from seed to harvest typically takes approximately six months.
Rice plants reproduce through cross-pollination, requiring pollen from a different plant for fertilization.
Answer: False
Rice plants produce self-fertile flowers, meaning they can reproduce through self-pollination without requiring pollen from a different plant.
Genetic evidence suggests that *Oryza sativa* underwent multiple independent domestication events across Asia.
Answer: False
Genetic evidence, particularly the identical nonshattering allele in *indica* and *japonica* cultivars, suggests that *Oryza sativa* originated from a single domestication event in China.
Which of the following is the primary species of Asian rice?
Answer: *Oryza sativa*
The primary species of Asian rice, which is a staple food for over half of the world's population, is *Oryza sativa*.
Approximately how many years ago was Asian rice (*Oryza sativa*) first domesticated in China?
Answer: 13,500 to 8,200 years ago
Asian rice (*Oryza sativa*) was first domesticated in China during the period of approximately 13,500 to 8,200 years ago.
What characteristic is typically associated with long-grain rice varieties like Basmati and Jasmine?
Answer: Dry and fluffy, stays intact
Long-grain rice varieties such as Basmati and Jasmine are characterized by a higher amylose content, which results in a dry, fluffy texture where individual grains remain separate after cooking.
What is the approximate duration of the entire growth cycle of a rice plant from seed to harvest?
Answer: Six months
The complete growth cycle of a rice plant, from the initial seeding to the final harvest, typically spans approximately six months.
Genetic evidence suggests that *Oryza sativa* originated from a single domestication event in China from which wild rice species?
Answer: *Oryza rufipogon*
Genetic studies indicate that *Oryza sativa* emerged from a single domestication event in China, with the wild rice species *Oryza rufipogon* identified as its progenitor.
In 2023, rice was the second-largest crop globally by production volume, following sugarcane.
Answer: False
In 2023, rice was the third-largest crop globally by production volume, following sugarcane and maize.
Over 50% of global rice production is traded internationally, indicating a highly globalized market.
Answer: False
Only about 8% of global rice production is traded internationally, indicating a relatively localized market compared to other commodities.
Before the American War of Independence, rice was the most valuable export commodity in British North America.
Answer: False
Before the American War of Independence, rice was the fourth most valuable export commodity in British North America, surpassed by tobacco, wheat, and fish.
In 2023, India and China combined accounted for over half of the world's total rice production.
Answer: True
In 2023, India and China each produced 207 million tonnes of rice, collectively accounting for 52% of the total global production.
Global per capita rice consumption has generally increased in the 21st century due to population growth.
Answer: False
Globally, per capita rice consumption has decreased in the 21st century, with an exception in Sub-Saharan Africa, as diets shift away from grain towards more meat in many regions.
In 2023, what was the global production of rice in tons?
Answer: 800 million tons
Global rice production in 2023 reached 800 million tons, positioning it as the third-largest crop by volume worldwide.
What percentage of global rice production is typically traded internationally?
Answer: About 8%
A relatively small proportion, approximately 8%, of the total global rice production is traded internationally, with the majority consumed in producing regions.
By the start of the American War of Independence, rice was ranked as the fourth most valuable export commodity in British North America, after which three commodities?
Answer: Tobacco, wheat, and fish
Prior to the American War of Independence, rice held significant economic importance in British North America, ranking behind only tobacco, wheat, and fish in export value.
Which two countries were the largest producers of rice in 2023, each contributing 207 million tonnes?
Answer: India and China
In 2023, India and China were the leading global rice producers, each contributing 207 million tonnes and collectively accounting for over half of the world's total output.
Which region is an exception to the global trend of decreasing per capita rice consumption in the 21st century?
Answer: Sub-Saharan Africa
While global per capita rice consumption has generally declined in the 21st century, Sub-Saharan Africa stands as a notable exception, experiencing an increase in both rice consumption per person and overall population.
Poor transport and inadequate storage facilities are significant contributors to post-harvest rice losses in developing nations.
