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

Single Seed Descent (SSD)

• This method is modification of bulk method.
• First proposed by Goulden (1939) and later modified by Brim (1966).
• Instead of bulking whole seed lot of selected plants, a single seed is selected randomly from each selected plant to make bulk.
• This method involves less record keeping (pedigree method) and works better where the main focus is on improvement of quantitative traits or characters such as yield and earliness, rather than qualitative traits or characters such as flesh colour and disease resistance.

Important features

• The important features of this scheme are,

1. No special efforts for artificial selections or even there is no possibility for natural selection, till F5 or F6 when the population is reasonably homozygous, and
2. Raising of F 3 and later generations from a bulk of one seed from each F2 and subsequent generation plant in order to ensure that each F2 plant is represented equally in the end population. As a result of the speed and economy, the single seed-descent scheme is becoming increasingly popular with the breeder