Agriculture Reference
In-Depth Information
at least some plant breeders must be good at passing
on the essential information about the subject to future
plant breeders!
Information Technology
The science underlying
plant breeding is continually advancing, the agronomic
practices are continually being upgraded, the end-users'
choices change and the political context continually
affects agriculture. This means that it is vital that breed-
ers talk to these different groups of people but also use
what ever technology is available to keep up to date
on developments as they occur - or better before they
occur!
Psychic
The success of most plant breeding schemes
is not realized before many years of breeding and tri-
alling have been completed. It may be twelve or more
years between the initial crosses and varietal release.
Plant breeders therefore must be
crystal ball gazers
and
try to predict what the general public and farming
community will need in the future, what diseases will
persist twelve years ahead and what quality characters
will command the highest premiums.
it in this topic. Emphasis will be on the areas that are
most important from a plant breeding standpoint.
Knowledge of the evolution of a plant species can be
invaluable in breeding new cultivars. Studies of evolu-
tion can provide knowledge of the past changes in the
genetic structure of the plant, an indication of what
advances have already been achieved or might be made
in the future, and help to identify relatives of the domes-
ticated plant which could be used in interspecific or
intergeneric hybridization to increase genetic diversity
or introduce desirable characters not available within
existing crops.
Why did hunter gathers become farmers?
It is difficult to arrive at a firm understanding as to
why humans became a race of farmers. Early humans
are believed to have been foragers and later hunters.
Why then did they become crop producers? Farm-
ing is believed to have started shortly after the last ice
age. At that time there may have been a shortage of
large animals for hunters to hunt due to extinctions.
Indeed, little is known about the order of agricultural
developments. Did man domesticate animals and then
domesticate crops to feed these beasts, or were crops first
domesticated, and from this the early farmers found that
they could benefit from specifically growing sufficient
food to feed livestock? The earliest farmers may also
have been fishermen who tended not to travel continu-
ally and were more settled in one region. In this latter
case, perhaps the first farmers were women who took
care of the farming operation while the males fished
and hunted locally. It may simply have been that some
ancient people became tired of nomadic travel in search
of food, became bored with living in tents and opted
for a quiet life on the farm! The answers are not known,
although it can often be interesting to postulate why this
change occurred. One misconception about the switch
from hunting-gathering to farming is that farming was
easier. It has been shown that gathering food requires
considerably less energy than cultivating and growing
crops. In addition, skeletal remains show that the initial
farmers were smaller framed and more sickly than their
hunter-gatherer counterparts.
Irrespective of the reason which caused mankind to
cultivate crops, few would question that the beginning
of farming aligned with the beginning of what most of
In summary, therefore, successful plant breeders need
to be familiar with a range of scientific disciplines and
management areas. It is not, however, necessary to be
an expert or indeed an authority in all of these. How-
ever, greater knowledge of the basic science underlying
the techniques employed, and of the plant species con-
cerned, in terms of the biology, genetics, history and
pathology will increase the chances of a breeder succeed-
ing in developing the type of cultivars most suitable for
future exploitation.
EVOLUTION OF CROP SPECIES
Plant breeding consists of the creation and manipu-
lation of genetic variation within a crop species, and
selection of desirable recombinants from within that
variation. The process is therefore an intensification of
a natural process, which has been ongoing since plants
first appeared on earth. As soon as humans started carry-
ing out settled agriculture they effectively started plant
breeding. In this section the main features of crop plant
evolution will be covered briefly. The study of evolu-
tion is a vast and detailed subject in itself, and it will
not be possible to cover more than an introduction to