Answer: True
Post-harvest losses in developing nations are substantially influenced by factors such as inefficient transport infrastructure and insufficient storage capabilities, as exemplified by Nigeria's quarter-crop loss.
Parboiled rice is rice that has been partially cooked by boiling before milling, which helps retain nutrients.
Answer: False
Parboiled rice undergoes a steaming process before milling, not boiling, which helps transfer and retain nutrients within the grain.
Direct seeding requires less seed per hectare compared to transplanting methods in rice cultivation.
Answer: False
Direct seeding typically requires a higher quantity of grain (60-80 kg/hectare) compared to transplanting methods (around 40 kg/hectare).
The 'alternate wetting and drying' technique in rice cultivation uses more water than continuous flooding to maximize yields.
Answer: False
The 'alternate wetting and drying' technique is designed to use less water than continuous flooding by allowing the water level to drop significantly before re-flooding.
'Paddy' refers to milled rice that has been cleaned and dried, ready for consumption.
Answer: False
'Paddy' refers to unmilled rice, which still retains its husk and other outer layers.
Drying rice grain immediately after harvest is crucial to prevent damage from mould fungi.
Answer: True
Reducing the moisture content of rice grain to 20–25% as quickly as possible after harvest is essential to inhibit the growth of mould fungi and preserve grain quality.
Yuan Longping set a world record for rice yield using traditional farming methods without hybrid rice.
Answer: False
Yuan Longping achieved his world record for rice yield in 1999 by utilizing specially developed hybrid rice and the System of Rice Intensification (SRI), not solely traditional methods.
Which of the following is NOT listed as a factor contributing to post-harvest losses of rice in developing nations?
Answer: Excessive international trade
Post-harvest losses in developing nations are primarily attributed to issues such as poor transport, inadequate storage facilities, and pest infestations, not excessive international trade.
What is the primary advantage of parboiled rice?
Answer: It retains more vitamins and minerals after milling.
The steaming process involved in parboiling rice before milling helps to transfer and lock in vitamins and minerals from the husk and bran into the endosperm, thus enhancing its nutritional retention after milling.
What is the primary purpose of drying rice grain immediately after harvest?
Answer: To prevent damage from mould fungi
Immediate drying of rice grain after harvest is critical to reduce its moisture content, thereby preventing the proliferation of mould fungi that can significantly degrade grain quality and lead to spoilage.
What does the term 'paddy' refer to in the context of rice harvesting?
Answer: Unmilled rice
In the context of rice harvesting, 'paddy' specifically denotes unmilled rice, which still retains its protective outer husk.
What method did Yuan Longping use to achieve his world record for rice yield in 1999?
Answer: Specially developed hybrid rice and the System of Rice Intensification (SRI)
Yuan Longping's record-breaking rice yield in 1999 was achieved through the strategic combination of specially developed hybrid rice varieties and the System of Rice Intensification (SRI) cultivation practices.
Rice is a complete protein, providing all essential amino acids required for good health in sufficient amounts.
Answer: False
Rice is not considered a complete protein because it lacks sufficient amounts of all essential amino acids required for good health.
Cooked white rice contains high levels of fat and provides a significant portion of daily caloric intake from fat.
Answer: False
Cooked white rice contains negligible fat, with its 130 calories per 100-gram serving primarily derived from carbohydrates and protein.
The World Health Organization strongly recommends fortifying rice with iron to address nutritional deficiencies.
Answer: True
In 2018, the World Health Organization issued a strong recommendation for fortifying rice with iron, alongside conditional recommendations for vitamin A and folic acid, to combat widespread nutritional deficiencies.
Golden rice is a genetically engineered variety designed to produce vitamin C, aiming to combat scurvy.
Answer: False
Golden rice is genetically engineered to synthesize beta-carotene, a precursor of vitamin A, with the aim of combating Vitamin A deficiency, not scurvy.
The International Rice Research Institute (IRRI) is primarily focused on developing new rice recipes rather than conserving genetic resources.
