The need for crop improvement
Food is the basic necessity of life; without it mankind cannot survive. The amount of food needed to feed the human beings on this planet is given by the following equation.
Total food needs of the world =
number of persons to be fed x food needed by one person
The food needs of the world and different countries increase with increase in population. The only way to produce food in this world of finite resources is through the process of photosynthesis, which is actually harvesting sunlight. Only plants can photosynthesize, and they are capable of capturing solar energy in the form of chemical bonds in compounds which are constitutes of the food we eat. Agronomists are responsible for fulfilling the food need of human beings by growing plants that produce food or other useful products like fiber, forage, drugs, and condiments, i.e. crops.
Total food production depends upon the total area under food crops and food produced per unit area.
Total food produced = area sown x yield per unit area
The greater food supply required to feed the increasing population must come from increased yield per unit area. Higher yields per unit area and better quality can be obtained by crop improvement. Agronomists have the
challenging job of feeding human beings and feeding them well; to achieve this objective they must improve production of crops by planting improved varieties and using improved production technology. Knowledge of the
principles and practices of crop improvement is, therefore, essential for enhancing crop productivity per unit area.
A crop is a community of plants grown under field conditions for its economic value. Crop improvement means improving the ability of these plants to produce the useful parts for which they are grown. Plant growth is
a result of the interaction between the genetic makeup of the plant and the environment under which that crop is grown. That is, it results from translation of the genetic code in the seeds under conditions conducive to germination, seedling emergence, growth, and development.
To improve crops, we can manipulate the basic genetic codes. Crop improvement can also be effected by manipulation of the environment through advanced. Agro-technology so that the environment in the field is favorable for growth, development, and partitioning of assimilates into the economical1y useful plant parts. Crop improvement therefore involves both changing the genetic information in the plants to produce superior varieties (cultivars), and development of improved production technology. Both approaches are needed for increased crop production. Development of improved varieties is a stable method of crop improvement. Technological improvements must be applied each season to get improved production of crops. The maintenance, multiplication, and distribution of superior cultivars and extension of improved production technology fall within the field of crop improvement because they are needed to bring benefits of improved varieties from the laboratory
to the farmers’ fields.
Comprehensive crop improvement programs
Development of a comprehensive scientific crop improvement program requires knowledge of constraints to crop production. Knowledge of several disciplines is needed-plant physiology, genetics and cytogenetics, botany,
plant pathology, entomology, plant biochemistry, statistics, production, and computer science. Reliance on finding superior types by chance as was the case in the past is no longer sufficient.
A crop improvement program involves all or some of the following.
- Collection of naturally occurring germ plasm
- Screening and classification of germ plasm
- Maintenance and conservation of germ plasm
- Introduction and exchange of material
- Selection to identify superior material
- Hybridization to generate new genotypic combinations
- Creation of variation by mutagens
- Producing new species or cultivars by polyploidy and chromosome substitution
- Testing of single plants, lines, and populations
- Yield tests to find out the highest yielding varieties
- Approval and release of cultivars or germ plasm
- Maintenance of cultivars and their germ plasm
- Seed production
- Seed distribution
- Generation of production technology
Crop Production By Mr. Shafi Nazir, Managing Author,
Edited By: Elena Bashir, Robyn Bantel