The document discusses various breeding methods used in cross-pollinated crops. It describes population improvement methods like mass selection and modified mass selection that aim to increase the frequency of desirable alleles within a population. It also discusses hybrid varieties which are produced by crossing homozygous lines to create heterozygous populations. Additionally, it covers synthetic varieties which are created by either mixing equal amounts of seed from selected parental lines or allowing intercrosses between parental lines. Recurrent selection methods like recurrent selection for specific and general combining ability are also summarized that aim to improve the chances of developing superior inbred lines.

1. BREEDING METHODS IN CROSS
POLLINATED CROPS
Deva Ram
E-mail-mail2devhingra@gmail.com
DEPARTMENT OF GENETICS AND PLANT BREEDING
ALLAHABAD SCHOOL OF AGRICULTURE
SAM HIGGINBOTTOM INSTITUTE OF AGRICULTURE, TECHNOLOGY AND
SCIENCES

2. Selection method in cross
pollinated crops

3. Breeding methods in cross pollinated crops
Breeding methods
|
Population improvement Hybrid and
Synthetic
varieties
(Used to increase the (A variable no. of
frequency of desirable strains are crossed
alleles) to produced a hybrid
population)

4. Breeding methods in cross pollinated crops
Methods of population improvement
Breeding methods Breeding methods with
without progeny progeny test
Test
Eg:-(Mass selection) (Progeny test, Ear to
row method and
Recurrent selection)

5. Methods with cross-pollinating crops
 Intrapopulation improvement
1. Mass selection
2. Modified mass selection
3. Ear to row method
4. Modified ear to row method
5. Half sib selection
6. Modified half sib selection
7. Full sib selection
8. Recurrent selection
recurrent selection for sca
recurrent selection for gca

6. Methods with cross-pollinating crops
 Inter population improvement
1. Reciprocal recurrent selection

7. Breeding methods in cross pollinated crops
MASS SELECTION

8. Mass Selection
 Selection of individuals
 Sampling seed of selected
individuals to plant next
generation
 Oldest method of crop
improvement
 Improvement of
heterogeneous native
populations or landraces

9. Mass selection
 Mass Selection
 same form as with self-pollinated crops
 essentially a form of maternal selection since no
pollination control
 select desirable plants
 bulk seed
 repeat cycle
 with strict selection breeder will reduce population size
 slow genetic gain since lack pollination control
 must be able to ID superior phenotypes
 Not suitable for quantitative traits

10. MASS SELECTION
X X X X X X
X X X X X X
X X X X X X
X X X X X X
X X X X X X
X X X X X X
X X X X X X
X X X X X X
Grow population
Allow random mating
Harvest and bulk seed
from desirable plants
Plant new generation
Repeat
(Source: Tinker, 2008)

11. Mass Selection
 Higher percentage of desirable genotypes
 Method can only be used in environments where
trait is expressed - may not be suitable for off-
season winter nurseries
 Effectiveness is function of heritability
 Manage field to enhance differences: eg. irrigate
excessively to increase disease pressure

12. Mass Selection
Achievements :-
 Early varieties of bajra - Babapuri, Jamnagar giant, Pusa moti.
 Toria – increase the yielding ability by 30% and oil 56%, in Abohar.
 Rai – many early, erect to semierect types developed, Type- 11.
 Yellow sarson – T-42, T-16.
 Brown sarson – 17 dwarf, 17 medium, DS-1, DS-2.
 Maize – T-41, 19, Jaunpuri.
 Desi cotton – C-402, C-520.
 American cotton – 100F, 216F
 castor – B-1, B-4.

13. Breeding methods in cross pollinated crops
MODIFIED MASS SELECTION

14. Modified mass selection
 Also known as stratified mass selection or grid method of
mass selection.
 This modification is suggested by Gardner in 1961.
 Field is divided into several small plots, eg., having 40-50
plants each.
 Selection is done within the plots and not among the plots.
 Seeds are selected and composite to raise the next
generation.

15. Breeding methods in cross pollinated crops
EAR-TO-ROW METHOD

16. Ear-to-row method
Ear-to-row selection, generalized scheme (Source: Acquaah, 2006)

17. Breeding methods in cross pollinated crops
MODIFIED EAR-TO-ROW
METHOD

18. Modified ear-to-row method
1. First year. Plants selected on the basis of phenotype.
open pollinated seed from each plant harvested
separately.
2. Second year. Small progeny rows are grown and
evaluated. The remaining seed from the plants producing
superior progenies bulked to raise the next generation.
3. Third year. The bulked seed of 2 year planted and
allowed to open pollinate. Plants with superior phenotype
selected and seed harvested separately. The selection
cycle may be repeated one or more times.