Answer: False
The International Rice Research Institute (IRRI) plays a critical role in conserving rice genetic resources through its International Rice Genebank, which houses over 100,000 rice varieties.
NERICA rice cultivars were developed specifically for cultivation in Asia to improve food security in that region.
Answer: False
NERICA, or 'New Rice for Africa,' cultivars were specifically developed for cultivation in Africa to improve food security and alleviate poverty in Sub-Saharan Africa.
The complete genome of rice was first sequenced in 2005, making it the first crop plant to achieve this status.
Answer: True
The sequencing of the complete rice genome in 2005 marked a significant milestone, establishing it as the first crop plant to have its entire genetic code mapped.
Green Revolution rice varieties were bred with tall, slender stems to allow for easier manual harvesting.
Answer: False
Green Revolution rice varieties were specifically bred to have short, strong stems to prevent lodging when heavy applications of fertilizer were used, thereby increasing productivity.
Ventria Bioscience has genetically modified rice to express proteins found in breast milk, which can be used in oral rehydration solutions.
Answer: True
Ventria Bioscience has successfully engineered rice to produce human proteins like lactoferrin and lysozyme, which are valuable components for oral rehydration solutions to treat diarrheal diseases.
C4 rice is a commercially available variety known for its enhanced drought resistance.
Answer: False
C4 rice is a proposed variety currently under development, aiming for more efficient photosynthesis, and is not yet commercially available or primarily known for drought resistance.
Why is rice not considered a complete protein?
Answer: It lacks sufficient amounts of all essential amino acids.
Rice is classified as an incomplete protein because it does not contain all nine essential amino acids in the proportions necessary for optimal human health.
What is the approximate energy content of a 100-gram serving of cooked white rice?
Answer: 130 calories
A standard 100-gram serving of cooked white rice provides approximately 130 calories of food energy, primarily from carbohydrates.
The World Health Organization (WHO) strongly recommended fortification of rice with which micronutrient in 2018?
Answer: Iron
In 2018, the World Health Organization issued a strong recommendation for the fortification of rice with iron as a key strategy to combat widespread nutritional deficiencies.
What is the intended purpose of Golden rice?
Answer: To synthesize beta-carotene for Vitamin A deficiency
Golden rice was genetically engineered with the specific purpose of synthesizing beta-carotene in its endosperm, serving as a precursor to vitamin A to address Vitamin A deficiency in vulnerable populations.
What is the primary role of the International Rice Research Institute (IRRI) regarding rice varieties?
Answer: To conserve rice genetic resources in its Genebank
The International Rice Research Institute (IRRI) plays a crucial role in global food security by maintaining the International Rice Genebank, which is dedicated to conserving the vast genetic diversity of rice varieties.
What does NERICA rice stand for, and what is its significance?
Answer: New Rice for Africa; high-yield cultivars for food security in Africa.
NERICA, an acronym for 'New Rice for Africa,' represents a significant agricultural innovation, comprising high-yield rice cultivars specifically developed to enhance food security and alleviate poverty across Sub-Saharan Africa.
When was the complete genome of rice first sequenced, making it the first crop plant to achieve this status?
Answer: 2005
The complete genome of rice was first sequenced in 2005, marking a pioneering achievement as it was the first crop plant to have its entire genetic blueprint mapped.
What was the primary characteristic bred into Green Revolution rice varieties to make them more productive?
Answer: Short, strong stems
Green Revolution rice varieties were selectively bred for short, strong stems, a trait that prevented lodging (falling over) and allowed them to support heavier grain heads when fertilized, thereby significantly increasing yields.
Ventria Bioscience genetically modified rice to express proteins typically found in breast milk, such as lactoferrin and lysozyme. What is a potential benefit of this modified rice?
Answer: It can be used in oral rehydration solutions to treat diarrheal diseases.
The genetically modified rice expressing human proteins like lactoferrin and lysozyme offers a promising application in oral rehydration solutions, which can be vital in treating diarrheal diseases and addressing anemia.
Rice blast is a disease caused by a bacterium, *Xanthomonas oryzae* pv. *oryzae*, and is one of the most serious diseases affecting rice.
