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

Maintenance of pedigree record

• The pedigree record may be kept in several different ways, but it should be simple and accurate. Generally, each cross is given a number; the first two digits of this number refer to the year in which the cross was made, and the remaining digits denote the serial number of the cross in that year. For example, the number 7911 denotes the cross number 11 of year 1979. In the segregating generations, one of the following two systems of designation may be followed.

Designation Based on the Location of Progeny Rows in the Field

• In the first system, individual plant progenies in each generation are assigned row numbers corresponding to their location in the plot. In addition, each progeny in F4 and the subsequent generations is assigned the row number of the progeny in the previous generation from which it was derived. Thus each F3 progeny, derived from individual F2 plants, is given a number corresponding to the row number at which it is located in the F3 plot. Plants selected from an F3 progeny are identified by the row number of that progeny. When individual plant progenies are grown in F4, each progeny is also given the row number of the F4 plot at which it is located in addition to the F3 row number.


• Similarly, the plants selected from a progeny in F4 are given the row number of that progeny in the F4 plot. After the F5 progenies are planted, the row numbers of progenies in the F5 plot are added to the F4 row numbers. The same procedure is followed in the subsequent generations. Thus each progeny can be traced back to the F3 progeny (or the F2 plant) from which it originated. But for determining the pedigree of a progeny, the breeder has to consult the records of the previous years as well.

Designation Based on Serial Numbers of Selected Plants

• In the second system, in each generation, the selected plants are assigned serial numbers within individual progenies; each progeny or selected plant bears the serial numbers of all the plants in the previous generations related to it by direct descent. Thus each selected plant F2 is given a serial number; the F3 progenies derived from these plants are given the serial numbers of their parent F2 plants. The plants selected from a progeny in F3 are given the number of that progeny; in addition, each selected plant from that progeny is also given a serial number.

The system of designating individual plant progenies based on progeny row numbers of the concerned and the previous generations

Generation	Progeny number	Description
F2	7911-43	Progeny 11 No. 43 (Individual plant of whole F2 population of cross 11 made in the year 1979
F3	7911-7	Progeny in the 7th row in the F3 plot.
F4	7911-7-4	Progeny in the 4th row in the F4 plot, selected from the progeny in the 7th row of the F3 plot.
F5	7911-4-14	Progeny in the 14th row in the F5 plot, selected from the progeny in the 4th row in the F4 plot.
F6	7911-14-3	Progeny in the 3rd row in the F6 plot, selected from the Progeny in the 14th row in the F5 plot.


• These two numbers together make up the progeny numbers in the F4 generation. Similarly, the plants selected from an F4 progeny are given the F4progeny number, i.e. the serial numbers of the F2 and the F3 plants from which the concerned F4 progeny was derived and a new number showing the serial number of the plant among those selected from the F4 progeny. In this system, the pedigree of a progeny is immediately known, and one does not have to refer to the previous year’s records. But there is a greater chance of error in this system since more numbers are to be recorded. The breeder may, however, devise his own system of record keeping.
The system of designating individual plant progenies based on the serial numbers assigned to the selected plants

Generation	Progeny number	Description
F3	7911-7	Progeny obtained from plant number 7 selected in F2
F4	7911-7-4	Progeny from plant number 4, selected from the F3 progeny derived from the plant number 7 selected in F2
F5	7911-7-4-2	Progeny form plant number 2, selected from the F4 progeny derived from plant number 4 selected from the F3 progeny obtained from the plant number 7 selected in F2
F6	7911-7-4-2-8	Progeny from plant number 8, selected from the F3 progeny derived from the plant number 2 selected form the F4 progeny of the plant number 4 selected from F3 progeny of the plant number 7 selected in F2.


• In both the systems, the progenies are assigned a different serial number when they become homozygous and are included in preliminary yield trials. This serial number is given only to those homozygous lines that are included in preliminary yield trials.


• In the pedigree record, a brief note is made about the distinguishing features of each progeny. In keeping a pedigree record, the following should be kept in mind.
1. Only important characteristics should be recorded. If a large number of characters are noted, the record keeping would become a great burden.
2. Only promising progenies should be included in the record. Post progenies may be simply marked ‘discard’. This would give more time for studying promising progenies.
3. The pedigree record must be accurate. Keeping no record is better than keeping an inaccurate record, which will only create confusion.


• The pedigree record is often useful in the elimination of some progenies. In late generations, e.g. F5, F6 etc., if some lines originated from the same F4 or F5 progeny and are similar, only one of these lines need be maintained. Further, it may often be possible to obtain a general idea about the inheritance of characters by studying the pedigree record