Breeding of Vegetable, Spice and Tuber crops (2+1)

Mass Selection

• In mass selection, seeds are collected from (usually a few dozen to a few hundred) desirable appearing individuals in a population, and the next generation is sown from the stock of mixed seed.
• This procedure, sometimes referred to as phenotypic selection, is based on how each individual looks.
• Mass selection has been used widely to improve old “land” varieties, varieties that have been passed down from one generation of farmers to the next over long periods.
• An alternative approach that has no doubt been practised for thousands of years is simply to eliminate undesirable types by destroying them in the field. T
• he results are similar whether superior plants are saved or inferior plants are eliminated: seeds of the better plants become the planting stock for the next season.
• A modern refinement of mass selection is to harvest the best plants separately and to grow and compare their progenies.
• The poorer progenies are destroyed and the seeds of the remainder are harvested.
• It should be noted that selection is now based not solely on the appearance of the parent plants but also on the appearance and performance of their progeny.
• Progeny selection is usually more effective than phenotypic selection when dealing with quantitative characters of low heritability.
• It should be noted, however, that progeny testing requires an extra generation; hence gain per cycle of selection must be double that of simple phenotypic selection to achieve the same rate of gain per unit time.
• Mass selection, with or without progeny test, is perhaps the simplest and least expensive of plant-breeding procedures.
• It finds wide use in the breeding of certain forage species, which are not important enough economically to justify more detailed attention