7. gpb 621 estimation of heterosis & inbreeding depression

this is a PowerPoint presentation on principles of quantitative genetics for college students compiled in easy way to study

1. ESTIMATION OF HETEROSIS & INBREEDING
DEPRESSION
GPB 621 –PRINCIPLES OF QUANTITATIVE GENETICS
CLASS –7
Dr. K. SARAVANAN
Professor
Department of Genetics and Plant Breeding
Faculty of Agriculture
AnnamalaiUniversity

2. Dr.K. Saravanan, GPB, AU
•Shull in 1914
•Superiority of F1 hybrid over its parents.
•Inotherwords,heterosisreferstoincreaseofF1infitnessandvigour
overtheparentalvalues
•Heterosisreferstothephenomenon(cause),hybridvigouristhe
phenotypicexpression(effect)ofthegeneticalphenomenon.Incurrent
usage,heterosisandhybridvigourareusedassynonymsand
interchangeable
Heterosis

3. Dr.K. Saravanan, GPB, AU
Estimation of heterosis
The heterosiscan be classified into three on the basis of
estimation.
1. Relative heterosisover mid-parent -di
2. Heterobeltiosisover better parent -dii
3. Standard heterosis/ Economic heterosisover commercial hybrid /
variety -diii

4. Dr.K. Saravanan, GPB, AU
P
1 P
2 F
1
SPMP BP
Relative Heterosis(di)
Heterobeltiosis(dii)
Standard
Heterosis(diii)
HETEROSIS
P1 –Parent 1 Mean Value
P2 –Parent 2 Mean Value
F1 –P1 x P2
MP –Mid Parent value
BP –Better Parent Value
SP –Standard Parent Mean value

5. Dr.K. Saravanan, GPB, AU
Relative heterosis:
•ThesuperiorityofF
1hybridoverthemid-parentalvalue(i.e,mean
valueoraverageoftwoparentsinvolvedinthecross)isknownas
mid-parentheterosis,whichisestimatedasfollows:
Relative heterosispercent (di) = X 100
where,
F
1is the mean value of F
1hybrid
MP is the average of two parents involved in the cross
Significance of Relative heterosis:
t (di) = SE
d= MP
MPF
1 dSE
MPF
1 r
EMS
2
3

6. Dr.K. Saravanan, GPB, AU
Heterobeltiosis:
The superiority of F
1hybrid over the better parent or superior parent
Heterobeltiosis(dii)= x 100
Where,
F
1is the mean value of F
1hybrid
BPis the mean value of better parent/ Best parent of the particular
cross
Significance of Heterobeltiosis:
t (dii) = SE
d= BP
BPF
1 dSE
BPF
1 r
EMS2

7. Dr.K. Saravanan, GPB, AU
Standard heterosis:
•The superiority of F1 hybrid over the standard commercial variety / hybrid is known as
standard heterosis.
•The term useful heterosiswas used by Meredith and Bridge (1972). It is also called as
economic heterosis. This type of heterosisis of direct practical value in plant breeding
Standard heterosis(diii)= x 100
Where,
F
1is the mean value of F
1hybrid
SVis the standard variety / hybrid
Significance of Heterobeltiosis:
t (diii) = SE
d= SV
SVF
1 dSE
SVF
1 r
EMS2

8. Dr.K. Saravanan, GPB, AU
INBREEDING DEPRESSION:
•Todecreaseinfitnessandvigourduetoinbreeding.
•Thedegreeofinbreedingismeasuredbytheinbreedingco-efficient.
•Inbreedingdepressionresultsduetofixationofunfavorablerecessive
genesinF
2.
•Thefixationofallfavorabledominantgenesinonehomozygouslineis
impossibleduetolinkagebetweensomeunfavorablerecessiveand
favorabledominantgenes.

9. Dr.K. Saravanan, GPB, AU
ESTIMATION OF INBREEDING DEPRESSION:
•The inbreeding depression is estimated when both F1 and F2 populations of the same
cross are available.
Inbreeding Depression = x 100
Where,
F
1is the mean value of F
1hybrid F
2is the mean value of F
2generation
Significance of Inbreeding Depression :
t = SE
d=
Where SE
1, SE
2are standard error of F
1and F
2respectively 1
21
F
FF dSE
FF
21 2
2
2
1SESE

10. Dr.K. Saravanan, GPB, AU
•Theestimationofheterosisandinbreedingdepressiontogetherprovideinformation
aboutthetypeofgeneactioninvolvedintheexpressionofvariousquantitative
traits.
1.Ifhighheterosisiffollowedbyhighinbreedingdepression,itindicatesthepresenceofnon–
addivitvegeneaction.
2.Ifheterosisisfollowedbylowinbreedingdepression,itindicatespresenceofadditivegene
action.
3.Theheterosiswillbehighwhensomeallelesarefixedinoneparentandotherallelesinthe
otherparent(dispersionofalleles).
4.TheGeneswithlackofdominancewillnotexhibitheterosisinF
1butmayshowincreasein
performanceinF
2(lowinbreedingdepression)duetofixationofgenesi.e.,additivegene
action.
Heterosis, Inbreeding Depression & Gene action

