Pure Line

Q. What would be the phenotype of a plant that had a genotype Tt?

Q.

What Is Mass Selection?

Q. In plant breeding programme, haploid plants are important because:

1. They are disease resistant
2. They are more vigorous
3. They require less nutrients
4. They are used to obtain homozygous line

Q. In a plant population gene S shows four alternate forms- S1, S2, S3, S4, then how many types of genotype and phenotype will be represented respectively

Q. In a dihybrid cross where two parents (pea plants) differ in two pairs of contrasting traits, that is, pod color and pod shapes color, are crossed. Assuming that the male and female parent were homozygous dominant and recessive for both of these characters respectively, the number of green coloured pod among sixteen progenies of F2 generation will be

1. 12
2. 4
3. 6
4. 8

Q.

Define selection.

Q. Pure line can be created by

1. Self pollination
2. Cross pollination
3. Cross hybridisation
4. Selfing

Q. Which among the following is incorrect related to producing a new variety through plant breeding?

1. Pure lines with desirable characters are usually selected as parents
2. Usually only one in few hundred to a thousand crosses shows the desirable combination
3. The progeny obtained through hybridisation can be superior to both the parents
4. The hybrids produced are self-pollinated for several generations till they reach heterozygous state

Q.

Briefly explain the steps involved in plant breeding.

Q. Explain mass selection and pure line selection. How is pure line selection a better method for crop improvement?

Q. Differentiate between mass selection and pure line selection.

Q. Two pea plants one with yellow round seeds (YYRR) and another with green wrinkled seeds (yyrr) produce $F_1$ progeny that have yellow round seeds (Yy Rr). The possible new combination in $F_2$ generation is
A.Yellow Round
B. Yellow wrinkled
C. Green Round
D.Green wrinkled

1. B and C
2. A and B
3. C and D
4. A and D

Q. Mendel selected Pisum sativum for hybridisation experiments because of:

1. Clear contrasting characters and short life span
2. Long life span and non-fertile hybrids
3. Presence of unisexual flowers
4. Infertile hybrids and production of large number of seeds by each plant

Q. All plants of a pure line have

1. Same genotype
2. Similar phenotype
3. Same phenotype and different genotype
4. Same genotype and drastically different phenotypes

Q. What are micro-mutations?

1. Union of chromosomes
2. Reduction of chromosomes
3. Changes in genes
4. Polyploidy

Q. List various methods used for crop improvement. Describe how the objective is achieved by using any one of them.

Q. why vegetative propagation is an important part of horticulture? and why it eliminates the need of pollination?

Q. During artificial selection, which features of wild cabbage were selected to give rise to I] cabbage II] cauliflower

Q. Write a note on selection and testing of superior recombinants in plant breeding.

Q. Fill up the blanks in the following paragraph by selecting the correct option.
Inbreeding increases (i). Thus inbreeding is necessary if we want to evolve a (ii) in any animal. Inbreeding exposes harmful (iii) genes that are eliminated by selection.

1. (i) heterozygosity, (ii) pure line, (iii) dominant
2. (i) heterozygosity, (ii) breed, (iii) recessive
3. (i) homozygosity, (ii) pure line, (iii) recessive
4. (i) homozygosity, (ii) breed, (iii) dominant

Q. What are 'true breeding lines' that are used to study inheritance pattern of traits in plants?

Q. Most cultivated plants of world today are examples of

1. Mutation
2. Polyploidy
3. Hybridisation
4. Selection

Q. Select the incorrect option based on the characters selected by Mendel and his observations in pea plant.

1. Tt: genotype
2. Plants bearing axial flowers: phenotype
3. Plants having round seeds: dominant phenotype
4. Plants producing violet flowers: recessive phenotype

Q. Protoplasts of two different species are fused in

1. Micropropagation
2. Somatic hybridization
3. Clonal propagation
4. Organography

Q. Following is the diagrammatic representation of the operation of natural selection on different traits. Which of the following options correctly identifies all the three graphs A, B and C.

1. (A) Directional (B) Stabilizing (C) Disruptive
2. (A) Stabilizing (B) Directional (C) Disruptive
3. (A) Disruptive (B) Stabilizing (C) Directional
4. (A) Directional (B) Disruptive (C) Stabilizing

Q. In those plants whose pulp is of economical importance, they are generally propagated by vegetative means because

1. It is cheaper
2. The pulp quality remains same
3. The pulp quality becomes better
4. It is more economical

Q. Normal maize has starchy seeds which remain smooth when dry. A mutant form has sugary seeds which go wrinkled when dry. When a mutant was crossed with a normal plant, a F${}_1$ was produced which had smooth seeds. What would be the relative ratios of the different seed types, if the F${}_1$was allowed to self?

1. 1 smooth : 3 wrinkled
2. 3 smooth : 1 wrinkled
3. 1 smooth : 1 wrinkled
4. All wrinkled

Q. All plants of a pure line have

1. Same genotype
2. Similar phenotype
3. Same phenotype and different genotype
4. Same genotype and drastically different phenotypes

Q. Which among the following is incorrect related to producing a new variety through plant breeding?

1. Pure lines with desirable characters are usually selected as parents
2. Usually only one in few hundred to a thousand crosses shows the desirable combination
3. The progeny obtained through hybridisation can be superior to both the parents
4. The hybrids produced are self-pollinated for several generations till they reach heterozygous state

Q. Albinism in corn is due to

1. Pathogenic effect
2. Deficiency of light
3. Deficiency of minerals
4. Lethal gene effect