Genetics And Plant Breeding - Study Mode
[#211] Brown heart disease is caused due to deficiency of
Correct Answer
(A) Boron
Explanation
Solution: Brown heart disease is caused due to deficiency of Boron. Boron regulates pentose phosphate pathway, and increases sugar translocation in plants. Due to deficiency of boron growth of roots stops and the disease 'brown heart'. Boron deficiency affects vegetative and reproductive growth of plants resulting in inhibition of cell expansion, death of meristem and reduced fertility. Plants contain B both in a water-soluble and insoluble form.
[#212] Match the following columns: Column I (Theory) Column II (Related Scientist) a. Theory of epigenesis 1. Charles Darwin b. Theory of pangenes 2. Wolf c. Theory of acquired character 3. August Weismann d. The germplasm theory 4. Lamarck
Correct Answer
(C) a-2, b-1, c-4, d-3
Explanation
Solution: a. Theory of epigenesis is proposed by Wolf. Epigenesis is, the thesis that every developing entity starts from unformed material, with form emerging gradually, over time, in the process of development. b. Theory of pangenes is given by Charles Darwin. In 1868 Charles Darwin proposed Pangenesis, a developmental theory of heredity. He suggested that all cells in an organism are capable of shedding minute particles he called gemmules, which are able to circulate throughout the body and finally congregate in the gonads. c. Theory of acquired character is given by Lamarck. Lamarck is best known for his Theory of Inheritance of Acquired Characteristics, first presented in 1801. If an organism changes during life in order to adapt to its environment, those changes are passed on to its offspring. d. The germplasm theory is proposed by August Weismann. August Weismann proposed the germ plasm theory in the 19 th century, before the foundation of modern genetics.
[#213] Reciprocal recurrent selection is used when a character is governed by
Correct Answer
(C) Both A and B
Explanation
Solution: Reciprocal recurrent selection is used when a character is governed by Additive genes and Non-additive genes. RRS is a cyclical breeding procedure designed to improve the cross of two populations from different heterotic groups by using both general and specific combining ability. This method is equally effective with incomplete, complete and overdominance. This method is used when a character is governed by both additive and non additive gene action.
[#214] Consider the following statements regarding synthetic varieties 1. Parental materials are always inbred lines. 2. Open pollinated materials are also used as parental lines. 3. There is no limit on the number of parental lines used. 4. Parental lines are always tested for their combining ability. Which of the statements given above is/are correct?
Correct Answer
(B) 2 and 4
Explanation
Solution: The following statements regarding synthetic varieties are correct: 2. Open pollinated materials are also used as parental lines. 4. Parental lines are always tested for their combining ability. A synthetic variety is developed by intercrossing several genotypes of known superior combining ability i.e., genotypes that are known to give superior hybrid performance when crossed in all combinations. Synthetic variety is a variety that is developed by inter-mating in all possible combinations some inbred lines with good general combining ability and mixing their seeds.
[#215] Emasculation of flower is necessary for hybridization in
Correct Answer
(B) Self pollinated plants
Explanation
Solution: Emasculation of flower is necessary for hybridization in Self-pollinated plants. Self pollination is condition in which pollen from the same plant or same flower fertilizes the ovule of the same flower. In such cases, for hybridization, emasculation is necessary. Emasculation is the removal of anther or stamen or the pollen of bisexual flowers.