Oryza glaberrima mature more quickly, and may be sown directly on higher ground, eliminating the need to transplant seedlings. Most is rain-watered, and the soil is often not cultivated. African rice has profuse vegetative growth, which smothers weeds. It exhibits better resistance to various rice pests and diseases, such as blast disease, African rice gall midge ("Orseolia oryzivora"), parasitic nematodes ("Heterodera sacchari" and "Meloidogyne" spp.), rice stripe necrosis virus, rice yellow mottle virus, and the parasitic plant "Striga". Most African rices shatter more than Asian rices, possibly because they have not been domesticated for as long. A few varieties of African rice
Helitron (biology) Helitron (biology) Helitrons are one of the three groups of eukaryotic class 2 transposable elements (TEs) so far described. They are the eukaryotic rolling-circle transposable elements which are hypothesized to transpose by a rolling circle replication mechanism via a single-stranded DNA intermediate. They were first discovered in plants ("Arabidopsis thaliana" and "Oryza sativa") and in the nematode "Caenorhabditis elegans", and now they have been identified in a diverse range of species, from protists to mammals. Helitrons make up a substantial fraction of many genomes where non-autonomous elements frequently outnumber the putative autonomous partner. Helitrons seem to have a major role