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Right choice is (C) The FEMALE WORM is circular

The best explanation: Root-knot of Brinjal and Tomato is caused by NEMATODE Meloidogyne incognita. The male worm is cylindrical and female worm is pear-shaped. INFECTED cells proliferate near the site of infection produces spherical to elliptical swellings called galls.

Correct choice is (b) False

Explanation: Measures used to control diseases caused by nematodes INCLUDE DISINFECTION of soil by steam, rotation of crops, FALLOWING, biological control agents, UNCONTAMINATED seeds, resistant varieties and SPRAYING crops with nematicides.

Correct option is (a) Yellowing of FOLIAGE

The EXPLANATION is: Non- characteristic above-ground symptoms of nematode disease include reduced GROWTH, yellowing of foliage, wilting and low-quality YIELD of the plant.

The correct choice is (c) Caused by Puccinia

To explain I WOULD say: LOOSE SMUT of wheat is a highly damaging smut DISEASE that is more common in humid areas. The disease is caused by Ustilago. It ALSO attacks Barley and a number of grasses.

Right ANSWER is (b) Fungi

Explanation: Witches broom is a characteristic symptom of DISEASES caused by fungi. The various symptoms of the fungal disease include necrosis, leaf spots, cankers, scabs, pustules, dieback, DAMPING off, BLIGHTS, rots, stunting, leaf curls, overgrowths, warts, GALLS, witches’ broom, wilt, rust, smut and mildew.

Right option is (a) Antibiotics

For EXPLANATION I would SAY: Fungal diseases can be controlled by roguing or REMOVAL of diseased PARTS, sanitation or DESTRUCTION of plant debris, resistant varieties, use of pathogen-free seeds, bio pesticides if available and spraying with fungicides like Bordeaux mixture.

Right choice is (a) True

The BEST explanation: Symptoms of fungal DISEASES may be localised i.e. RESTRICTED to an area of infection or MAYBE systemic i.e. spreading throughout the plant body.

Correct choice is (a) Two

Easy EXPLANATION: Disease-causing fungi are of two types, obligate and non-obligate parasites. Obligate parasites can grow and MULTIPLY only in the ASSOCIATION of their host PLANTS. Non-obligate parasites become parasitic only when they come in contact with a suitable host.

Right option is (d) Virus-free SEEDS

Explanation: Bacterial DISEASES in plants can be controlled by roguing of INFECTED plants, sanitation measures, use of HEALTHY disease-free seeds, chemical sprays, antibiotics, periodic sterilisation of soil and by growing resistant VARIETIES.

Correct choice is (b) Mosaic

To explain I would say: The symptoms of BACTERIAL DISEASE in plants include LOCAL lesions and necrosis, blights, rots, wilts, overgrowths, thickness and galls, STUNTING, scabs and CANKERS.

Correct option is (B) False

The best EXPLANATION: Bacteria spread from infected plants to HEALTHY plants by AIR, water, mechanical contact, insects, other animals and human beings. Some insects function as vectors in which bacteria can survive and multiply.

The correct choice is (b) Cutting leaves

Best EXPLANATION: Infection of MOSAIC virus can be overcome by using virus-free seeds, DELAYED planting, sowing resistant varieties, by removal of weeds and hosts of the virus, soil treatment with INSECTICIDES and FOLIAR spray to restrict vectors.

Right option is (b) Clostridium

Explanation: About 900 species of bacteria are plant PATHOGENS, e.g; species of Acidovorax, PSEUDOMONAS, Rhizobacter, Rhizomonas, Xanthomonas, Bacillus, Clostridium, Clavibacter, etc. Bacterial pathogens of plants MAY be obligate pathogens, facultative pathogens and facultative saprophytes.

Right option is (d) Blackening of leaflets

Easiest explanation: BEAN mosaic infected plants are stunted and bunchy. Their leaves show mottling, yellowing and MALFORMATIONS. Mosaic appears DUE to the OCCURRENCE of light and dark green areas with clearing or yellowing of veins. Seeds are small, MALFORMED or aborted.

Correct option is (a) Virus

The explanation is: BEAN Mosaic Disease is caused by mainly two viruses, Common Mosaic Virus and Yellow Mosaic Virus. It is a common disease of beans of all types like Soya bean, Mung bean, URD bean, FRENCH bean, Broad bean, WINGED bean, ETC.

