This has been demonstrated after field tests in more than 50 locations that represent major brinjal growing regions in India during 2004 to 2008, Usha Barwale, Chief Technology Officer of leading private sector seed company Mahyco, told a team of visiting journalists.

Andhra Pradesh, Bihar, Karnataka, Maharashtra, Orissa, Tamil Nadu, Uttar Pradesh and West Bengal are the main brinjal growing areas.

She said during multi-location research trials, various parametres were assessed such as damage caused to insects, yield of marketable fruit, insecticide usage and economic benefits.

Mahyco ( Maharashtra Hybrid Seeds Company Limited), which was first company to commercialise hybrid cotton,has developed insect-tolerant Bt brinjal after success of Bt cotton.

She said that a major insect-pest 'fruit and shoot borer ( FSB)' attacks brinjal crop throughout the life-cycle and is estimated to cause yield losses of up to 60-70 per cent even after repeated insecticide sprays.

"The results of the field evaluations indicate that the mean shoot damage was significantly lower in Bt brinjal hybrids (1.51 per cent) as compared to their non-Bt counterpart (7.06 per cent)," she added.

Mahyco, which is sharing its Bt brinjal technology with public sector institutions of India and abroad (US), is also conducting field trials of the crop in Bangladesh and Philippines.

Highlighting the agronomic performance of Bt brinjal, Bharat R Char, lead Biotechnology, Mahyco research, said Bt brinjal hybrid yielded significantly higher marketable yield in all trial models.

"Mean marketable yield for Bt hybrids was 404.91 quintal per hectare as compared to 236.84 quintal per hectare in non-Bt counterpart," he said.

Underlining economics of Bt brinjal, the two said that the Indian Institute of Vegetable Research ( IIVR), Varanasi, estimated good economic benefit values during LSTs (large scale trials) conducted at 21 locations across 10 states during 2007-2008.

Savings in insecticides costs were derived using economic threshold level (ETL) based sprays. ETL were assessed at each picking during the entire crop period.

"The fruit and shoot borer damage crossed ETL 0.94 times in Bt hybrids while it crossed ETL 7.44 and 7.40 times in Bt counterparts," Usha said.