Using nuclear science in marker-assisted plant breeding

Imagine you must identify a glass of seawater among a hundred glasses of drinking water merely by looking at them. Almost impossible. But what if the glass with the seawater had a small red dot, a marker, on it? You would solve the riddle in no time. Finding this marker is exactly what new developments in science now allow plant breeders to do. Plant breeders improve crops by using natural or artificially induced genetic variation to develop new traits. But they face enormous difficulties when integrating these improved traits into the varieties that farmers prefer. It's a process that requires a lengthy and cumbersome series of crosses, followed by testing and confirming at each step. But now they can use modern DNA sequencing techniques to determine the plant's entire genetic makeup. With statistical algorithms and powerful computers, genetic maps can be constructed and the altered DNA sequence that is causing the desired trait can be identified. Any unique DNA sequence within or closely associated with the desired trait can now serve as the marker, the red dot, for that trait. With this DNA marker the trait is immediately detectable at any stage in the crossing process without having to wait for the plant to grow. This technique is called marker-assisted breeding. DNA is simply isolated from young plants, analysed for one or several DNA markers and, based on the results, selected for the next round of crossing. Checking the DNA marker is all it takes. Mutation breeding, involving irradiation of seeds or other plant material with gamma or x-rays, has developed thousands of novel crop varieties in hundreds of crop species, increased yields and meant billions of dollars in additional revenue for farmers and producers. Marker-assisted breeding vastly reduces the time needed to transfer desired traits into farmer-preferred varieties of the same crop anywhere in the world. In today's rapidly changing and increasingly erratic climate, this is a major step towards ensuring global food security and retaining the biodiversity of our natural resources.