Right option is (a) True

The explanation is: COMMON symptoms of viral diseases in plants are MOSAICS, local LESIONS, necrosis, ring spots, pitting, stunting, proliferation, leaf rolls, etc. VARIEGATION of flowers (flower breaking) produces unique DESIGNS.

Right choice is (b) ANTIBIOTICS

The explanation is: Pesticides and antibiotics are useless in CONTROLLING viral infections. Control is achieved through resistant varieties, USING healthy virus-free SEEDS, protection from INSECT vectors, sterilisation of agricultural implements and sanitation.

Right choice is (B) Meristem

Easiest explanation: Virus enters the healthy host through WOUNDS made MECHANICALLY or by vectors, infected FUNGAL SPORES and infected pollen. They enter the cells, multiply and reach phloem which helps in spreading the virus throughout the plant.

Correct choice is (c) Through meristem

The best I can explain: Virus infection SPREADS from either an infected plant or plant RESIDUE by agricultural implements, exuding sap of infected PLANTS, vegetative propagules, infected seeds or POLLEN, Aphids, MITES or other insect vectors, Nematodes and Fungal spores.

The correct OPTION is (b) Riboviruses

Explanation: Viruses that generally AFFECT plants are riboviruses with SSRNA genome. Viruses are obligate parasites which are NUCLEOPROTEIN entities consisting of DNA or RNA as the genetic material. 50% of the plants are rod-like.

Right choice is (c) Perfect flowering

Easy EXPLANATION: The common symptoms of plant diseases include Necrosis, Pustules, Pitting, ROTS, Leaf curls, EXCESSIVE GROWTH of tissues, Stunting, CHLOROSIS, Wilting, Mosaics, Root Galls, Damping-off and excessive root branching.

The correct answer is (b) Death of plant TISSUES

To explain: Chlorosis is the yellowing of green tissues or structures (especially LEAVES) due to either non-formation or destruction of chlorophyll. Chlorosis is quite common in the CASE of mineral deficiency. It ALSO occurs in response to FUNGAL, bacterial and viral infections.

The correct option is (c) DISTORTION of leaves

Explanation: Rots is the discolouration, softening and DEGENERATION of a succulent TISSUE due to fungal or BACTERIAL infection. It is of two types- Dry rot (Rot is WITHOUT an oozing) and Soft rot (Rot is accompanied by oozing).

The correct CHOICE is (a) Curling of leaves

Easiest explanation: Necrosis is the death of plant TISSUE or can be characterised by discolouration of areas on leaves, STEMS and roots. It is a common SYMPTOM in FUNGAL diseases but also occurs in bacterial and viral diseases.

The correct answer is (a) True

Explanation: Plant diseases are broadly classified into TWO categories, nonparasitic and parasitic. Nonparasitic diseases are non-transmissible and are caused by physiological DISORDERS due to defective heredity or UNFAVOURABLE environment. Parasitic diseases are transmissible diseases which are caused by various categories of PATHOGENS.

The correct option is (b) STUDYING the crop

To ELABORATE: Diseases reduce the total biomass of the crop by causing DAMAGE to leaf tissues, stunting effect, damage to reproductive structures LIKE flowers, fruits and seeds, killing of branches. This all RESULTS in the death of the plant.

The correct choice is (c) REDUCING the quantity of yield

Easy explanation: Various steps of the perpetuation of disease by the PATHOGEN are coming of a pathogen in contact with HOST plants, entry of the pathogen into the host through natural openings, WOUNDS or direct penetrations, the establishment of the pathogen inside the host, reproduction of pathogen, etc.

The correct OPTION is (d) Increases WATER pollution

To explain I would say: SCP can be used as a PROTEIN-rich supplement of human diet and can take off the pressure from the agricultural SYSTEM for increasing the protein content of food articles. It also increases the protein supply and use of organic wastes and industrial effluents helps in reducing ENVIRONMENTAL pollution.

The correct choice is (d) INCREASE the flowering period

To explain: Pathogens AFFECT the CROP yield by reducing the quantity of yield and reducing the quality of crop produce. Pathogens also increase the production cost due to reduced yield and expenditure on PESTICIDES.

The correct option is (B) False

The explanation: SINGLE CELL Protein is rich in good quality protein but poor in fats because high protein and low-fat contents are desirable features of HUMAN food. Therefore, SCP can be used as food or feed.

The correct answer is (c) ACIDS

To elaborate: Microbial biomass can be raised using low-cost organic matter like that of sawdust, PADDY straw, paddy husk and industrial organic wastes and effluents like whey. However, care has to be taken to remove excess nucleic acids and heavy metals or toxins PRESENT in organic wastes.

