NEET Practice Questions (MCQs) with Answers & Solutions

(b) Hybrid varieties were first developed in maize, which is a cross-pollinated crop. In such crops, the parents of hybrid varieties are ordinarily, inbred lines. An inbred line is a nearly homozygous line produced by continuous inbreeding in a cross-pollinated crop and is maintained by strict inbreeding. In maize, hybrid vigour or heterosis is exploited by the crossing of two inbred parental lines.

(c) New castle disease or Ranikhet disease is a very dangerous viral disease of poultry.

(a) A plant in which a gene has been transferred through genetic engineering is called a transgenic plant and the gene, so transferred is called a transgene. Golden rice is a promising transgenic crop which when released for cultivation will help in alleviation of vitamin A deficiency.

(d) Monoculture involves the exclusive cultivation of a single crop over wide areas. It is an efficient way to use certain kinds of soils but the crop plants grown in monoculture are highly prone to pests and thus, it carries the risk of an entire crop being destroyed with the appearance of a single pest species or disease.

(d) In meristem culture, the shoot apical meristem along with some surrounding tissue is grown in vitro. It is used for clonal propagation and recovery of virus-free plants. It is also potentially useful in germ plasma exchange and long-term storage of germ plasma through freeze preservation.Protoplast culture involves the culture of protoplasts (Plant cell without cell wall) on a suitable.                                                                 Embryo rescue is the culture of the incised immature embryo to raise plants.Anther culture involves the culture of anthers on artificial culture medium. It is helpful in obtaining haploid plants.

(b) In 1954, Dr. M. S. Swaminathan joined Indian Agricultural Research Institute (IARI) and started a research programme for developing nonlodging and fertilizer responsive varieties of wheat, on the lines of the work earlier initiated in rice. Dr. Swaminathan is the pioneer mutation breeder and called as "father of green revolution in India".

(b) Indian dwarf wheat (Triticum sphaerococcum) is endemic to southern Pakistan and northwestern India. It was one of the main winter crops grown by ancient Indian cultures.

(b) Spirulina is a blue-green algae. Spirulina platensis is one of the richest source of protein, containing 40-50 percent crude protein on dry weight basis which under favourable condition may reach upto 70 percent. Its protein has balanced composition containing all essential amino-acids and lysine and tryptophan being present in sufficient quantities. Spirulina is also rich in vitamines, particularly Vit. B₁₂, which is not common in plant products and contains considerable amounts of fats, carbohydrates and minerals. It's lipids are made up of unsaturated fatty acids that do not form cholesterol.

(c) Somaclonal variation refers to all types of variation occur in plants regenerated from cultured cells or tissues. Genetic changes take place in plant tissue culture and these changes take place in plant tissue culture and these changes are passed to their progenies. This technology can be used for disease resistance, improvement of quality and yield in plants.