Plant Breeding: Meaning and Objectives

Plant breeding is the purposeful, scientifically guided improvement of crop plants -- applying genetic principles to develop plant types that yield more, resist disease and adverse conditions better, and better meet human needs, than the wild or traditionally cultivated plants they are derived from. Unlike the slow, largely unconscious selection early farmers practised over thousands of years simply by saving seed from the best-looking plants, modern plant breeding is a deliberate programme carried out by trained plant breeders working toward clearly defined goals.

Why breed a new variety at all?

No single existing variety of a crop is ideal for every purpose, every region and every season, so a plant breeding programme is always begun with one or more specific objectives in view. The commonest objectives are:

• Higher yield per unit area, so that more food is produced from the same land.
• Improved quality of the harvested produce -- for example, a higher protein content in wheat or pulses, a better oil profile in an oilseed, or better baking or cooking quality in grain.
• Resistance to biotic stresses -- the ability to withstand attack by fungal, bacterial and viral pathogens, insect pests and nematodes, without needing heavy use of pesticides.
• Resistance to abiotic stresses -- the ability to tolerate drought, waterlogging, salinity, heat and cold better than existing varieties.
• Change in maturity duration, so a crop can be harvested earlier (freeing the field for a second crop in the same season) or later, as local farming patterns require.
• Wider adaptability, so a single variety can be grown successfully across more than one agro-climatic region. …