Mating design is a schematic cross between the groups or strains of plants are made in a plant breeding that is common in agriculture and biological sciences Analysis of variance in offspring  plants results from a mating design To evaluate the effects of additive, dominance ,and epistasis and heritability value equal to the value of genetic expectations

1. TOPIC – TOP CROSS MATING DESIGN
SUBMITTED TO
Dr. M. P. Patel
Course : GP 504
Assistant Research Scientist
Regional Research Station
AAU, Anand
SUBMITTED BY :
Boddu Sangavi
Reg : 2010120093
M.sc agriculture 2ndsemester
Genetics and plant breeding
DATE OF SUBMISSION – 19.06.2021

2. CONTENTS :
 Mating Design
 Top Cross Mating Design
 Characteristics Of A Tester
 Planting Of Parents
 Mating Scheme For Top Cross Mating Design
 ANOVA For Half Sib Family
 Test Effecting Crosses And Evaluation
 Applications Of Top Cross
 Merits and Shortfalls
 Top-cross Hybrid and production of top cross seed
 Case studies

3. MATING DESIGN
• Design is a logical structure of an experiments, field plan
to conduct an experiment
• Mating design is a schematic cross between the groups
or strains of plants are made in a plant breeding that is
common in agriculture and biological sciences
DESIGN
MATING DESIGN ENVIRONMENTAL DESIGN

4. OBJECTIVES:
 To obtain information and understand the genetic control
of a trait or behavior that is observed, and
 To get the base population for the development of
plant cultivars
 Analysis of variance in offspring plants results from a
mating design
 To evaluate the effects of additive, dominance ,and
epistasis and heritability value equal to the value of
genetic expectations

5. FACTORS AFFECTING THE CHOICE OF MATING DESING
 Type of crossing to be used (Artificial or natural)
 Type of pollination (Self or cross pollinated)
 Type of pollen dissemination (Insect or wind),
 The purpose of project (For genetic or breeding studies)
 The presence of male sterility system and
 The size of population required

6. TOP CROSS MATING DESIGN:
• Top cross refers to a mating design between a selection line , clone and
a common pollen parent which may be a variety ,inbred line or single
cross
• The selected parents are crossed with common tester of known
performance generally in open pollination
• The design was proposed by jenkins and brunsen in 1932 for testing
inbreeding lines of maize in cross bred combinations
• Later renamed top cross by tysdal and grandall in1948(hill et al., 1998)
• It is also called inbred-variety cross (Sleper and Poehlman, 2006).
• It is a one factor design

7. Inbred Open pollinated
variety
Top cross
progeny

8. • The tester serves as the male parent while the lines or clones to be
tested serve as females
• Top cross has been fairly widely used for preliminary evaluation
of combining ability of new inbred lines (Mosa, 2010).
• In top cross, the progenies from individual plants are tested; these
progenies are half-sib families.
• Top crosses require 5 heads per cross; this number is necessary
because these crosses will segregate in the next F1 generation and
at least 80 plants to facilitate the selection of desirable plants in the
F1
• The possible numbers of crosses are n x 1,
given n = number of inbreds

9. CHARACTERISTICS OFA TESTER
The most desirable tester is one which provides maximum information
about the performance of a line in cross combinations under different
environmental conditions (Allard, 1960).
Wide adaptability Low yield potential
Low performance for
other traits
GOOD
TESTER
Broad genetic
base

10. COMMONLY USED TESTERS
1.Inbred Lines : The testers most commonly used today for
the first evaluation combining ability of a line are inbreds
with which it would most likely be crossed to produce a
commercial hybrid.
2. Single Cross Hybrid : In sugar beet, three-way cross
hybrids single cross hybrids are used to test combining
ability to produce commercial cultivars.
3. Parent of Current Cultivars: Parents of current cultivars
are used to provide god information about the general
combining ability of a line with other potential parents.

11. INBRED
LINES
SINGLE
CROSS
HYBRID
most likely be crossed to produce a commercial
hybrid.
In sugar beet, three-way cross hybrids single
cross hybrids are used
PARENT OF
CURRENT
CULTIVARS
provide god information about the GCA of a
line with other potential parents.
COMMONLY
USED
TESTERS

12.  As a common tester is used for all crosses, all progeny
families produced are half-sibs
 Top cross mating design permits the evaluation of GCA
for the group of lines, clones, or selections involved in the
crosses.
 It is mainly used in cross-pollinated crops such as maize
where it is commonly an inbred-cultivar cross.
 Additionally, the design is used for initial evaluations
of breeding potentials in new maize accessions (Stuber,
2004).