Answer: False
Rice blast is caused by the fungus *Magnaporthe grisea*. Bacterial leaf streak, caused by *Xanthomonas oryzae* pv. *oryzae*, is a separate serious disease.
Rice paddies contribute significantly to global greenhouse gas emissions, primarily through the release of carbon dioxide.
Answer: False
Rice paddies contribute significantly to global greenhouse gas emissions, but primarily through the release of methane, not carbon dioxide, due to anaerobic fermentation in waterlogged soils.
One study projects a decrease in global rice yield by about 3.2% for every 1°C increase in global average temperature.
Answer: True
Various studies on climate change impacts on agriculture project a decrease in global rice yield, with one specific study estimating a reduction of approximately 3.2% for each 1°C rise in global average temperature.
Rice flowers can still yield grain even if exposed to temperatures of 35°C or more for several hours.
Answer: False
Rice flowers are highly sensitive to heat; they cannot yield grain if exposed to temperatures of 35°C or more for over an hour.
Unnecessary pesticide applications in rice farming can sometimes lead to a resurgence of pest populations.
Answer: True
Excessive or unnecessary pesticide use can disrupt the natural balance by destroying beneficial insects, thereby leading to a resurgence of pest populations like the brown planthopper.
Standard rice varieties can survive stagnant flooding for several months without significant yield loss.
Answer: False
Standard rice varieties are highly susceptible to stagnant flooding and typically cannot survive for more than about a week, leading to substantial yield losses.
The Swarna Sub1 cultivar and 'scuba rice' both improve flood tolerance in rice by enabling the plant to consume carbohydrates efficiently during submergence.
Answer: True
The Swarna Sub1 cultivar and 'scuba rice' (which incorporates the Sub1A transgene) enhance flood tolerance by allowing the rice plant to manage its carbohydrate reserves effectively during periods of submergence, thus improving survival.
The *DRO1* gene, when inserted into commercial rice varieties, helps create deeper root systems that improve drought tolerance.
Answer: True
Research has demonstrated that the insertion of the *DRO1* gene into commercial rice varieties promotes the development of deeper root systems, which significantly enhances the plant's ability to access water and tolerate moderate drought conditions.
Rice is highly tolerant to cold temperatures, thriving in sustained temperatures below 12°C.
Answer: False
Rice is sensitive to cold temperatures; sustained temperatures below 12°C can severely reduce growth, harm germination and seedling development, and increase susceptibility to diseases like rice blast.
Genetic engineering can reduce methane emissions from rice paddies by shifting biomass production from roots to shoots.
Answer: True
By introducing the barley gene *SUSIBA2*, genetic engineering can redirect biomass production in rice plants from roots to shoots, thereby decreasing the population of methanogenic bacteria in the anaerobic soil and significantly reducing methane emissions.
Which two diseases are perennially considered the most serious threats to rice worldwide?
Answer: Rice blast and bacterial leaf streak
Rice blast, caused by *Magnaporthe grisea*, and bacterial leaf streak, caused by *Xanthomonas oryzae* pv. *oryzae*, are consistently identified as the two most significant disease threats to global rice production.
Which of the following is an abiotic factor influencing rice growth?
Answer: Soil type
Abiotic factors are non-living chemical and physical parts of the environment that affect living organisms. Among the choices, soil type is an abiotic factor influencing rice growth, alongside water, temperature, day length, and sunlight intensity.
What percentage of total global greenhouse gas emissions was attributed to rice cultivation in 2022?
Answer: 1.2%
In 2022, rice cultivation was estimated to contribute 1.2% of total global greenhouse gas emissions, representing a significant portion of agricultural emissions.
Why do rice fields subject to long-term flooding release methane?
Answer: The waterlogged soil inhibits atmospheric oxygen absorption, leading to anaerobic fermentation.
Long-term flooding in rice fields creates anaerobic conditions in the soil, which inhibits oxygen absorption and promotes the anaerobic fermentation of organic matter by methanogenic bacteria, leading to methane release.
