Having grown Bt hybrids incorporating Monsanto’s proprietary Bollgard (BG-I/BG-II) technology for the last 13 years, Indian cotton farmers can look forward to sowing much cheaper straight varieties using high-density planting (HDP) and three new “genuinely indigenous” genetic modification (GM) events.
The Central Institute of Cotton Research (CICR) in Nagpur has signed a memorandum of understanding with Delhi University, whose scientists, led by its former vice chancellor Deepak Pental, have developed a cotton transgenic event, ‘Tg2E-13’, based on the Cry1Ac gene isolated from the soil bacterium Bacillus thuringiensis or Bt.
This new event, showing high expression levels of the Cry1Ac protein throughout the plant’s lifecycle as compared with all the current events in the field, will enable planting of cotton varieties with significant resistance to the American bollworm pest.
“We are about to sign two more MOUs. One is with the National Botanical Research Institute in Lucknow (whose scientists led by Rakesh Tuli have used a synthetic Cry1EC gene for conferring resistance to the leaf-eating spodoptera litura or tobacco caterpillar) and the other with Tamil Nadu Agricultural University (where a team under V Udayasuriyan have developed an event expressing the Cry2AX1 gene for toxicity against bollworms),” said CICR director, Keshav Raj Kranthi.
CICR plans to stack all the three GM events into its cotton varieties, which can compete with Monsanto’s Bollgard. The three events will express four toxins, as Cry1EC is a synthetic hybrid between Cry1E and Cry1C genes. Monsanto’s BG-II event contains only two Bt genes, Cry1AC and Cry2Ab. The US life sciences major is also preparing to launch a new BG-III event incorporating an additional Vip3A Bt gene to confer further effective resistance against insect pests. “We hope to make available our four-gene stacked GM event varieties to farmers around the same time Bollgard-III is approved for commercial cultivation,” Kranthi told The Indian Express.
This is not the first attempt at developing a desi Bt cotton event. Scientists at the University of Agricultural Sciences in Dharwad, Karnataka, had introduced the Cry1Ac gene into a popular variety — Bikaneri Narma. But the field performance and yields of the released Bt variety not only failed to match expectations, the seed samples were also found to have contained Monsanto’s original MON-531 event.
CICR scientists are, nevertheless, excited about the new “genuinely indigenous” transgenic events. What they are primarily aiming is to incorporate these into straight varieties, as opposed to hybrids.
“Varieties have distinct advantages over hybrids. They are sturdier, making them more suitable for dry-land cultivation. More importantly, they don’t have to be bought each time, since farmers can use the seeds from previously harvested crops for re-planting. It cuts down input expenses, as varietal seeds cost Rs 50 per kg, as against the Rs 930 that they are now paying for 450 grams of BG-II hybrid seeds,” Kranthi noted. Moreover, CICR wants to promote the cultivation of the new GM event varieties using HPD systems. This involves sowing the cotton in closer-spaced rows, with 1,10,000-2,20,000 plants per hectare, as against the currently followed planting density levels of 11,000-15,000. Such plantings are obviously more feasible with varieties than costlier hybrid seeds.
“Our average yields, which are now around 16 quintal of kapas (un-ginned raw cotton), can easily go up to 30 quintals under the proposed HDP regimen,” claimed Kranthi. Unlike the earlier varieties that were bushy like the hybrids, the newly developed varieties — including CICR-CSH 3178, DSC 99, ADB 39, ARBH 64, G Cot 16, F2383, JK 4, BS 279 and NDLS 1938 — are compact-statured and can yield more by being amenable to HDP. Besides, they are comparatively early-maturing and shorter-duration varieties that enter boll-formation stage by September when the plant is most susceptible to bollworm attacks. “So, even without Bt, they can give much higher yields under HDP systems. And with Bt, they would be clear winners,” Kranthi added.
According to him, India was an exception among top cotton-producing countries in planting 95 per cent of its area under Bt hybrids. All others — from China and Brazil to the US and Australia — plant only varieties based on HDP. “Bt cotton has, no doubt, provided protection against bollworm. But we need to ponder why our yields hit a peak of 560 kg (of lint) per hectare in 2007 and haven’t increased since then,” he pointed out.
The way ahead, Kranthi said, was to go move from Bt hybrids to varieties and cultivating them under HDP. He, however, admitted that it will take 3-4 years for the new HDP-amenable Bt varieties to go through testing protocols and field trials, before they can reach the farmer. And whether the green lobby will allow it is, of course, a moot question.