Transgenic Sunflower - Genetics, Genomics and Breeding of Crop Plants - page 301

popular than soybean alternatives. After the oil extraction process, the
residual sunflower meal has a low value as feed due to the limited level of
methionin, an amino acid that is also scarce in other plant products. The
Brazil nut ( Bertholletia excelsa ) is an exception to this general rule, providing
high concentration of this amino acid. Its genome has been biotechnologically
manipulated in order to improve its amino acid content (Marcellino et al.
1996) and enable it to be transferred to other species. Unfortunately, Brazil
nut albumen causes allergy in the natural product and also in GM soybean
expressing its traits (Lack 2002). Given that the Codex Alimentarius ( ftp://
ftp.fao.org/es/esn/food/guide_plants ) strongly recommends avoiding the
transference of genes that cause allergies, interest in this kind of product for
food purposes has declined. The situation for sunflower might, however, be
different because the main destination of its meal is animal feed.
Interest in procuring alternative sources of latex has led to a search for
increased biosynthesis in sunflower. The goal of this project, which has
been exclusively sponsored by a governmental organization, is to
commercially produce substitutes for USA imports. The guayule ( Parthenium
argentatum ) is a desert shrub that produces a variant of rubber, which does
not cause allergy and which therefore has a high economic value. Progress
in understanding the regulation of rubber biosynthesis in guayule has made
it possible to obtain GM plants that offer profitable yields (Cornish and
Scott 2005; Veatch et al. 2005). Such an annual crop should facilitate extensive
management, though at present transformation efficiency rates remain
extremely low (Cornish et al. 2007).
9.5 Debate about Transgenic Sunflower
Concerning the expansion of area devoted to transgenic crops in 2000, the
US National Sunflower Association pointed that sunflower was losing
acreage to other row crops, such as soybean and canola. Many farmers
found that hybrids of the former crops tolerant to glyphosate were easier to
manage, with less chemical usage and better crop quality and yields
( www.sunflowernsa.com ). Some seed companies (e.g, Pioneer, Advanta, Dow
Agroscience, and Monsanto) and public institutions (e.g., National Institute
of Agricultural Technology of Argentina, INTA) collaborated to accelerate
the release of sunflower GM varieties towards a more competitive crop, both
in the US and in Argentina. Most traits under field experimentation consisted
in Sclerotinia resistant, Lepidoptera resistant, and glyphosate tolerant
varieties. However, the high cost of the GM crop approval process by the
regulation offices (estimated in US$ 0.3-0.5 to 2 million in both countries),
plus an additional cost of US$ 5 million to obtain approval by the EU
countries—which is the main consumer market—(Fonseca et al. 2004)
seemed to hinder the effort. Sunflower would not return the investment as