PLANT BREEDING : A NUMBERS GAME

The average yield for cereals including wheat and barley is less than 2.2 tons per hectare on a world wide basis. Constraints to higher yields are due to various environmental stresses such as temperature, moisture, length of growing season, pollution, soil, weed, and disease and insect problems. Thus breeding plants for stress environments is the major function of the plant breeder. The question which must be asked is “Do we have enough genetic variability to make further progress?”. Or as suggested recently in many popular magazines, have yield plateaus been reached for most of our major food crops. In recent years, progress in cereal breeding has been slow, with breeding for grain yield per se becoming more difficult. It is now thought that 80 to 90 percent of the resources devoted to breeding goes just to maintain existing yield levels. Also as a breeder increases the number of traits desired in a new cultivar, the smaller the probability is that such progeny can be found. Thus, to increase this probability plant breeding programs make many crosses and grow large segregating populations. We must recognize that PLANT BREEDING is in fact A NUMBERS GAME.