The correct OPTION is (a) True

To explain I would SAY: The shift from grain to meat diets also creates more DEMAND for cereals as it TAKES 3-10 kg of grain to produce 1 kg of meat by animal farming. For example, a 250 kg cow produces only 200 grams of protein PER day while it eats 10-30 kg of food.

Correct option is (b) Single-celled yeast

Easiest EXPLANATION: The most COMMON SOURCE of single-cell protein is single-celled yeasts (e.g., Candida utilis) and filamentous fungus-like Fusarium graminearum. Single-cell protein is rich in GOOD quality protein.

Correct choice is (c) Spirulina

The best I can EXPLAIN: Microbes are being grown on an industrial scale as a source of good PROTEIN. Blue-green algae like Spirulina can be grown EASILY on MATERIALS like wastewater from potato processing PLANTS that contain starch.

The correct answer is (a) Methylophilus methylotrophus

To EXPLAIN I WOULD say: Certain bacterial species like Methylophilus methylotrophus have a HIGH rate of biomass production and GROWTH and are known to PRODUCE 25 tonnes of protein.

Right option is (d) Lava

Best explanation: Spirulina can be EASILY grown on MATERIALS like straw, molasses, animal manure and even sewage, to produce large quantities and can serve as food rich in protein, minerals, FATS and carbohydrates and vitamins. Incidentally, such utilisation also reduces ENVIRONMENTAL pollution.

The CORRECT ANSWER is (a) Single CELL Protein

The best explanation: SCP stands for Single Cell Protein. Single-cell protein is protein-rich cell BIOMASS of unicellular or multicellular ORGANISMS which is used as food or feed.

Correct option is (c) Embryo rescue

For explanation I would say: The APPLICATIONS of tissue CULTURE include Rapid clonal propagation, Somaclonal VARIATIONS, Transgenic plants, INDUCTION and selection of mutations, resistance to weedicides and tolerance to stress like pollutants, toxins, salts, drought, floods etc.

Right option is (d) Making virus-free PLANTS

Easiest explanation: Embryo culture is the technique of TAKING out young/fragile/dormant embryos from developing seeds and their GROWTH on a culture medium to form seedlings and then young plants. This technique is USEFUL in the multiplication of some RARE plants, e.g., Makapuno Nut.

Right CHOICE is (a) Hybrid PROTOPLASTS

The explanation is: Isolated protoplasts from two different VARIETIES of plants-each having a desirable character-can be fused to GET hybrid protoplasts, which can be further grown to form a new plant. These hybrids are called somatic hybrids while the process is called somatic hybridisation.

The correct answer is (a) True

To explain: Protoplast of tomato is fused with a protoplast of POTATO, and then is grown to FORM NEW hybrid plants which have combined properties of tomato and potato. This results in the formation of POMATO which is a somatic hybrid of tomato and potato.

The correct answer is (b) Plant CELL – cell wall

Explanation: Protoplast is a plant cell without a cell wall. Scientists have been able to ISOLATE single CELLS from plants and after digesting their cell WALLS have been able to isolate naked protoplasts (surrounded by plasma membranes).

The correct ANSWER is (B) Apple

The explanation: CULTURING of meristems is an important method of the recovery of HEALTHY plants from diseased plants. Hence, one can remove the meristem and grow it in VITRO to obtain virus-free plants. Scientists have succeeded in culturing meristems of banana, sugarcane and potato.

The CORRECT option is (c) Meristem

Explanation: When the plants are infected with a VIRUS, the meristem (apical and axillary) is free of the virus because the CELL division of meristem is FASTER than the rate of virus replication and MULTIPLICATION.

Correct option is (C) the medium must provide a carbon SOURCE

Explanation: Essential requirement of an artificial medium in which explant is being regenerated is that the medium must provide a carbon source such as sucrose and also inorganic salts, vitamins, amino acids and GROWTH regulators LIKE auxins, cytokinins, etc.

Correct choice is (d) Plants genetically identical to the ORIGINAL plant

Best explanation: Plants produced through tissue culture will be genetically identical to the original plant from which they were grown, i.e., they are SOMACLONES. Many important FOOD plants LIKE tomato, banana and APPLE, etc., have been produced on a commercial scale using this method.

The correct answer is (a) False

The best I can explain: The capacity to GENERATE a whole new plant from any cell is known as totipotency. The method of producing thousands of plants through TISSUE CULTURE is CALLED micropropagation.