(OBJECTIVES OF PLANT BREEDING, Definitions, art part and Science Part of Plant Breeding, International Agricultural Res. Centres under CGIAR )
Definitions’ of Plant Breeding
Table of Contents
Plant Breeding is defined as changing the biological makeup of plants and crops to increase their yield and usefulness using various plant breeding methods.
“Plant Breeding is the art and science of changing the traits of plants in order to produce desired characteristics.” – (Sleeper and Poehlman, 1995).
“Plant Breeding is the genetic improvement of plants for human benefit.”
Plant breeding is a science based on principles of genetics and cytogenetics. It aims at improving the genetic makeup of the crop plants
The art part of Plant Breeding
The ability of the breeder to make a distinction between desirable and undesirable character Viz. shattering Vs. Non-shattering Pods or spike, More tillering vs. low tillering,. The selection skill does not have any underlying scientific facts.
Science Part of Plant Breeding
With the advent of inheritance laws, and the genetic role it become easy to transfer desirable traits through crossing methodology, or through the Biotechnological approach, Mutation, Polyploidy.
Plant Breeding aims to improve the various characteristics of plants so that they become more desirable agronomical and economically. Thus the chief objective of plant breeding is to develop such improved varieties of the crop plants that will be commercially successful.
Generally, a successful variety is one with a total balance of traits that makes it more profitable for the growers than any other one they might choose
Therefore, specific objectives would vary greatly depending on the crop and region. Some of the main objectives of plant breeding may be summarised here.
Objectives of Plant Breeding:
- Higher Yields
- Improved Quality
- Disease and insect resistance
- Change in maturity duration
- Agronomic characteristics
- Photo and thermosensitivity
- Synchronous Maturity
- Determinate Growth
- Moisture Stress and Salt Tolerances
- Elimination of Toxic substances
High Yields :
Most of the breeding programmes aim at higher crop yields. In fact, higher yields will always remain one of the main objectives of the breeding programme. This is achieved by developing more efficient genotypes, e.g., Hybrid varieties.
Improved Quality :
The quality of the plant produce determines its suitability for various uses therefore quality is an important aspect for plant breeders. E.g., milling and baking quality in wheat(Triticum aestivum) and cooking quality in Rice (Oryza sativa)
Disease and Insect Resistance :
Resistant varieties offer the cheapest, the most convenient, and environmentally safe method of disease and insect management. In some cases, they offer the only feasible.
means of control e.g. rusts in wheat. Resistant varieties not only increase production but also stabilise it.
Change in Maturity Duration :
Breeding for early maturing crop varieties or varieties suitable for different dates of planting may be important
objectives in many crops. This would permit new crops rotations and often extend the crop area. For example, the development of wheat varieties suitable for late planting has permitted rice-wheat rotation.
Modification of agronomic characteristics, such as plant height, tillering, branching, erect or trailing habit, etc.., is often desirable. For Example, dwarfness in Cereals is generally associated with lodging resistance and fertilizer responsiveness.
6. Photo- and Thermo Sensitivity:
Development of photo insensitive and Thermo insensitive wheat, and photo insensitive rice varieties has permitted their cultivation in new areas. Rice is now cultivated in Punjab while wheat is a major Rabi crop in West Bengal. In the case of wheat, photoperiod insensitivity is due to genes ppd1 and ppd2 which show polymeric gene action.
Synchronous Maturity :
Synchronous maturity is highly desirable crops like Mung (Vigna radiata), where several pickings are necessary
8. Non-shattering Characteristics :
This feature would be of great value in a crop like a mung where shattering is a major problem in the case of many commercial varieties
Determinate Growth :
Development of varieties with determinate growth habits is desirable in crops like mung, pigeon pea(Cajanus cajan), cotton(Gossypium Spp.).
In some crops, seeds germinate even before harvesting if there are rains at the time of maturity e.g., mung, barley etc. A period of dormancy in such crops would check the losses due to preharvest rains. But in some crops, it may be desirable to remove dormancy.
Moisture Stress and Salt Tolerance :
Development of varieties for rained areas and for saline soils would be helpful in increasing crop production in India.
The major proportion of calcium is up to 70% of cropped area and there are 7 to 20 million hectares are salt-affected (Saline) Soils.
Elimination of toxins :
Some crops have toxic substances, which must be eliminated to make them safe for For consumption.
For example, Khesari (Lathyrus sativus) seeds have a neurotoxins, β-N-oxalyl-α,β-diaminopropionic acid(BOAA) which causes paralysis of lower limbs. Similarly, brassica oil has erucic acid, which is harmful to human health. Removal of such toxic substances would increase the nutritional value of these crops.
Traditionally maize is a Kharif crop. But scientists are now able to grow maize as Rabi and Zaid crops.
International Agricultural Res. Centres under CGIAR
CIAT – International Center for Tropical Agriculture, Columbia
CIFOR – Center for International Forestry Research, Indonesia
CIMMYT – International Maize and Wheat Improvement Center, Mexico
CIP – International Center for Potato, Peru
ICARDA – International Center for Agricultural Research in the Dry Areas, Lebanon
ICRISAT – International Crops Research Institute for the Semi-Arid Tropics, India
IFPRI – International Food Policy Research Institute, Wash, DC
IITA – International Institute of Tropical Agriculture, Nigeria
ILRI – International Livestock Research Institute, Kenya
IPGRI – International Plant Genetic Resources Institute, Italy
IRRI – International Rice Research Institute, Philippines
IWMI – International Water Management Institute, Srilanka
WARDA – West Africa Rice Development Association, Liberia
World Agroforestry Centre (ICRAF), Kenya
World Fish Center, Malaysia