According to one study, what is the projected decrease in global rice yield for every 1°C increase in global average temperature?
Answer: 3.2%
One study projects a significant impact of climate change on rice production, estimating a decrease in global rice yield of approximately 3.2% for every 1°C rise in global average temperature.
What is one of the four principles of sustainable pest management in rice cultivation?
Answer: Promoting biodiversity
Promoting biodiversity is a fundamental principle of sustainable pest management in rice cultivation, as it helps maintain natural predator-prey relationships and reduces reliance on chemical interventions.
Why can unnecessary pesticide applications be counterproductive in rice pest management?
Answer: They can induce a resurgence of pest populations by destroying beneficial insects.
Unnecessary pesticide applications can disrupt the ecological balance in rice paddies by eliminating beneficial insects that naturally control pest populations, thereby leading to a resurgence of the target pests.
What is the maximum duration standard rice varieties can typically survive stagnant flooding?
Answer: About a week
Standard rice varieties are highly vulnerable to stagnant flooding and typically cannot survive submergence for more than approximately one week, leading to severe crop losses.
How does the *DRO1* gene, when inserted into commercial rice varieties, improve drought tolerance?
Answer: It creates deeper root systems for better nutrient access.
The *DRO1* gene enhances drought tolerance in rice by promoting the development of deeper root systems, which allows the plant to access water and nutrients from deeper soil layers during periods of water scarcity.
What is a primary reason soil salinity severely threatens rice crop productivity?
Answer: It affects plant physiology during early growth stages.
Soil salinity poses a severe threat to rice productivity primarily by negatively impacting plant physiology, particularly during the critical early growth stages, which can lead to reduced yields or crop failure.
What is the effect of sustained cold temperatures (below 12°C) on rice plants?
Answer: It reduces growth, harms germination, and encourages rice blast.
Sustained cold temperatures below 12°C are detrimental to rice plants, leading to inhibited growth, impaired germination and seedling development, and increased susceptibility to diseases such as rice blast, ultimately reducing yield.
How can genetic engineering reduce methane emissions from rice paddies?
Answer: By introducing a gene that shifts biomass production from roots to shoots, decreasing methanogenic bacteria.
Genetic engineering, specifically by introducing the *SUSIBA2* gene, can reduce methane emissions from rice paddies by altering the plant's biomass allocation to favor shoots over roots, thereby limiting the substrate for methanogenic bacteria in the soil.
In Hindu wedding ceremonies, rice is thrown into the sacred fire to symbolize fertility, prosperity, and purity.
Answer: True
The act of throwing rice into the sacred fire during Hindu wedding ceremonies is a deeply symbolic gesture, representing wishes for the couple's fertility, prosperity, and purity in their married life.
The Royal Ploughing Ceremony in some Asian countries marks the end of the rice harvest season.
Answer: False
The Royal Ploughing Ceremony, observed in countries like Nepal and Cambodia, traditionally marks the *beginning* of the rice planting season, seeking blessings for a successful harvest.
The 9th-century Borobudur bas-relief provides historical evidence of rice cultivation, storage, and pest challenges in ancient Indonesia.
Answer: True
The bas-reliefs at Borobudur from the 9th century offer valuable historical insights into ancient Indonesian agricultural practices, clearly depicting rice cultivation, storage methods, and the perennial challenge of pest infestations.
In Hindu wedding ceremonies, what do rice grains thrown into the sacred fire symbolize?
Answer: Fertility, prosperity, and purity
The act of throwing rice grains into the sacred fire during Hindu wedding ceremonies is a profound symbolic gesture, representing wishes for the couple's fertility, prosperity, and purity in their marital life.
What cultural ceremony marks the beginning of the rice planting season in countries like Nepal and Cambodia?
Answer: The Royal Ploughing Ceremony
The Royal Ploughing Ceremony is a traditional cultural event in several Asian countries, including Nepal and Cambodia, that ceremonially inaugurates the rice planting season, seeking auspicious blessings for a bountiful harvest.