Cereals processing technology

94 Cereals processing technology
foods we eat contain some type of GMO. In a 1995 survey of consumer
opinions, only 22% of Austrians and 30% of Germans said ‘yes’ when asked if
they would be likely to purchase a food modified by biotechnology to resist
insect damage. The penetration of GM foods into the agricultural-input (seed)
industry and their adsorption by growers have been quite rapid. Around the
world the increase in acreage devoted to GM crops increased from 4.3 million
acres in 1996 to 69.5 million acres in 1998.
Seventy-one percent of the transgenic crops have been engineered to tolerate
herbicides, and 28% to resist insects. These modifications have benefited
farmers by reducing risk and increasing profit. They help reduce the use of
chemical insecticides and herbicides. Through newer biotechnological methods,
use of GM crops has resulted in higher yields because loss of crops to pests in
the field has been reduced, and cleaner, higher-grade end products have been
produced for the market.
Genetically-modified (GM) foods are protected on several grounds, and
everyone in the food supply chain, from seed manufacturers to retailers, will
need to accommodate consumer demands in some fashion. The burden of proof
is on the scientific community and on the producers and manufacturers of food
products to establish the safety of GMOs. It is a new era of innovation in food
production. Molecular genetic studies of rice have accelerated rapidly due to the
favorable qualities of rice, including its small genome size and ease of
transformation. Redona and Mackill 25 studied molecular mapping of quantitative
trait loci in japonica rice. A linkage map of 129 random amplified
polymorphic DNA (RAPD) and 18 restriction fragment length polymorphism
(RFLP) markers was developed using 118 F2 plants derived from a cross
between two japonica cultivars with high and low seedling vigor, Italica livarno
(IL) and Labelle (LBL), respectively. The map spanned 980.5 cM with markers
on all 12 rice chromosomes and an average distance of 76 cM between markers.
Codominant (RFLP) and coupling phase linkages (among RAPDs) accounted
for 79% of total length and 71% of all intervals. This map contained a greater
percentage of markers on chromosome 10, the least marked of the 12 rice
chromosomes, than other rice molecular maps, but had relatively fewer markers
on chromosomes 1 and 2. The authors used this map to detect quantitative trait
loci (QTL) for four seedling vigor related traits on 112 F3 families in a growth
chamber slantboard test at 18ºC. Two coleoptile, five root, and five mesocotyl
length QTLs, each accounting for 9–50% of the phenotype variation, were
identified by interval analysis. Single-point analysis confirmed interval mapping
results and detected additional markers significantly influencing each trait.
About two-thirds of alleles positive for the putative QTLs were from the highvigor
parent, IL. One RAPD marker (OPAD 13720) was associated with a IL
allele that accounts for 18.5% of the phenotype variation for short length, the
most important determinant of seedling vigor in water-seeded rice. Results
indicate that RAPDs are useful for map development and QTL mapping in rice
populations with narrow genetic base, such as those derived from crosses among
japonica cultivars. Other potential uses of the map are discussed.