Crop production can be increased by adopting a number of methods like using seeds of improved varieties, using modern method of agriculture, using fertilizers and pesticides. An improved seed variety is most important for better yield.

Hybrid obtained from two different plants have one or more traits superior than either of parents. This condition of having superiority of the hybrid is called heterosis.

The correct option is Option D.
Biopesticides are derived from animals, plants and other natural materials such as fungi, bacteria, algae, viruses, nematodes and protozoa.

plants with superior phenotype is selected form the different varieties of particular species for further propagation. This process is called mass selection. It is a method of improvement in plant varieties.

Polyploidy is a condition in which multiple sets of chromosome is present in same cell in place of usual two sets (diploid). Cell division involves karyokinesis followed by cytokinesis. Colchicine prevents the cytokinesis that results the more than two sets of chromosome.

The theory of inheritance of acquired traits is given by Weismann. Mendel gave the theories of inheritance that includes the law of dominance, the law of segregation and the law of independent assortment.

In meristem culture, the shoot apical meristem alongwith  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.

Emasculation is the technique of removing anther from bisexual flower to prevent self-pollination. The stigma is further covered with butter paper to prevent air born pollination.

Himgiri wheat variety is resistant to disease like leaf and strip rust and hill bunt disease that cause great loss of productivity due to loss of plant parts.

Pure line is necessary for carrying out breeding programmers. Pure line is obtained by inbreeding plants followed by test crossing until we get homozygous plants for particular traits.