R Genes

Q.

A plant can be made disease-resistant by

1. Breeding

2. Hormones

3. Colchicine

4. Heat

Q. ___is the ability of host plant to prevent the pathogen from causing disease

Q. How would you produce virus free progeny from a virus infected plant? [2 marks]

Q. Plants are generally immune to a wide variety of pathogens. This is due to

1. The genetic constitution of the plant
2. Resistance genes present in the plant
3. Conducive environment for growth
4. Less moisture in the atmosphere

Q. Two of the steps involved in producing nematode resistant tobacco plants based on the process of RNAi are mentioned below. Write the missing steps in its proper sequence.
(a).........., (b)using Agrobacterium as vector introduce it into tobacco., (c) ......... , (d).......... (e)initiates-RNA interference, (f).......... (g)......... , (h) ..........

Q. Exposure of plants to high fluoride concentration results in necrosis or chlorosis characteristically in

1. Petiole but not in lamina
2. Only mid rib in lamina
3. Leaf tip and leaf margins
4. Stem tips only

Q. ___is the ability of host plant to prevent the pathogen from causing disease

Q. Triticale is developed by ____________ method.

1. Somatic hybridization
2. Genetic engineering
3. Sexual reproduction
4. Cross pollination

Q. Plants are generally immune to a wide variety of pathogens. This is due to

1. The genetic constitution of the plant
2. Resistance genes present in the plant
3. Conducive environment for growth
4. Less moisture in the atmosphere

Q. Dodder can transmit

1. Both A and B
2. Mycoplasmal diseases
3. Bacterial
4. Viral diseases

Q. Highest growth is found in

1. Static phase
2. Exponential phase
3. Descending phase
4. Lag phase

Q. The infective stage of Fasciola hepatica for primary host is

1. Redia
2. Metacercaria
3. Sporocyst
4. Miracidium

Q. Plants are generally immune to a wide variety of pathogens. This is due to

1. The genetic constitution of the plant
2. Resistance genes present in the plant
3. Conducive environment for growth
4. Less moisture in the atmosphere

Q. ___is the ability of host plant to prevent the pathogen from causing disease

Q. Maleic hydrazide is used by tobacco growers as a

1. Wound hormone
2. Growth stimulating hormone
3. Axillary buds retardation
4. Bactericidal substance