Marker-assisted selection

In Thailand, marker-assisted selection has been used in breeding programs for tomatoes, to select for plants showing resistance to bacterial wilt as well as nematode, tobacco mosaic virus, fusarium race 2, late blight and powdery mildew. Resistant lines are currently being evaluated in multi-location fields by private companies.

Downy mildew is one of the most destructive diseases found in maize in Thailand. Researchers have been using molecular techniques, such as Simple Sequence Repeat (SSR), to define marker positions that link to the QTLs of the disease, which are then used in marker-assisted selection. Eight novel QTLs for resistance have been found.

Work is ongoing with rice breeding programs focusing on conferring tolerance to submergence and resistance to brown plant hopper for the most important economic rice varieties.

Molecular genetic markers are now being applied in selective breeding programs for commercially important marine species. Species-specific markers found in several marine species are used for identification of correct broodstock and seed species, as well as for quality control of commercial trading of oyster, mud crab and abalone seed. A population-specific RAPD marker found in black tiger shrimp from the Andaman Sea has been used to verify growth and survival performance among different black tiger shrimp stocks in commercial culture ponds.