Tag: method of plant breeding for crop improvement

• The crossing between genetically different plants to produce a new variety is called hybridization.
• Genetically modified crops can be produced by the insertion of genes with desired traits by the process of hybridization.
• The plants of potato and tomato are the plants of the different genus. These plants are allowed to perform hybridization.
• The resulting plant variety is known as pomato. Cherry-type tomatoes are grown on the climber while the potatoes are developed below the soil. 
  
  

Carnauba wax is made from the leaves of the palm tree. It is also known as palm wax. It is obtained from the leaves of the carnauba palm by collecting and drying them, beating them to loosen the wax, then refining and bleaching the wax.

Black rust (or stem rust) of wheat is a fungal disease caused by the pathogen Puccinia graminis tritici.

Late blight of potato is caused by Phytophthora infestans a oomycetae (fungi). Cool climate and wet weather help infection and spread, responsible for the irish famines in the nineties.

• Mutation breeding is the process of exposing seeds to certain chemicals and radiation in order to generate mutants with desirable traits to bred with other cultivators. This will change the base sequence of genes of crop plants. In mung bean, resistance to yellow mosaic virus and powdery mildew were induced by mutations.
  
• Recombinant DNA technology is the process of joining DNA molecules together from 2 different species that are inserted into a host organism to produce new genetic recombinations.
• Transgenic mechanism is the mechanism of random integration of foreign DNA in transgenic animals.
• Gene therapy is a therapeutic process of delivery of nucleic acid into a patient's cell as a drug to treat a disease.

Heterosis is also called as hybrid vigour. It is the increase in such characteristics as size, growth rate, fertility and yield of a hybrid organism over those of its parents. Plant and animal breeders exploit heterosis by mating two different pure-bred lines that have certain desirable traits. Because of this, hybrids are generally found to be superior to their parents. Thus, the correct answer is option B.

 A mutation is a permanent change in the sequence of DNA. Mutations can be caused by external (exogenous) or endogenous (native) factors, or they may be caused by errors in the cellular machinery. Physical or chemical agents that induce mutations in DNA are called mutagens and are said to be mutagenic. Exogenous factors: environmental factors such as sunlight, radiation, and smoking can cause mutations. Endogenous factors: errors during DNA replication can lead to genetic changes as can toxic by-products of cellular metabolism.

Gurdev S. Khush crossed 13 varieties of rice from Oryza nivara to develop IR - 36 which was resistant to grassy stunt virus.