Rice “Fingerprints” Provide Valuable Information to Rice Breeders
They say that fingerprints have a lot to say about a person. In fact, recent discoveries show that inferences on personality can be derived from the fingerprint. Fingerprinting, however, is not solely done in humans. Genetic fingerprinting is now a major technique in crop biology research.
In the paper “Genetic fingerprinting: Advancing the frontiers of crop biology research,” Dr. Gabriel O. Romero, Cheryl Adeva, and Zosimo Battad II documented how Filipino scientists seize the benefits of DNA fingerprinting in crop research.
Fingerprinting is used to characterize a DNA, which contains the traits of an organism. Through fingerprinting these traits are revealed, helping the breeders select the traits that they can use in their breeding activities.
DNA fingerprinting was such a tedious process before. But the discovery of the polymerase chain reaction (PCR) has paved the way for a more convenient analysis of DNA variation. PCR magnifies a section in a DNA, making it possible for scientists to study and/ or characterize that area. Scientists are now using markers, which are specific DNA sequence attached to a trait. The use of these markers makes assaying a lot more convenient as the presence of a marker signifies that a trait is present.
Tax identification and phylogeny, diversity analysis, hybridity testing, gene mapping, marker-aided introgression, somaclonal variation, and patenting are some of the areas where genetic fingerprinting is useful.
Through genetic fingerprinting, scientists can tell sequence of events involved in the development of a rice plant. Information such as this can give inferences on traits of a variety. Say for example, through genetic fingerprinting, it can be learned that PSB Rc28 is one of the parents of PSB Rc82.
Varieties always interest farmers. While seeds may thrive in different conditions, there are just a few that can deliver the highest yield given challenging environments. Varietal recommendation, therefore, is crucial.
Genetic fingerprinting is useful in diversity analysis by measuring the level of genetic similarity or differences among materials. Decoded traits of a variety are good inputs in rice breeding. This will guide the breeders in selecting the traits that they can transfer to another variety.
Moreover, genetic information provides good input in conservation. There are germplasms requiring stringent measures for conservation. Genebanking is very important to maintain a repository of the varieties so that at the advent of environmental woes such as pests and diseases, there would be ready substitutes for farmers.
In making hybrid rice varieties where 50:50 parental contributions is crucial, genetic fingerprinting is very useful. Scientists say that proper identification and selection is crucial for “proper identification and varietal protection, (genetic identity stability, complete characterization and measurement of crop genetic diversity, and for uniformity of appearance and agronomic performance of produced variety that will meet the demand of the farmers and consumers.”
Genetic fingerprinting gives precise results, minimizing mistakes in the breeding process. It is also useful in gene mapping or in determining the location of a trait, a requisite for any biotechnology activities.
In plants, as in humans, there are recessive and dominant traits. Recessive traits are those that will be expressed later. Hence, if the physical appearance will be the sole basis for some traits possessed by a rice plant, that will not be very accurate. But through the use of markers, the recessive genes get noticed, making it possible for scientists to select properly the traits that they can cross even when those traits will be expressed later in the life of the plant.
Tubigan 7 (NSIC Rc 142) and Tubigan 1 L(NSIC Rc154) are the first two products of marker-aided selection. They have resistance genes Xa4 and Xa21 against bacterial leaf blight.
Somaclonal variation, meanwhile, refers to the variations seen in plants via plant tissue culture. The variations may be in the form of mutation such as alteration of cell ability to repair damaged and mutated DNA.
Somaclonal variation is being used today to breed varieties that can live in drought-prone areas. The team is led by Dr. Nenita V Desamero and NC-2 and IVC-21 are the first two products of somaclonal variation in rice breeding that qualified in the National Cooperative Trial.
Genetic fingerprinting can strengthen the claims for patenting rice varieties. Although the physical appearance of varieties cannot exactly express the distinction between two almost similar varieties, through genetic fingerprinting, the traits within the variety can be seen, and hence, the claim of plant breeders is strengthened.
By Jaime A. Manalo IV