13. PLANTING OF PARENTS:
• Planting of parents should be adequate for the effective Top crossing
• The ratio of number of male rows to female rows varies with species;
 It may be necessary to delay planting dates if the male and female
parents differ in days to flowering.
CROP MALE ROWS FEMALE ROWS
Maize 2 6
Sugar beet 1 1
Castor 2 10/12

14.  If wind is a factor in pollen dissemination, tester
rows should be planted perpendicular to prevailing
winds.
 If isolation is not possible, the tester may be planted in
paired rows with the materials to be evaluated.
 Hand pollinations are made between rows and the tester
may be used as either the male or the female parent.
 Replication and randomization of the female
genotypes may help to minimize the effects of inter-
crossing among females (Stuber, 2004).

15. MATING SCHEME FOR TOP CROSS MATING DESIGN
A x tester TCA
B x tester TCB
C x tester TCC
D x tester TCD
E x tester TCE
F x tester TCF
.
.
.
.
n x tester TCn

16. TESTER
A
B
C
n
D
E
TCA
TCB
TCC
TCD
TCE
TCn
selected
parent
Top cross
progeny
Open
pollination

17. ANOVA FOR HALF SIB FAMILY TEST
SOURCE df MS EMS VARIANCECOMPONENTS
Progenies g-1 M1 σ2e +rσ2prog σ2prog=cov(HS)=(1+F) σ2A
Blocks r-1 M2 -
error (g-1)(r-1) m3 σ2e σ2e =σ2
Total (rg-1)
• The covariance within the families is cov(HS)= (1+F) σ2
A
• The variance component σ2
prog is an estimate of (1+F )σ2
A , calculated from
σ2
prog = v(m1)+ v(m2 )
when the parents are non-inbred, F = zero
when the parents are inbred, F = 1.
Where F the inbreeding coefficient of the genotypes is tested
4
4
4

18. EFFECTING CROSSES AND EVALUATION
Using a single wide based tester variety as pollen parent and
n test inbreds as female parents, single crosses are made to
develop n number of crosses.
These crosses along with inbreds are evaluated in any
standard design (say RBD) with required number of
replications
Data on quantitative characters are obtained for each of the
genotypes in all the replications

19. APPLICATIONS OF TOP CROSS
• Davis 1927 was the 1st to suggest the usage of inbred variety cross or
top cross as a method of evaluating inbred lines.
• The inbreds involved in the best crosses might carry adequate fixable
genetic variance so as to produce better hybrids with number of other
inbreds. Such inbreds possess high breeding value for the trait in point
• Jenkins and Brunson 1932 obtained significantly high correlation
coefficients between the mean performance of inbreds for several
agronomic characters in simple crosses and in the performance of the
same lines in top cross
• They suggested that top cross can be used to eliminate undesirable
material in the early stage itself

20.  In recent times, it become necessary to test the combining
ability of the materials at early generation itself to quicken
the breeding process
 Therefore the early generation materials ( f4 and f5 stage
i.e., before attaining the stage of inbred ) may also be used
for crossing with an open pollinated variety or inbred
whose broad genetic base was already established
 The line × tester design is an extension of the top cross
design. Instead of using one tester (top cross), more than
one tester is used

21. MERITS:
 Top cross has been fairly widely used for preliminary evaluation of
combining ability of new inbred lines
 It is a simple and efficient system of screening inbred lines for
combining ability before pairing inbreds in single-cross yield trials.
 This design is probably the simplest model of mating design that can
provide preliminary rapid screening of genetic stocks as it involves
the lowest crossing load and simple statistical analysis
 Conventionally, half sibs are developed from individual maternal parent.
However, paternal parents could be identified using DNA fingerprinting
and parentage analysis.
 useful in determining variance components, GCA and heritability.
 The variance components and GCA are determined from the average
performance of the progenies of individual maternal parents.
 Variations measured in a progeny are partitioned into within and
between maternal parents

