Genetics And Plant Breeding - Study Mode

[#291] The term cybrid refers to the
Correct Answer

(A) Somatic hybrids

Explanation

Solution: The term cybrid refers to Somatic hybrids. A cytoplasmic hybrid or cybrid is a eukaryotic cell line produced by the fusion of a whole cell with a cytoplast. Cytoplasts are enucleated cells, that is without a nucleus or genetic material. A cybrid is then a hybrid cell that mixes the nuclear genes from one cell with the mitochondrial genes from another cell. It is valuable in mitochondrial research and has been used to provide suggestive evidence of mitochondrial involvement in Alzheimer's disease, Parkinson's disease and other conditions.

[#292] Performance of a double cross hybrid can be predicted by taking the average performance of
Correct Answer

(A) The inbreds involved in marking the double cross

Explanation

Solution: The performance of a double cross hybrid can be predicted by taking the average performance of the inbreds involved in marking the double cross. Double cross hybrids are the product of crossing two distinct single crosses. The name of Donald F. Jones is probably most commonly associated with the double-cross technique, the method that made hybrid corn practical. The performance of double-cross hybrids was predicted based on the performance of single and three-way crosses.

[#293] A polyploid having chromosome sets from different sources such as different species is known as
Correct Answer

(D) None of these

Explanation

Solution: A polyploid having chromosome sets from different sources such as different species is known as an allopolyploid, none of the given options. An Autopolyploid is an individual or strain whose chromosome complement consists of more than two complete copies of the genome of a single ancestral species. Aneuploid is an individual having an abnormal number of chromosomes in a haploid set. A tetraploid is an individual having or being a chromosome number four times the monoploid number of a tetraploid cell.

[#294] The sum total of all the seed attributes that can withstand emergence under favourable condition is called
Correct Answer

(B) Vigour

Explanation

Solution: The total of all the seed attributes that can withstand emergence under favourable conditions is called vigour. Seed vigour is the energy or stamina of the seed in producing elite seedlings. It is the total of all seed attributes that enables its regeneration under any given conditions. Seed vigour determines the level of performance of seed or seed lot during germination and seedling emergence.

[#295] The mineral consituent of cell wall is
Correct Answer

(C) Calcium

Explanation

Solution: The mineral constituent of the cell wall is calcium. A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It is composed of the polysaccharides cellulose, hemicelluloses and pectin. The cells are held together and share the gelatinous membrane called the middle lamella, which contains magnesium and calcium pectates.