Genetics And Plant Breeding - Study Mode

[#356] Male sterility was reported by
Correct Answer

(B) Koelreuter

Explanation

Solution: Male sterility was reported by Koelreuter. Joseph Gottlieb Kolreuter was the first to document male sterility in plants. In the 18th century, he reported on anther abortion within species and specific hybrids. This could be because the male sporophyte and gametophyte are less protected from the environment than the ovule and embryo sac. Male-sterile plants can set seeds and propagate.

[#357] Guard cells in monocot leaves are
Correct Answer

(D) Dumb-bell shaped

Explanation

Solution: Guard cells in monocot leaves are Dumb-bell shaped. Monocots contain dumbbell-shaped guard cells, surrounding their stomata. Monocots contain stomata in both upper and the lower epidermis of leaves. Guard cells optimize leaf gas exchange in response to changing environmental conditions and their turgor is controlled by alterations in atmospheric CO 2 concentration, light intensity, humidity and the drought hormone abscisic acid.

[#358] In wheat and rice the genetic purity of a variety can deteriorates due to
Correct Answer

(C) Mechanical contamination with seeds of other varieties

Explanation

Solution: In wheat and rice, the genetic purity of a variety can deteriorate due to Mechanical contamination with seeds of other varieties. The genetic purity during multiplication stages is prone to contamination due to the presence of pollen shedders as well as physical admixtures during processing. The deterioration sets in due to natural crossing with undesirable types, diseased plants or off types.

[#359] Disease and insect resistance is governed by
Correct Answer

(D) All of these

Explanation

Solution: Disease and insect resistance are governed by Plasma genes, Oligogenes and Polygenes. The plasma gene is an extranuclear determiner of hereditary characteristics with a capacity for replication similar to that of a nuclear gene. Oligogene is a gene that produces or significantly affects the expression of a qualitative heritable characteristic, acting either alone or with a few other genes. A polygene refers to a group of genes that when expressed together produce a particular phenotype or trait.

[#360] The occurrence of genetic impurity is more in
Correct Answer

(A) Cross pollinated crop

Explanation

Solution: The occurrence of genetic impurity is more in Cross pollinated crops. Genetic impurity is defined as impurities that have been demonstrated to cause deleterious changes in the genetic material regardless of the mechanism. As cross-pollinated crop involves the transfer of pollen grains from the anther of one plant to the stigma of another plant, and it leads to a lot of genetic diversity as well as a genetic impurity.