Genetics And Plant Breeding - Study Mode
[#151] Triticale is offspring of
Correct Answer
(C) Wheat and rye
Explanation
Solution: Triticale is the offspring of Wheat and rye. Triticale is a hybrid of wheat ( Triticum ) and rye ( Secale ) first bred in laboratories during the late 19 th century in Scotland and Germany. When crossing wheat and rye, wheat is used as the female parent and rye as the male parent (pollen donor). The resulting hybrid is sterile and must be treated with colchicine to induce polyploidy and thus the ability to reproduce itself.
[#152] Chlorosis in sulphur deficient plants appears
Correct Answer
(C) First in the young leaves and then in the mature leaves
Explanation
Solution: Chlorosis in sulphur deficient plants appears first in the young leaves and then in the mature leaves. Sulphur is an immobile nutrient in the plant and thus the deficiency symptoms develop in the young leaves first, generally in or near the top of the plant, then it is passed on to mature leaves. Chlorosis starts from leaf margins and spreads inwards. Under severe deficiency, the entire plant may turn yellow leading to premature leaf fall, and reduced flowering and fruiting.
[#153] The variance which is fixable
Correct Answer
(A) Additive
Explanation
Solution: The variance is a fixable Additive. Additive genetic variance refers to the deviation from the mean phenotype due to the inheritance of a particular allele and this allele's relative (to the mean phenotype of the population) effect on phenotype.
[#154] The light receptor pigment present in seeds is
Correct Answer
(D) Phytochrome
Explanation
Solution: The light receptor pigment present in seeds is Phytochrome. Phytochromes are a class of photoreceptors in plants, bacteria and fungi used to detect light. They are sensitive to light in the red and far-red regions of the visible spectrum. They regulate the germination of seeds (photoblasty), the synthesis of chlorophyll, the elongation of seedlings, the size, shape and number, the movement of leaves and the timing of flowering in adult plants.
[#155] Number of barr bodies is
Correct Answer
(D) All of the above
Explanation
Solution: Several Barr bodies are one in female human beings, two in a female with Klinefelter syndrome, and one in male with Klinefelter syndrome. A Barr body or X-chromatin is an inactive X chromosome in a cell with more than one X chromosome, rendered inactive in a process called lyonization, in species with XY sex determination (including humans). In humans with more than one X chromosome, the number of Barr bodies visible at interphase is always one fewer than the total number of X chromosomes. In humans with euploidy, a genotypical female (46, XX karyotype) has one Barr body per somatic cell nucleus, while a genotypical male (46, XY) has none.