In crop improvement programme, haploids are important because they
In crop improvement programme, haploids are very important because they form perfect homozygous which are helpful to get a pure line.
Haploid plants are preferred over diploids for mutation study because in haploids
Mutations are generally recessive so they are not expressed in their heterozygous condition. If plant is haploid then mutation can express themselves.
Most of our crop plants are
The polyploidy which occurs within a species & results due to multiplication of the same set of chromosomes is called autopolyploidy.
Haploid plant cultures are obtained from
All others are diploid but pollen grain is haploid.
The rotenone is
The rotenone is a natural insecticide with minimal or almost no side affects. It is an isoflavonoid extracted from the root of Derris.
One of the major difficulties in the biological control of insect pests is the
Biological control refers the use of living organisms like natural predators and parasites to reduce pest population and control diseases. However they may become pest as they can develop a preference to other diets.
The silkworm silk is the product of
The saliva from the salivary gland of silkworm is the component of silk and is produced by the larva of the silkworm (cocoon). The Chinese silkworm (B. mori) has been used in commercial silk production for centuries. The adult, which has a wingspan of about 2 in. (50 mm) and a thick, hairy body, lives only two or three days. The female lays 300–500 eggs. The pale, naked larvae are fed mulberry leaves until pupation begins, when they are about 3 in. (75 mm) long. They spin a cocoon of one continuous white or yellow silken thread, about 1,000 yards (900 m) long. The pupa is killed with hot air or steam to preserve the thread intact.
The long-term prospects for a truly human civilization depend in a large measure on
The long -term prospects for a truly human civilization depend in a large measure on control of human diseases.
Pasteurization of milk involve heating for
Pasteurization of milk is a method of partial sterilization by heating milk at 60 – 70°C for 30 min.
The earliest animal to have been domesticated by man was most likely the
Dog was the first animal to be domesticated by man.
Which one of the following is an exotic Indian fish ?
Catla catla and Labeo rohita are the two Indian major carps whereas Heteropneustes is a catfish. Cyprinus is the exotic breed.
Suppression of reproduction of one type of organism by utilizing some features of its biology or physiology to destroy it or by use of another organism is known as
Suppression of reproduction of one type of organism by utilizing some features of its biology or physiology to destroy it or by use of another organism is known as biological control.
Of the world’s top five crops in terms of annual production
The top five crops are : Potato (which belongs to the family Solanaceae) and Wheat, Rice, Corn, Barley (which belongs to the family Poaceae).
Which of the following has been recently used for increasing productivity of super milk cows?
In superovulation, a high milk yielding cow is induced to shed 4–6 eggs (instead of one) every 6–8 weeks (instead of 20–21 days). The superovulated donor is artificially inseminated with semen from a quality bull. The embryos developing from the eggs so fertilised are flushed out. These good quality embryos are now transfered to surrogate mother for delivery.
In the silk worm, if no juvenile hormone (JH) is present when it moults, it will
The presence of juvenile hormone is necessary for metamorphosis to adult.
The pH of honey ranges from 3.4 to 6.1, average being 3.9.
The reason why vegetatively reproducing crop plants are best suited for maintaining hybrid vigour is that
In vegetative reproduction the same genotype can be propagated from one generation to the next.
Lathyrism which is caused by consumption of Khesari dal is a disease characterised by
Lathyrism which is caused by consumption of Khesari dal is a disease characterised by gross skeletal deformation and thinning of collagen fibres and fibrils.
Biological control component is central to advanced agricultural production. Which of the following is used as a third generation pesticide?
Inorganic substances, oils, plant extracts used as insecticides are called first generation pesticides.
Synthetic organic compounds are known as second generation pesticides. Insect hormones are third generation pesticides.
Pheromones are the chemical substances which when released into an animal's surroundings, influence the behaviour or development of other individuals of the same species.
Insect hormone analogues help in trapping the insects by confusing them as they mimic the odour of pheromones.
Which of the following pesticides is an acetylcholinesterase inhibitor?
Malathionis an organophosphate parasympathomimetic which binds irreversibly to cholinesterase. Malathion is an insecticide of relatively low human toxicity.However, malathion breaks down into malaoxon, which is 60 times more toxic than malathion. For this reason, if malathion is used or somehow enters an indoor environment, as it breaks down into malaoxon, it can seriously and chronically poison the occupants living or working in this environmnent.
Malathion present in untreated water is converted to malaoxon during the chlorination phase of water treatment, so malathion should not be used in waters that may be used as a source for drinking water, or any upstream waters.
Which one among the following chemicals is used for causing defoliation of forest trees?
2, 4-Dichlorophenoxy acetic acid is used for causing defoliation of forest trees. 2, 4-D or 2, 4 Dichlorophenoxy acetic acid is an auxin hormone. It stimulates the growth activities of the cells of the root due to which roots get destroyed and thus plants finally destroys. 2, 4-D is used as a defoliant for broad leaved dicots.
What is Agent Orange?
Agent orange has equal parts of 2, 4-D and 2, 4, 5-T and is found to contain highly poisonous chemical dioxin as impurities.
Which one of the following insecticides is more stable in the environment?
DDT cannot be further metabolized into any stable by product.
The first transgenic crop was
The first transgenic crop was tobacco developed in USA in 1986, it was herbicide resistant.
The new varieties of plants are produced by
Selection is picking up only those plants for reproduction which have desired qualities. Hybridization is crossing of two or more types of plants for bringing their traits together in the progeny. Introduction is taking a plant or a new variety from an area where it grows naturally to a region where it does not occur before.