11. Dr.K. Saravanan, GPB, AU
Problem
Atotalof15cottonhybridsandtheirparentswasevaluatedinaRBDwithfourreplications.The
followingisthedataonyieldingms.Workouttheheterosispercentonallthethreebasesandcommentonthe
results.AssumeP3isthestandardcheck.
Genotype R I R II R III R IV Total Mean
P
1x P
6 64.4 60.8 51.0 58.0 234.2 58.55
P
2x P
6 91.8 89.2 98.8 92.7 372.5 93.13
P
3x P
6 38.1 48.2 42.5 45.8 174.6 93.65
P
4x P
6 54.1 55.6 62.7 61.7 234.1 58.53
P
5x P
6 74.2 85.3 78.8 84.5 322.8 80.70
P
1x P
7 86.9 81.4 75.8 70.4 314.5 78.63
P
2x P
7 99.8 88.2 83.3 92.3 363.6 90.90
P
3x P
7 109.2 102.3 108.2 104.5 424.2 106.05
P
4x P
7 99.7 106.5 112.8 110.9 429.9 107.48
P
5x P
7 105.2 106.7 97.9 111.4 421.2 105.3
P
1x P
8 54.4 60.8 64.8 64.1 244.1 61.03
P
2x P
8 53.9 48.3 50.6 54.6 207.4 51.85
P
3x P
8 93.5 93.1 89.2 83.8 359.6 89.90
P
4x P
8 81.4 79.8 82.8 83.7 327.7 81.93
P
5x P
8 88.6 94.2 90.8 96.2 369.8 92.45
Geno R I R II R IIIR IV TotalMean
P
1 64.4 56.2 62.9 59.3 242.860.70
P
2 96.9 91.4 83.8 88.4 360.590.13
P
3 95.8 99.3 96.2 99.4 390.797.68
P
4 62.4 70.8 73.8 69.8 276.869.20
P
5 81.5 72.8 89.8 83.7 327.881.95
P
6 53.2 60.6 61.6 56.8 232.258.05
P
7 93.2 99.7 90.2 99.4 382.595.63
P
8 85.3 89.6 79.4 84.3 338.684.65
Total 1827.91840.81827.71855.77352.1

12. Dr.K. Saravanan, GPB, AU
ANOVA

13. Dr.K. Saravanan, GPB, AU

14. Dr.K. Saravanan, GPB, AU
Genotype Mean
P
1x P
6 58.55
P
1 60.70
P
6 58.05
P
3 97.68
P
1x P
6

15. Dr.K. Saravanan, GPB, AU
Test of significance

16. Dr.K. Saravanan, GPB, AU
Hybrid
Relative
heterosis
t value Heterobeltiosis t value
Standard
heterosis
t value
P
1xP
6 -1.40 0.28 -3.54 0.63 -40.06* 11.38
P
2xP
6 25.70* 6.39 3.33 0.87 -4.66 1.32
P
3xP
6 20.37* 11.49 -4.12* 15.71 -4.12* 15.71
P
4xP
6 -8.02 1.71 -15.42* 3.10 -40.08* 11.38
P
5xP
6 15.29* 3.59 -1.53 0.36 -17.38* 4.91
P
1xP
7 0.59 0.15 -17.78* 4.94 -19.50* 5.54
P
2xP
7 -2.13 0.66 -4.95 1.38 -6.94 1.97
P
3xP
7 9.71* 3.15 8.57* 2.43 8.57* 2.43
P
4xP
7 30.41* 8.41 12.39* 3.44 10.03* 2.85
P
5xP
6 18.59* 5.54 10.11* 2.81 7.80* 2.22
P
1xP
8 16.03* 3.91 -27.90* 6.87 -37.52* 10.65
P
2xP
8 -40.67* 11.93 -42.47* 11.13 -46.92* 13.32
P
3xP
8 -1.39 0.43 -7.69* 2.26 -7.96* 2.26
P
4xP
8 6.50 1.68 -3.21 0.79 -16.12* 4.58
P
5xP
6 10.98* 3.07 9.21* 2.27 -5.35 1.52
Results :
P1 X P6
t value for di = 0.28
t value for dii = 0.63
t value for diii = 11.38
Tabulated‘t’valueat5%fordf
66=1.997

17. Dr.K. Saravanan, GPB, AU
Hybrid
Relative
heterosis
t value Heterobeltiosis t value
Standard
heterosis
t value
P
1xP
6 -40.06* 11.38
P
2xP
6 25.70* 6.39
P
3xP
6 20.37* 11.49 -4.12* 15.71 -4.12* 15.71
P
4xP
6 -15.42* 3.10 -40.08* 11.38
P
5xP
6 15.29* 3.59 -17.38* 4.91
P
1xP
7 -17.78* 4.94 -19.50* 5.54
P
2xP
7
P
3xP
7 9.71* 3.15 8.57* 2.43 8.57* 2.43
P
4xP
7 30.41* 8.41 12.39* 3.44 10.03* 2.85
P
5xP
7 18.59* 5.54 10.11* 2.81 7.80* 2.22
P
1xP
8 16.03* 3.91 -27.90* 6.87 -37.52* 10.65
P
2xP
8 -40.67* 11.93 -42.47* 11.13 -46.92* 13.32
P
3xP
8 -7.69* 2.26 -7.96* 2.26
P
4xP
8 -16.12* 4.58
P
5xP
6 10.98* 3.07 9.21* 2.27
Results :
The hybrids P3X P7, P4 XP7 and
P5 XP7and excelled other hybrids
by recording significantly superior
heterosison all the three bases.

18. Thank q
Dr.K. Saravanan, GPB, AU