22. SHORTFALLS:
 A single tester variety may not offer wide genetic background
for testing the inbred stocks.
 Top cross progenies yield only GCA information, not SCA
 Insufficient statistics to estimate all genetic parameters, expected
genetic gains are reduced by half since the components of variance are
estimated from maternal half sibs;
 Environmental variability greatly influences flowering and
performances of the parents and progenies possibly due to their
diverse origins and heritability of traits

23. Top-Cross Hybrid
• It is a crossing between an open-pollinated variety (OPV)
and an inbred line (OPV x A ).
Advantages
• Use of an open-pollinated variety as a female produces
plenty of seed and thus reduces the cost of production and
price of seeds to growers
• The inbred parent harvested from detasseled production
field can be used as a male parent, allowing the seed
company to multiply only the female parent in a separate
field.
Disadvantage
• The hybrid is not very uniform for the different traits

24. PRODUCTION OF TOP-CROSS SEED:
• This scheme is also known as inbred-variety cross, (Inbred x
Variety), i.e., inbred line is crossed with an open pollinated variety
• Also the cross between a single cross and with another inbred is
known as double top cross or 3 ways cross.
• This method is used not only for developing a hybrid but to test the
combining ability of the inbred.
• The variety or the single cross product is used as male parent and
the inbred line to be tested is used as female parent (emasculated),
the seeds from the inbred line are harvested.

25. • Generally, top cross hybrids are extra productive than open-pollinated
varieties (OPVs) and are expected to increase production per unit area,
which is the primary objective in maize breeding programs.
• The cost of producing top cross hybrids is comparatively cheaper than
conventional hybrid seeds (Bidinge et al., 2005).
• From research findings, the decline in grain yield due to recycling top
cross hybrid seed is half of that of conventional hybrids yet they equate
well with respect to grain yield (Pixley and Banziger, 2004).
• The effect of planting “recycled” or second generation seed was
insignificant for OPVs (5%), rigorous for hybrids (>30% yield loss)
and intermediate for top cross hybrids (16% yield loss).
• Since many farmers in Ghana recycle their seeds, the use of non-
conventional top cross hybrids could be one approach of enhancing
yield levels

26. I. Correlation and path coefficient analysis of top-cross and three-way
cross hybrid maize populations
II. Top cross analysis of S7 maize lines to evaluation combining ability
of some agronomic traits
III. Selection of maize top-crosses for different nitrogen levels through
specific combining ability

27. MATERIALS AND METHODS
The 20 hybrids comprising 10 top-cross and 10 three-way cross hybrid varieties,
used for this study were collected from the Genetic Resources Centre (GRC) of
the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria. Field
experiments were conducted during the 2014 cropping season at three diverse
environments of South-Western Nigeria: The trials were laid out in randomised
complete block design with three replications.

29. CONCLUSIONS
• From the study, field weight in both hybrid populations, number of kernel
rows per cob, ear diameter and ear height in the top-cross hybrids, as well as
ear length and 100-grain weight in the three-way cross hybrids were directly
correlated with grain yield.
• These traits can be used as the main criteria for grain yield improvement in
the respective hybrid populations. Some traits showed similar direct effects
in both hybrid populations, but the link between direct and indirect effects
on grain yield depends on hybrid population.

30. TOP CROSS ANALYSIS OF S7 MAIZE LINES TO EVALUATION
COMBINING ABILITY OF SOME AGRONOMIC TRAITS
Mehdi Rahimi1)* and Farhad Sadeghi2)
Abstract: In order to investigating combining ability of the inbred lines for grain
yield and other traits, 10 F1 hybrids of maize with the 10 S7 parental lines and a
control cultivar were studied in a randomized complete block design at
Kermanshah Mahidasht stations in 2013. The yield and its component traits were
measured. Analysis of variance showed significant differences in most traits
measured at 1 %. Comparison of the mean showed significant differences
between the hybrids were much greater than that resulted in lines. To screen good
combination and high yield, top cross analysis showed, that the combination of
production lines, KLM80039, KLM80043, KLM80044, KLM80049 and
KLM80001 with the MO17 tester has a particular superiority and also was
identified as high-performance genotypes and yield components to comparison
with control varieties (704). This study suggested that the hybrids KLM80026 ×
MO17, KLM80039 × MO17, KLM80043 × MO17, KLM80049 × MO17 and
KLM80001 × MO17 were promising single cross hybrids and could be used in
the maize breeding program. Keywords: Maize, Tops Cross, Yield and yield
components

31. Materials and Methods
In this study, 10 lines (KLM 80019, KLM 80026, KLM 80027, KLM 80035,
KLM 80036, KLM 80039, KLM 80043, KLM 80044, KLM 80049 & KLM
80001) were used. These lines were selected at S7 stage of the 730 lines in two
early stages and tested according to screening populations based on the criteria
of moisture stress tolerance and high yielding.

