About Bt Cotton:
Some strains of Bacillus thuringiensis produce
protein crystals during a particular phase of their growth.
The crystals contain a toxic insecticidal protein that
kill certain insects such as lepidopterans
(tobacco budworm, armyworm), coleopterans (beetles) and dipterans
(flies, mosquitoes)
The toxin does not kill the Bacillus because the Bt
toxin protein exists as inactive protoxins but once the insect ingests the
inactive toxin, it is converted into an active form of toxin due to the
alkaline pH of the gut which solubilize the crystals.
The activated toxin binds to the surface of midgut
epithelial cells and create pores that cause cell swelling and lysis and cause
death of the insect.
The toxin is coded by a gene named cry.
There are a number of genes acting against the insects
, for example, the proteins encoded by the genes cryIAc and cryIIAb control
the cotton bollworms, that of cryIAb controls corn
borer.
Specific Bt toxin genes were isolated from Bacillus
thuringiensis based on the crop and the targeted pest which is then
incorporated into the several crop plants.
Recently released varieties:
“Indian
Council of Agricultural Research (ICAR) has identified three Bt cotton
varieties — namely PAU Bt 1, F1861 and RS 2013 — for cultivation in states of
Punjab, Haryana and Rajasthan.
“PAU
Bt 1 and F 1861 were developed by PAU, whereas, RS 2013 was developed at
Rajasthan Agricultural University (RAU), Bikaner. While the PAU Bt 1 was completely
developed at Punjab Agricultural University, the F 1861 and RS 2013 varieties
were converted to Bt version by Central Institute for Cotton Research (CICR),
Nagpur. All the three varieties carry ''cry1Ac'' gene imparting resistance
against bollworm complex,”
Current News:
Haryana grant NOC for
field trial of Bt cotton
Haryana
government has issued a noobjection certificate (NOC) to seed major Mahyco to
conduct field trials on BG-2 RRF, a herbicide tolerant and insect resistant
variety of Bt cotton. "India has allowed commercial use of BG-1 and BG-2
GM cotton in the country while, the approval for the BG-2 RRF has been pending
at various stages. The field trials are likely for the North Zone. The
available BG-2 RRF can provide protection against devastating pest attack such
as “American Bollworm”
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