UNIVERSITY OF AGRICULTURAL SCIENCES COLLEGE OF SERICULTURE CHINTAMANI SUBMITTED TO : MARAPPA SIR SUBMITTED BY:Dept of genetics lakshmi shree AL(c) 0027

3

Pedigree Method

INTRODUCTION

Essentially a plant to row system to develop near pure lines

Followed by performance testing of resulting strains

This method and its variants require a lot of record keeping

DefinationPedigree refers to record of the acestry of an

individual plant.Pedigree breeding is a method of genetic

improvement of self pollinated species in which superior genotypes are selected from segregating and proper record of ancestry of selected plants are maintained in each generation.

Selection during

inbreeding

Early generations:

High heritability

traitsLate

generations:low

heritabilitytraits

Pedigree

PROCEDURE Generation year No of plants

or progeny to be grown

No of plants or progeny to be selected

F1F2F3F4F5F6F7F8

F9

F10

12345678

9-13

14

75100001000200130502510

10

-

ALL1000200130502510Prelminary yield trail testing Multiplication trail & identification of superior strain The best strain is released as a variety

Genetic Considerations:1.Additive genetic variability decreases

within lines and increases among lines, assuming no selection.

2.Dominant genetic variability complicates pedigree selection homozygous and heterozygous individuals look alike and

therefore you may continually select the heterozygote.

THUS, selection can be discontinued with phenotypic uniformity within a line is obtained

Advantages

1. Eliminates unpromising material at early stages;

2. Multi-year records allow good overview of inheritance, and more effective selection through trials in different environments,

3. Multiple families (from different F2 individuals) are

maintained yielding different gene combinations with common phenotype

4. Allows for comparison to other breeding strategies

Disadvantages

1. Most labor, time and resource intensive method; usually compromise between crosses and population sizes;

2. Very dependent on skill of breeder in recognizing promising material.

3. Not very effective with low traits4. Slow; can usually put through only one generation

per year, and the right environmental conditions must be at hand for accurate selection.

5. Upper ceiling set by allelic contents of F2,can not purge selections of undesirable alleles once ‘fixed’.

Thank you….