Principles of Plant Genetics and Breeding

PERFORMANCE EVALUATION FOR CROP CULTIVAR RELEASE 427
Exp. Number 84HT01 2004 WHEAT HEADROWS
Seed Source Cross Gen Parent Lines Code Plot No
Check variety = Redcoat ****** 101
83GH01 4 T830001 F1 FRANKENMUTH/AUGUSTA PMHFLR 102
83GH01 4 103
83GH01 6 T830002 F1 CALDWELL/AUGUSTA//HOUSER LRPM 104
83GH01 6 105
Figure 2 Output of a plant breeding book generated with BRSERIES in MSTAT.
The use of MSTAT strengthens plant breeding programs in several ways: (i) by quickly and accurately designing yield trials and
other experiments; (ii) by enabling breeders to maintain better records; (iii) by increasing the size of the breeding programs
because of the ease of information handling; (iv) by creating books with information collected over several seasons; and (v) by
analyzing experimental data over multiple locations and years. MSTAT helps to improve the efficiency, timeliness, and
confidence of conclusions that are all very important concerns for plant breeders.
interaction (AMMI). These procedures were discussed
in Chapter 7.
Adaptation
According to P. M. A. Tigerstedt, in the context of
evolutionary biology, adaptation is a process, adaptiveness
is the level of adaptation of a plant material to an
environment, while adaptability is the ability to show
adaptiveness in a wide range of environments. However,
according to Cooper and Byth, in a plant breeding
context, adaptation and adaptiveness relate to a condition
rather than a process. They indicate the ability of a
plant material to be high yielding with respect to a
specific environment, one to which it is adapted. One
of the purposes of a G × E analysis is to help breeders
decide whether to breed for narrow or wide adaptation
or adaptability. Breeding for narrow adaptability, the
breeder’s goal is to release a cultivar for a specific part
of the target region (with a unique set of conditions),
whereas in breeding for wide adaptability, the breeder
focuses on releasing a cultivar with high performance
across all environments.
As previously stated, only a G × location interaction
is useful for determining genotype adaptation patterns
in an ANOVA analysis. Further, only repeatable G ×
location interactions are of practical importance. However,
if the G × location variance is small in magnitude
compared to other sources of variance, even though
significant, it minimizes the specific advantage for
breeding for narrow adaptation.
Field plot technique in plant breeding
The subject of field plot technique deals with decisionmaking
processes and other activities conducted by the
plant breeder to fairly and effectively evaluate genotypes
from a breeding program, to select cultivars for release.
Field trials are designed to evaluate genotypes in a
natural environment that is similar to that which farmers
operate in. To evaluate the genetic potential of genotypes,
they must be grown in an identical environment
so that any observed differences can be attributed to
the genotype not chance variations. Unfortunately,
outside a controlled environment condition such as a
greenhouse, it is impossible to find a truly homogeneous
environment in the field. One of the goals of the field
plot technique is to evaluate genotypes error free (or,
in practice, with a minimum error). It is important,
therefore, to identify the source of error in a field study.
In order to collect data in the proper manner for analysis
and decision-making, the breeder should follow a
set of statistically based rules for laying out an experiment
in the field, called the experimental design. Such
a design not only allows the breeder to estimate random
error in the field but the choice of a good design can
minimize this error.
Sources of experimental error
In an experiment, a researcher may deliberately impose
conditions or factors that would generate variance in
outcomes; such a factor is called a treatment. The unit
to which a treatment is applied is the experimental