- The process of developing a hybrid variety by crossing two different inbred lines of plants is known as:
a) Apomixis
b) Pedigree breeding
c) Hybrid breeding
d) Mutation breeding
Answer: c) Hybrid breeding
Explanation:
Hybrid breeding involves crossing two genetically distinct inbred lines to produce a hybrid variety with desirable traits such as high yield, disease resistance, or environmental tolerance. This method is commonly used for crops like maize and rice.
- Which of the following crops is known for its nitrogen-fixing capability through symbiotic association with Rhizobium bacteria?
a) Wheat
b) Rice
c) Legumes
d) Maize
Answer: c) Legumes
Explanation:
Leguminous plants form a symbiotic association with Rhizobium bacteria, which live in their root nodules. These bacteria convert atmospheric nitrogen into a form that the plants can absorb, thus enriching the soil with nitrogen.
- In aquaculture, which of the following is commonly cultured for pearls?
a) Shrimp
b) Oysters
c) Tilapia
d) Carp
Answer: b) Oysters
Explanation:
Oysters are commonly cultured in aquaculture for the production of pearls. The process involves inserting a small irritant into the oyster, which then secretes layers of nacre around it to form a pearl.
- Which one of the following is a high-yielding, disease-resistant variety of wheat developed in India during the Green Revolution?
a) Sonalika
b) Pusa 1121
c) IR-36
d) Norin-10
Answer: a) Sonalika
Explanation:
Sonalika is a high-yielding, disease-resistant variety of wheat developed during the Green Revolution in India. It contributed to the significant increase in wheat production during this period.
- The term ‘inbreeding depression’ refers to:
a) Reduced growth and productivity in inbred populations
b) Increased resistance to diseases in hybrids
c) Enhanced fertility in crossbred animals
d) Increased genetic diversity in inbred populations
Answer: a) Reduced growth and productivity in inbred populations
Explanation:
Inbreeding depression is the reduced biological fitness and productivity seen in populations due to inbreeding. It occurs because inbreeding increases the chances of homozygosity for deleterious alleles, leading to weaker offspring.
- The use of which of the following organisms in agriculture can help reduce the use of chemical fertilizers?
a) Earthworms
b) Rhizobium
c) Aphids
d) Termites
Answer: b) Rhizobium
Explanation:
Rhizobium is a nitrogen-fixing bacterium that forms symbiotic associations with leguminous plants. It helps convert atmospheric nitrogen into a form that plants can use, reducing the need for chemical fertilizers.
- Which of the following refers to the breeding of fish for commercial purposes?
a) Pisciculture
b) Horticulture
c) Apiculture
d) Sericulture
Answer: a) Pisciculture
Explanation:
Pisciculture, also known as fish farming, involves the breeding, rearing, and harvesting of fish in ponds, tanks, or controlled environments for commercial purposes.
- In the production of biofortified crops, which nutrient is increased in the rice variety known as ‘Golden Rice’?
a) Iron
b) Protein
c) Vitamin A
d) Calcium
Answer: c) Vitamin A
Explanation:
Golden Rice is genetically engineered to produce beta-carotene, a precursor of Vitamin A. This biofortified crop aims to combat Vitamin A deficiency, particularly in populations where rice is a staple food.
- Which of the following statements about hybrid varieties of crops is TRUE?
a) They show reduced yields compared to traditional varieties
b) They are more susceptible to diseases
c) They exhibit heterosis, leading to higher productivity
d) They require fewer inputs than local varieties
Answer: c) They exhibit heterosis, leading to higher productivity
Explanation:
Hybrid varieties of crops often show heterosis or hybrid vigor, resulting in improved traits such as higher yield, better resistance to diseases, and faster growth when compared to their parental varieties.
- Which of the following is the primary aim of mutation breeding in plants?
a) Introducing genetically modified genes
b) Developing disease-resistant varieties
c) Increasing the use of chemical fertilizers
d) Enhancing the water absorption of crops
Answer: b) Developing disease-resistant varieties
Explanation:
Mutation breeding involves exposing plants to chemicals or radiation to induce mutations. The goal is to develop new traits, such as disease resistance, which can help improve crop productivity and sustainability.
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