Discuss the role of fishery in enhancement of food production.

Explanation

Plant breeding is the manipulation of plant species so as to create new improved varieties that are better suited for cultivation, give better yield and are resistant to damage from pests and pathogens. Conventional plant breeding started with the dawn of civilisation when humans began domesticating plants, some 9000-11000 years back. It mainly consisted of picking up useful variations or selection. Domestication is changing of wild species and raising them under human management. Most of plant domestications occured in pre-historic times, some 7000-1000 years back. Later on very few domestications took place. As the effect of sexual reproduction came to be known in developing variability and combining traits of different varieties, the science of plant breeding based on hybridisation came into existence. Later on importance of pure lines, old varieties and wild relatives also became known. Then germplasm collection centres were set up. Classical plant breedmg involves choosing of pure lines with desired characters, their hybridisation and selection of plants with the targeted combination of characters. Now molecular biology and tissue culture have also become part of plant breeding.
Plant breeding or development of new varieties is carried out to obtain (i) Higher yield (ii) Improved quality like good baking, more preserving quality (in fruits and vegetables), biofortification, removal of antinutritional and toxic factors, (iii) Resistance to pathogens and pests, (iv) Increased tolerance to adverse environmental conditions like salinity, drought, low or high temperature, (v) Shorter maturity duration, (vi) Better agronomic traits, (vii) Wider adaptability. However, development of new varieties is not an easy job. It takes several years of labour on the part of several workers. For example, twelve years were spent in developing Wheat variety HUW-468. Plant breeding for development of new varities is carried out in a systematic way by Govt. agencies, commercial companies and agricultural universities.