Genetics And Plant Breeding - Study Mode

[#686] Land races are
Correct Answer

(B) Local varieties

Explanation

Solution: Landraces are Local varieties. Landraces are defined as dynamic populations of a cultivated plant with a historical origin, and distinct identity, often genetically diverse and locally adapted and associated with a set of farmer's practices of seed selection and field management as well as with a farmer's knowledge base.

[#687] In maize cob sorting is done to identify
Correct Answer

(C) Off-type cobs

Explanation

Solution: In maize, cob sorting is done to identify off-type cobs. Off-type means any seed or plant not a part of the variety in that it deviates in one or more characteristics from the variety as described. The cobs which show the difference in seed rows, seed number, and colour should be identified and removed. And the cobs with very less seeds also should be removed.

[#688] Tonoplast is
Correct Answer

(D) Outer membrane of vacuole

Explanation

Solution: Tonoplast is outer membrane of vacuole. The vacuole is a membrane-bound organelle that is present in plant and fungal cells and some protist, animal and bacterial cells. A vacuole is surrounded by a membrane called the tonoplast and filled with cell sap. In 1885, de Vries named the vacuole membrane as tonoplast. It is the cytoplasmic membrane surrounding a vacuole, separating the vacuolar contents from the cell's cytoplasm.

[#689] If 'n' is no. of Inbred line then total no. of double cross is
Correct Answer

(C) $$frac{{{ ext{n}}left( {{ ext{n}} - 1} ight)left( {{ ext{n}} - 2} ight)left( {{ ext{n}} - 3} ight)}}{8}$$

Explanation

Solution: If 'n' is no. of the Inbred line then total no. of the double cross is $$frac{{{ ext{n}}left( {{ ext{n}} - 1}
ight)left( {{ ext{n}} - 2}
ight)left( {{ ext{n}} - 3}
ight)}}{8}$$ The double cross was the basic technique used in developing modern hybrids and has been used by commercial firms since. Jones's invention was to use four inbred lines instead of two in crossing. In the poly cross, selected inbreds are allowed to intermate by open pollination with a random sample of pollen from a number of selected lines.

[#690] Okazaki fragments are formed due to synthesis of DNA in direction
Correct Answer

(A) 5' - 3'

Explanation

Solution: Okazaki fragments are formed due to synthesis of DNA in directions 5' - 3'. Okazaki fragments are short sequences of DNA nucleotides that are synthesized discontinuously and later linked together by the enzyme DNA ligase to create the lagging strand during DNA replication. It was discovered in the 1960s by the Japanese molecular biologists Reiji and Tsuneko Okazaki. These enzymes can only work in the 5’ to 3’ direction, the two unwound template strands are replicated in different ways.