Tag: biology

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Multiple choice biology improvement in food resources crop variety improvement improvement if crop varieties improvement in crop variety

The aim of plant breeding is to produce_____________

  1. Disease-free varieties

  2. High-yielding varieties

  3. Early-maturing varieties

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

  • Plant breeding aims to improve the characteristics of the plant so that they become more desirable agronomically and economically. 
  • Thus, the chief objective of plant breeding is to develop such improved varieties of crop plants that will be commercially successful. 

Therefore, the correct answer is option D.

Multiple choice biology improvement in food resources crop variety improvement improvement if crop varieties improvement in crop variety

The first artificial interspecific plant hybrid was produced by 

  1. Cotton Mather

  2. Joseph Koerauter

  3. Thomas Fairchild

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The crossing between genetically different plants to produce a new variety is called as hybridization. Genetically modified crops can be produced by insertion of genes with desired traits by the process of hybridization. The first artificial interspecific type of hybridization was produced by Thomas Fairchild. The organism is known as Fairchild mule. This development was performed in the year 1717. 
Thus, the correct answer is option C. 
Multiple choice biology improvement in food resources crop variety improvement improvement if crop varieties improvement in crop variety

.......... is responsible for hybridization.

  1. Haploidy

  2. Polyploidy

  3. Seggregation

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Presence of three or more sets of chromosomes in an organism is called polyploidy. It is often seen in plants and very rare in animals. It is caused due to the non disjunction of the sister chromatids during the recombination (at meiosis). It can be induced in plants and cell cultures with the help of some chemicals like colchicine. Polyploidy causes variation, as it adds new genomes into a species. It has been widely used in producing hybrids of wheat. Ploidy level also effects some characteristics of plants. For example, higher ploidy leads to the larger cell size. So, the correct answer is B.

Multiple choice biology improvement in food resources crop variety improvement improvement if crop varieties improvement in crop variety

In crop improvement programme, haploids are important because they

  1. Require one half of nutrients

  2. Are helpful in study of meiosis

  3. Grow better under adverse conditions

  4. Form perfect homozygous individuals on diploidisation.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In crop improvement programme, haploids are important because they form perfect homozygous lines. Homozygous are the pure line selection plants resulting from self pollination. In this way, considerable homozygosity is obtained. Haploids are those plants which possess a gametophytic number of chromosomes. Haploids are used in plant breeding, especially for the production of homozygous plants and in their studies in the detection of mutation.

So the correct answer is ' Form perfect homozygous individuals on diploidisation'

Multiple choice biology improvement in food resources crop variety improvement improvement if crop varieties improvement in crop variety

Genetic diversity in agricultural crops is threatened by -

  1. Introduction of high yielding varieties

  2. Intensive use of fertilizers

  3. Entensive intercropping

  4. Intensive use of biopesticides
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The widespread adoption of high-yielding, uniform varieties leads to the replacement of local landraces, thereby reducing genetic diversity.

Multiple choice biology reproduction and modification in plants importance of pollination flower: parts of a flower flower and pollination

Even in absence of pollinating agents seed setting is assured in 

  1. Commelina

  2. Zostera

  3. Salvia

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

Even in absence of pollinating agents, seed setting is assured in Commelina, which is also called as 'Asiatic dayflower'. They lack nectar, they offer only pollen as a reward to their visitors. To attract pollinators, the plant has three types of brightly coloured floral organs: the large blue petals, fertile yellow anthers and infertile yellow antherodes that lack pollen.