Agriculture Reference
In-Depth Information
hybrids for marketable quality, disease (pink root) resistance and yield, the
latter mainly because the hybrids produced more bolters (Cramer, 2001).
However, this difference may simply reflect the importance of selection for local
adaptation with onions, since many of the OP varieties tested derived from a
long-standing programme of breeding OP cvs at New Mexico State University,
and the hybrids were from California-based breeders.
Part of the attraction of hybrid cultivars lies in the control that the breeder
and seed producer maintains over them: they cannot be reproduced from
farmer-saved seed, so the work invested in their development cannot be pirated.
On the other hand, low and erratic seed yields have sometimes made hybrid
cultivars unavailable and seeds of hybrids are two or three times the price of OPs
(Cramer, 2001). Also, hybrids take a long time to develop and need sophisticated
breeding and seed production facilities. The genetic base of hybrid cultivars is
narrow and they contain less genetic variability than open-pollinated cultivars,
so they may be less adaptable in abnormal, stressed conditions (Pike, 1986).
For all of these reasons they are not necessarily the best route to crop
improvement, particularly in some of the poorer, tropical countries where
there is great need for onion improvement. In these countries, as well as in
wealthier temperate regions, old, open-pollinated varieties are being replaced
by newer ones, often hybrids, from transnational seed companies (Currah and
Proctor, 1990). The old varieties were often perpetuated by farmer-saved seed.
The same trends have been noted for Japanese bunching onion varieties in
Japan and for leeks in Europe (de Clercq and van Bockstaele, 2002).
As pointed out previously, it is important that the genetic diversity
represented by the traditional varieties is conserved and not lost. These
tendencies in allium crop breeding are typical of the situation in many crops.
There is an interesting and ongoing debate centred on whether the commercial
interests directing crop breeding correspond with long term public interests,
particularly those of the poorer fraction of the world's population (Mooney,
1979). Partly as a result of this debate, various publicly and charitably funded
agencies are involved in the genetic conservation of allium crops coordinated
by the International Board for Plant Genetic Resources (Astley, 1990). It is
apparent, then, that many possibilities and conflicts arising from the new
biotechnologies, the globalization of breeding and seed production companies
and the geopolitical debate on the conservation and use of genetic resources
are well illustrated by trends in allium breeding and seed marketing.
