Dr. B. M. Khadi, Director Central Institute for Cotton Research, Nagpur , Maharashtra

Transcription

1 Success Story of Bt Cotton in India Dr. B. M. Khadi, Director Central Institute for Cotton Research, Nagpur , Maharashtra Introduction Cotton is an important fibre crop of global significance, which is, cultivated in tropical and subtropical regions of more than seventy countries the world over. Cotton is the major cash crop of India and accounts for 65% of the fibre used in the textile industry which has 1,063 spinning mills. Cotton plays a key role in the National economy in terms of both employment generation and foreign exchange earnings. Cotton impacts the lives of an estimated 60 million people in India, including farmers who cultivate the crop, and a legion of workers involved in the cotton industry from processing to trading. By way of exports, foreign exchange earnings of cotton amounts to about 10 billion dollar which is one-third of the total foreign exchange earnings of the country. With economic liberalization and globalization sweeping the world there is a scope for India to play a leading role in the cotton production and export of textiles, yarn and raw cotton. India has the largest acreage (9.13 million ha) under cotton at global level and has the productivity of 520 kg Lint /ha and ranks second in production (4.76 million tonnes) after China during It contributes to 16% of the global cotton produce. Cotton production prior to season it was fluctuating around 2.55 to 2.72 million tonnes (Table 1). Over the last 3 years cotton yield in India increased nearly by 50 per cent. Majority of cotton produced in India is consumed domestically and hence, export of cotton from India is only 0.39 tonnes. If this increasing production trend continues in years to come India can become a major exporter of cotton. Researchers have shown that with the adoption of new technologies on farmer s fields, it is possible to increase the average productivity beyond 600 kg lint per ha to augment additional production of million tonnes to meet the projected cotton demand of 5.95 million tonnes by The consumption of cotton in the country has been rising year after year and there is a boost in cotton consumption subsequent to the abolition of Quota Regime from 1st January The VISION STATEMENT prepared by the Confederation of Indian Textile Industry places the requirement of cotton by the Textile Industry by 2010 at 5.95 million tones. The rising trend in cotton consumption during the last decade would be evident from the Fig.1. The total availability of cotton in the country was 5.64 million tonnes in as compared to 4.63 million tonnes in while the demand has increased from 3.47 million tonnes in to 4.90 million tonnes in

2 Cotton Cultivation in India India is the only country to grow all the four species of cultivated cotton Gossypium arboreum and G.herbaceum (Asian cotton), G. barbadense (Egyptian cotton) and G. hirsutum (American upland cotton) besides hybrid cotton. Gossypium hirsutum represents 90% of the hybrid cotton in India and all the current Bt cotton hybrids are G. hirsutum. Cotton is cultivated in three distinct agro-ecological regions (north, central and south) of the country. Approximately 65% of India s cotton is produced on dry land and 35% on irrigated lands. The northern zone is almost totally irrigated, while the percentage of irrigated area is much lower in the central (23%) and southern zones (40%). The lowest being in the central zone, which has nearly 60% of cotton area of our country. Under the rainfed growing conditions rainfall ranges from <400 to > 900 mm coupled with aberrant precipitation patterns over the years leading to large-scale fluctuations in production. In the irrigated tract canal and well irrigation are resorted to including the use of micro-irrigation system. In cotton, bollworms cause significant yield losses. Three types of bollworms, viz. American bollworm (Helicoverpa armigera), pink bollworm (Pectinophora gossypiella) and spotted bollworms (Earias vitella) attack cotton crop. Moreover, about 10% of insecticides on global basis and 45% in India are used for control of insects in cotton crop alone. Insecticides have adverse effects on (i) natural predators and parasites of bollworms, (ii) beneficial insects, (iii) human health and (iv) micro-organisms such as earthworm, blue green algae, and nitrogen fixing bacteria. Use of insecticides also leads to environmental pollution (soil and water), increase in cost of cultivation and sometimes development of resistance in insects against insecticides. Hence, the need for development of bollworm resistant cotton to control yield losses due to bollworms was felt. Bt Cotton and Adoption in India The development of Bt cotton in India from the transgenic cotton of Monsanto, USA, underwent a stringent regulatory process before it finally reached farmer fields. Mahyco had obtained Coker 312-Bt (Cry1Ac)-cotton seed from Monsanto USA, in Biosafety tests indicated safety to goats, cows, buffaloes, fish and poultry. Feed-safety studies with Bt cottonseed meal were carried out with goats, buffalos, cows, rabbits, birds and fish. The results revealed that the animals fed with Bt-cotton seed meal were comparable to the control animals in various tests and showed no ill-effects. Field trial results showed good boll retention and higher yields. Apart from the increase in yields there was a concomitant reduction in the use of insecticides due to Bt-cotton. Thus it was concluded that Bt-cotton has potential to improve the lives of cotton farmers through the provision of favourable environmental and economic consequences. Bt cotton, which confers resistance to Lepidopteron pests of cotton, was first adopted in India as hybrid in 2002 after stringent assessment for bio-safety and profitability. In India, after extensive testing of Bt cotton hybrids (with Cry1 Ac gene) in All India Coordinated Cotton Improvement Project (AICCIP) and farmers field, Government of India has approved commercial cultivation of Bt cotton hybrid with effect from 2002 crop season. In the first year of its (Bt cotton hybrid) release it occupied 38,038 ha. in The area under Bt cotton hybrids has gradually increased from 38,038 ha in to 0.56 million ha by and showed a steep increase to 1.3 million ha. in , an increase of 160% over 2004 followed by a phenomenal enhancement to

