Class 12th Biology 2017 Set1 Delhi Board Paper Solution
Question 8
In an agricultural field, there is a prevalence of the following organisms and crop diseases which are affecting the crop yield badly:
(a) White rust (b) Leaf and stripe rust (c) Black rot (d) Jussids
Recommend the varieties of crops the farmers should grow to get rid of the existing problem and thus, improve the crop yield.
Answer
Normal varieties of crops are prone to infection by various pathogens which lead to poor growth of crops. To get rid of existing problems, the farmers should grow improved hybrid varieties as these are mostly resistant to most pathogens and give higher yield.
| White rust | Pusa Swarnim (karan rai) | Brassica |
| leaf and stripe rust | Himgiri | Wheat |
| Black rot | Pusa Swarnim, Pusa snowball K-1 | Cauliflower |
| Jassids | Pusa Sem-2 | Flat Bean |
Popular Questions of Class 12th biology
- Q:- What is spermatogenesis? Briefly describe the process of spermatogenesis.
- Q:- Why is reproduction essential for organisms? Answer
- Q:- Write a short note on
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals. - Q:- With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.
- Q:- What is DNA fingerprinting? Mention its application.
- Q:- Describe the structure of a seminiferous tubule.
- Q:- What is oogenesis? Give a brief account of oogenesis.
- Q:- What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.
- Q:- With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.
- Q:- Explain the Law of Dominance using a monohybrid cross.
Recently Viewed Questions of Class 12th biology
- Q:- Which part of the plant is best suited for making virus-free plants and why?
- Q:- What are chasmogamous flowers? Can cross-pollination occur in cleistogamous flowers? Give reasons for your answer.
- Q:- Briefly mention the contribution of T.H. Morgan in genetics.
- Q:- What is vegetative propagation? Give two suitable examples.
- Q:- Using a Punnett square, work out the distribution of phenotypic features in the first filial generation after a cross between a homozygous female and a heterozygous male for a single locus.
- Q:- Differentiate between the following −
(a) Dominance and Recessive
(b) Homozygous and Heterozygous
(c) Monohybrid and Dihybrid. - Q:- Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (use the internet).
- Q:- In our society the women are often blamed for giving birth to daughters.
Can you explain why this is not correct? - Q:- Give three hypotheses for explaining why tropics show greatest levels of species richness.
- Q:- If the sequence of one strand of DNA is written as follows:
5-ATGCATGCATGCATGCATGCATGCATGC-3
Write down the sequence of complementary strand in 5→3 direction