Crop improvement is defined as the science that deals with the development of new crop varieties with superior quality and quantity. In other words, crop improvement refers to the ways of developing and breeding of crop varieties which are better than the existing varieties in a number of characters.
As a result of the ever increasing world population, modern scientific methods of crop improvement became necessary in order to increase productivity as well as maintain quality of food crops. Man has identified certain crop plants that are useful to him, and learnt that if he could select viable seeds for planting and adopt good cultural practices, he could obtain large quantity and quality of food needed for human and industrial purposes. This is the main purpose of crop improvement.
Aims of Crop Improvement
The plant breeders involved in improving our crops usually have certain aims in mind when doing their work. They try to substitute the undesirable characters in plants with desirable ones so that higher yields will be produced with improved quality. The aims of crop improvement therefore include:-
- To increase yield: The varieties of crops so developed by breeders are capable of giving very high yield or quantity of crops per unit of land. This quantity is measured in kg/ha, e.g. high yield of tomato plant from 800kg/ha to 2000 kg/ha.
- To improve the quality of produce: The quality of farm produce enhances its usefulness and value. Plant breeders can improve on the taste, colour, size, nutritive value and fibre content of crops.
- To adapt to climatic conditions: Plant breeders develop varieties of crops that are able to withstand extreme conditions of cold, drought and wind by adjusting the growth cycle of the variety better to suit the available growing season.
- To increase resistance to diseases: Plant breeders also develop varieties of crops which are not only resistant to diseases but produce high yield in the presence of diseases.
- To increase resistance to pests: It is also the aim of plant breeders to develop varieties of crops which are not only resistant to diseases but produce high yield in the presence of pests.
- To meet the needs of growers: Improvements in farming methods may make particular characteristics desirable to growers in their plants. For example, many growers would prefer short variety of maize which can be harvested by machine, instead of tall ones which can only be harvested by hand.
- To produce crops with uniform agronomic characteristics: One of the aims of plant breeders is to breed crops which can grow and mature uniformly to facilitate mechanisation or ease of harvesting.
- To breed crops with early maturity: Plant breeders are involved in the production of crops which will mature early. This can allow for the production of that crop many times in a year, depending on the crop.
- To improve harvesting qualities: Breeders try to produce crops that can be harvested with ease and without damage to the seeds/fruits.
- To improve the nutritional value of the produce: It is the ultimate aim of plant breeders to develop crops that have nutritional value like high protein, mineral, vitamin, etc which are useful to man.
- To meet the needs of consumers (processors or industralists): The demand by food processors as well as other consumers creates pressure for new quality of plants. For instance, improved quality in farm products, e.g. maize with high protein content will contribute to good health of the people.