Agriculture Reference
In-Depth Information
1
Introduction
varieties. Private sector plant breeders tend to have a
more clearly defined goal, developing new cultivars and
doing it as quickly as possible. In addition, many pri-
vate breeding organizations are, or are associated with,
agrochemical companies. As a result varietal develop-
ment may be designed to produce cultivars suitable for
integration with a specific production system.
Despite the apparent simple description of the breed-
ing process given above, in reality plant breeding
involves a multidisciplinary approach. Irrespective of
whether a breeding scheme is publicly or privately man-
aged, a successful plant breeder will require knowledge
in many (if not all) of the following subjects:
REQUIREMENTS OF PLANT
BREEDERS
The aim of plant breeding is to develop superior cul-
tivars, which are adapted to specific environmental
conditions and suitable for economic production in a
commercial cropping system.
The basic concept of varietal development is very
simple and involves three distinct operations:
produce or identify genetically variable germplasm;
carry out selection procedures on genotypes from
within this germplasm to identify superior genotypes
with specified characteristics;
Evolution It is necessary to have knowledge of past
progress in adapting crop species if additional advances
are to continue into the future. When dealing with
a crop species, a plant breeder benefits from knowl-
edge of the time scale of events that have modelled the
given crop. For example, the time of domestication,
geographic area of origin and prior improvements are
all important and will help in setting feasible future
objectives.
Botany The raw material of any breeding scheme
is the available germplasm (lines, genotypes, accessions,
etc.) from which variation can be generated. The biolog-
ical relationship, which exists within a species and with
other species, will be a determining factor indicating
germplasm variability and availability.
Biology Knowledge of plant biology is essential to
create genetic variation and formulate a suitable breed-
ing and selection scheme. Of particular interest are
modes of reproduction, types of cultivar and breeding
systems.
Genetics The creation of new cultivars requires
manipulation of genotypes. The understanding of
genetic procedures is therefore essential for success in
stabilize and multiply these superior genotypes and
release cultivars for commercial production.
The general philosophy underlying any breeding
scheme is to maximize the probability of creating, and
identifying, superior genotypes which will make suc-
cessful new cultivars. In other words they will contain
all the desirable characteristics/traits necessary for use
in a production system.
Plant breeders can be categorized into two types. One
group of plant breeders is employed within private com-
panies, while the other group works in the public sector
(e.g. government funded research institutes or univer-
sities). Private sector and public sector breeders have
different approaches to the breeding process. Many of
the differences that exist between public and private
breeding programmes are related to the time available
for variety release, types of cultivar developed and priori-
ties for characters in the selection process. For example,
breeders within the public sector are likely to have a
number of responsibilities, related to academic activ-
ities or extension services, as well as producing new
 
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