19. Modified ear-to-row method
This modification of ear to row method was
widely used in breeding of maize in U.S.A.
and was responsible for the development of
several varieties.

20. Breeding methods in cross pollinated crops
RECURRENT SELECTION

21. Recurrent Selection
designed to increase the freq. of desirable genes
within a population
 developed in the 1940s for developing inbred
lines
 first suggested by Hayes and Garber in 1919
and independently by East and Jones in 1920.

22. Recurrent Selection
The schemes are divided into following four types:-
1. Simple recurrent selection
2. Recurrent selection for gca
3. Recurrent selection for sca
4. Reciprocal recurrent selection

23. Simple recurrent selection (Source: Acquaah, 2006)

24. Recurrent selection for sca & gca (Source: Acquaah, 2006)

25. Reciprocal Recurrent Selection
 Proposed by Comstock, Robinson, and Harvey
(1949) to select for both general and specific
combining ability
 General combining ability (GCA) is the ability
of a breeding strain to combine favorably with
many other strains or inbred lines. Analogous to
ADDITIVE gene action
 Specific combining ability (SCA) is the ability
of a genotype to combine favorably with one or
a few other genotypes. Analogous to
DOMINANT gene action

26. Reciprocal recurrent selection (Source: Acquaah, 2006)

27. Reciprocal Recurrent Selection
 Proposed by Comstock, Robinson, and Harvey
(1949) to select for both general and specific
combining ability
 General combining ability (GCA) is the ability
of a breeding strain to combine favorably with
many other strains or inbred lines. Analogous to
ADDITIVE gene action
 Specific combining ability (SCA) is the ability
of a genotype to combine favorably with one or
a few other genotypes. Analogous to
DOMINANT gene action

28. Reciprocal Recurrent Selection
 Although Recurrent and Reciprocal Recurrent
Selection methods were originally designed and
used to improve the chances of developing superior
inbreds of corn, these procedures are not used
explicitly in private industry for that purpose today.
 Most new inbreds in sorghum are developed
through pedigree or pedigree type procedures and
in corn doubled haploids procedure have become
popular since about 2000.

29. Breeding methods in cross pollinated crops
HYBRID VARIETY

30. Hybrid Production
Production of heterozygous populations from
the crossing of homozygous lines
Mostly used for cross-pollinated crops
The hybrid seed must be reproduced each year
The word HYBRID denotes a population of F1
plants derived by crossing inbred lines, clones,
open-pollinated varieties or any population that
are genetically dissimilar.

31. Hybrid Production
Steps involved
 Produce inbred lines
 Cross the inbred lines
 Single cross hybrid
 Harvest the female rows because they have the hybrid
seed
 Double cross hybrid
 Three way cross hybrid

33. Hybrid Production
Achievements:-
 First hybrid varieties in maize were released in 1961, viz.,
Ganga-1, Ganga-101, Ranjit & Deccan
 First hybrid bajra was developed by PAU. Ludhiana in 1965
as HB-1. Subsequently, HB-3 & HB-5 were released.
 Bajra – PHB-10, PHB-11, BJ-104 & BK-560.

34. Weaknesses
 Many years to provide a commercially
marketable seed.
 Crossing can only occur within the same
species, and often selection is inefficient
because it depends primarily on phenotypes.
 Finding the desirable trait takes large numbers
of crosses so space can be a premium.

35. Breeding methods in cross pollinated crops
SYNTHETIC VARIETY

36. Synthetic varieties
Steps involved in the production of synthetic
varieties:-
Step-1 Evalulation of lines for gca
 Topcross or polycross test for gca; outstanding lines
selected as parents.
Step-2 Production of the synthetic
Method 1. Equal seed from all the lines mixed and planted in
isolation. Open-pollinated seed harvested as the synthetic
variety(syn1)

37. Synthetic varieties
Method 2. The parental lines are planted in a crossing block.
All possible intercrosses are made. Equal seed from all the
crosses mixed to produced the synthetic variety (syn1).
Step-3 Seed multiplication
 Seed of the synthetic variety may be multiplied for one or
two generations before distribution.
 Open pollination in isolation (syn2 or syn3).

38. Synthetic varieties
Achievements:-
 Widely used in forage crops.
 Synthetic varieties have been developed in maize,
pearlmillet, sunflower, sugarbeet, alfalfa, lucerne and
several other crops in USA.
 In India, synthetic varieties have been developed in
pearlmillet at ICRISAT and in sugarbeet at Pantnagar
university.
 Sugarbeet – Pant synthetic-3
 Cauliflower – synthetic-3

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