Tag: method of plant breeding for crop improvement

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Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

Majority of improved Indian Rice varieties have arisen from a cross between

  1. Oryza sativa indica $\times$ Oryza nivara
  2. Oryza sativa indica $\times$ O. sativa japonica
  3. O. sativa japonica $\times$ O. nivara
  4. O. rufipogon $\times$ O. nivara.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Improved Indian rice varieties, such as those developed during the Green Revolution, were primarily derived from crosses between the indica subspecies (native to India) and the japonica subspecies (known for high yield).

Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

Aim of plant breeding is to

  1. Control pollution

  2. Keep soil fertile

  3. Produce improved varieties

  4. To maintain wild plants
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The primary objective of plant breeding is to create new and improved plant varieties that possess desirable traits such as higher yield, better nutritional quality, or disease resistance.

Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

Four inbred/pure lines of Maize are crossed. The cross is

  1. Double cross

  2. Dihybrid cross

  3. Tetrahybrid cross

  4. Tetraploid cross
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A cross involving four inbred or pure lines of maize is known as a double cross, which is commonly produced by crossing two different single-cross hybrids to restore vigor and uniformity in commercial maize production.

Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

A cybrid is hybrid carrying

  1. Genomes and cytoplams of two different plants

  2. Cytoplasms of two different plants

  3. Cytoplasms of two different plants but genome of one plant

  4. Genomes of two different plants

  5. Cytoplasms of several plants but genomes of two plants.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A cybrid (cytoplasmic hybrid) is produced by the fusion of a protoplast containing a nucleus and cytoplasm with a cytoplast (a cell without a nucleus). Thus, it contains the cytoplasm of both parents but the nuclear genome of only one.

Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

From which technique, new and better varieties of crop plants are formed

  1. Selection

  2. Hybridisation

  3. Grafting

  4. Hybridisation followed by selection.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Plant breeding typically involves hybridizing parents with desirable traits, followed by the selection of the best offspring from the resulting population to stabilize those traits.

Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

During hybridisation, offspring with hybrid vigour superior to both parents are self pollinated for a few successive generations to .............

  1. Retain their parental characters

  2. Remove their parental characters

  3. Get homozygosity

  4. Segregate characters.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Self-pollination of hybrid offspring over several generations leads to the segregation of alleles and an increase in homozygosity, which helps in stabilizing the desired traits.

Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

During somatic hybridisation in plants

  1. Somaclones are produced in large numbers

  2. Apical meristems are cultured to get virus-free plant

  3. Cell walls and middle lamella are digested before fusing the cells

  4. Crop plants with higher levels of vitamins, proteins, and minerals are hybridised.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Somatic hybridization involves the fusion of protoplasts. To achieve this, the cell walls must be removed using enzymes like cellulase and pectinase to allow the plasma membranes to fuse.

Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

For hybridisation, which part is removed from bisexual flowers

  1. Stigma

  2. Stigma and style

  3. Anthers

  4. Ovary.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Emasculation is the process of removing the anthers from a bisexual flower to prevent self-pollination, ensuring that the flower can only be fertilized by the desired pollen during hybridization.

Multiple choice botany plant breeding method of plant breeding for crop improvement plant breeding for food production biotechnology

Consider the following statements: Hybrid plants can show.
a. Sterility
b. Mosaicism
c. Crossing over
d. Vigour
e. Homozygosis
Which of the statements are correct?

  1. $2, 3$ and $5$
  2. $2, 4$ and $5$
  3. $1, 2$ and $4$
  4. $1, 3$ and $4$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Hybrid plants can exhibit sterility due to meiotic irregularities, mosaicism from somatic mutations or chromosomal variation, and hybrid vigor (heterosis). Crossing over is a normal meiotic process occurring in all sexually reproducing plants, not uniquely a hybrid feature, and hybrids are typically heterozygous rather than homozygotic.