32. CONCLUSION
• In the current investigation, SCA represent a mainly dominance effect (additive ×
dominance, dominance × dominance effects).
• The crosses showing SCA effects that involved parents with good GCA could be
exploited. However, if a cross of high SCA has parents of which one is good combiner
and another as poor or average combiners, such crosses are likely to throw some good
segregates. Moreover, if the additive genetic system is presently in a good general
combiner and epistatic effects on the cross, then act in the same direction so as to
maximize the desirable expression of the characters in question.
• This study suggested that the hybrids combination KLM80026 × MO17,
KLM80039 × MO17, KLM80043 × MO17, KLM80049 × MO17 and
KLM80001 × MO17 were promising single cross hybrids having a
parental combination of high × high, high × low GCA and their effects
could be used for the improvement of parental lines for desired
characters by selecting in advanced generations.

33. • Top-cross hybrids were obtained from two isolated cross fields, where the
lines were intercalated with the testers. Two testers (T1, commercial single
hybrid with good yield potential; and T2, equal mixture of S1 progenies) were
used.
• Top-cross hybrids were obtained during the 2011/2012 harvest.
• We obtained 110 hybrid progenies, called top-crosses, which were used in the
evaluation trials together with the five base populations and six controls.

34. MATERIAL AND METHODS
• Five base populations were evaluated, from which partially inbred lines were
extracted
• Of these, 11 partially inbred S1 progenies were extracted from each base
population using the self-fertilization method, as described by Borém
(2009)Borém, A. (2009). Hibridação artificial de plantas. Viçosa, MG: Editora
UFV.
• In each population, 100 S0 plants were selected, based on vigor and type, and
later self-fertilized, with only upright plants being harvested. In each
population, the top 11 S1 lines were selected to be evaluated in top-cross.
• The process of self-fertilization of the plants was carried out during the 2011
off-season.
• The controls used were the BR 106 variety and BRS 1010, XB 9003, XB 8010,
DKB 390 and Omega hybrids, in addition to each of the populations initially
used.
• To evaluate the grain yield (GY, kg∙ha-1), the ears of the central rows were
harvested manually and threshed to determine the grain weight and humidity,
correcting the humidity to 13%.

35. The joint analysis of variance was performed according to the statistical model
CONCLUSION
• The mean grain yield of the 11 hybrids selected by the highest SCA estimates
for high and low N was higher than the controls mean in approximately 330
and 241 kg∙ha-1.
• These results demonstrate that the selection for each environment was efficient
and reveals the possibility of developing new hybrids for the Brazilian Cerrado
region.

36. References:
• Quantitative genetics and biometrical techniques un plant breeding by n.nadarajan ,
n.manivannan . m. gunasekharan
• Sharma JR. Statistical and biometrical techniques in plant breeding. 1 ed. New Age
International. New Delhi, India. 2006;433 p]
• Falconer DS, Mackay TFC. Quantitative genetics. 4th ed. Longman group Ltd. UK.
1996
• J. Plant Breed. Genet. 01 (03) 2013. 117-129 ,Journal of Plant Breeding and Genetics
ISSN: 2305-297X (Online), http://www.escijournals.net/JPBG
• MATING DESIGNS: HELPFUL TOOL FOR QUANTITATIVE PLANT BREEDING
ANALYSIS a,bAthanase Nduwumuremyi*, aPangirayi Tongoona, cSlyvestre Habimana
• AJCS 14(12):1855-1869 (2020) ISSN:1835-2707 doi: 10.21475/ajcs.20.14.12.p2588
Mating designs commonly used in plant breeding: A review
Jane Muthoni1*, 2, Hussein Shimelis2
• African Journal of Agricultural Research
• Science direct
• Aslam, M., Khan, I. A., Basra, S. M. A. (2012) Combining ability estimates and some
mode of inheritance for droughtrelated traits in genetically distant maize accessions
(Zea mays). The Journal of Animal & Plant Sciences 22 (3):679-682.

37. THANK YOU