3 million ha. in (Fig.2). Notably, India s Bt cotton area in 2006 (3.8 million hectares) exceeded for the first time, that of China s (3.5 million hectares), the third largest cotton producer in the world. Of the 6.3 million hectares of hybrid cotton in India in 2006, which represents 70% of all the cotton area in India, 60% or 3.8 million hectares was Bt cotton - a remarkably high proportion in a fairly short period of five years. Of the 3.8 million hectares of hybrid Bt cotton grown in India in 2006, 34% was under irrigation and 66% rainfed. Thus within a span of five years nearly 41% of the cotton area in India came under Bt hybrid umbrella. It is envisaged that with availability of more Bt hybrids coupled with reduction in seed cost from 2006 onwards, the area under Bt cotton is likely to show a perceptible increase during as well. Among the major Bt cotton-growing states Maharashtra leads the others with 2.0 million ha. (48% of all Bt cotton in India in 2006) cotton followed by Andhra Pradesh and Gujarat with 0.68 million ha. (22%) and 0.33 million ha. (12%) respectively and Madhya Pradesh with 0.31 million ha. (8%). Among the northern states the area was maximum in Punjab with 0.28 million ha. followed by Harayana 0.04 million ha.. It is estimated that approximately 2.3 million small farmers cultivated on average 1.65 hectares of Bt cotton in Thus, it can be seen that the cultivation of Bt cotton hybrids has picked up momentum in the last two years and it is being cultivated in all the three cotton growing zones of the country (Table 2). 3

4 Table 2: State-wise adoption of Bt cotton in India State 2004 (ha) 2005 (ha) 2006 (ha) Maharashtra 200, , ,0000 Gujarat 130, , ,000 Madhya Pradesh 85, , ,000 Andhra Pradesh 80, , ,000 Karnataka 18,000 30,000 80,000 Tamil Nadu 10,000 25,000 - Northern Zone N/A 60,000 Punjab 281,000 Haryana 42,000 Rajasthan 2,000 Total 500,000 13,00, ,1000 Bt Hybrids Recommended for Commercial Cultivation in India Three hybrids viz. MECH 12, MECH 162 and MECH 184 of Mahyco Monsanto were recommended in 2002 for cultivation in central and southern cotton growing zones. In 2004 one more Bt hybrid i.e. RCH-2 was recommended for commercial cultivation, while in 2005, 16 hybrids were recommended for commercial cultivation. During 2006, 42 hybrids have been recommended for commercial cultivation. All these hybrids were developed by private seed companies utilizing different genes (Table 3). In 2006, a total of four events, of which three were new in 2006, were approved for incorporation in a total of 62 hybrids offered for sale in In 2007, 44 hybrids have been recommended for commercial cultivation in central zone, 18 hybrids in north zone and 39 hybrids in south zone. First event known as Bollgard I (BGI), featuring the Cry1Ac gene was developed by MAHYCO sourced from Monsanto and approved for sale. The second event, Bollgard II (BG II with event MON 15985) also developed by MAHYCO and sourced from Monsanto, featured the stacked genes cry 1Ac and cry 2 Ab, was approved for sale for the first time in a total of seven hybrids for use in the Central and South regions. The third event, known as Event 1 was developed by IIT, Kharagpur, and adopted by JK seeds featuring the cry1 Ac gene, and approved for sale for the first time in a total of four hybrids for use in North, Central and South regions during The fourth and last event, the GFM event was developed by Nath Seeds, sourced from China, featured the fused genes cry 1Ab and cry 1 Ac and approved for sale for the first time in a total of three hybrids, one in each of the three regions of India during Bt cotton hybrids approved for commercial cultivation in North zone 30, North and Central 2, Central 64, Central and South 7 and South zone 59. Table 3: Genes utilized for the development of transgenic cotton hybrids in India Name Private Companies ICAR NBRI Gene utilized cry1ac, cry1ac+2ab, cry1ab+ac fusion (China), cry1ac modified (IIT Khargpur, India), Vip3A+cry1Ab, cry1ac+ cry1 F, cry1c cry1aa3, cry1f, cry1ia5, cry1ab, cry1ac, cry1ec The transgenic hybrids released in the country can be categorized in different ways on the basis of transgene involved. They can be categorized in to two groups viz., (i) Bollgard (single gene) (ii) Bollgard II (double gene) and based on species involved they can again be classified into two distinct types (i) Intra-hirsutum (ii) Inter-specific hybrids (hirsutum x barbadense) (i) Bollgard : The majority of transgenic hybrids belong to this group. 4

5 (ii) Bollgard II: This group includes hybrids viz., MRC 7201, MRC 7301, MRC 7326, MRC 7347,MRC 7351; ACH 11-2; KDCHH 441, MRC 7017 BG II, MRC 7031 BG II, NCS 145 BG II, ACH-33-2 BG II. (iii) Intra-hirsutum Hybrids: This group again includes majority of transgenic hybrids hybrids. (iv) Hirsutum x Barbadens Hybrids: This group includes transgenic hybrids viz., MRC 6918 and RCHB 708, Kashinath. Development of Bt Cotton Varieties Indian Council of Agriculture Research and Department of Biotechnology have entrusted the responsibility of developing transgenic cotton varieties to CICR, Nagpur, NRCPB, New Delhi, NBRI, Lucknow, ICGEB, New Delhi and UAS, Dharwad. The available genes cry1ac, cry1aa3 and cry IF were used through Agrobacterium mediated transfer and cry I A(c) gene was transferred as per the protocol standardized by UAS, Dharwad and CICR, Nagpur in G. hirsutum and G. arboreum cultivars. The RCGM replicated multilocation trials and bio-safety are under way. Development of Bt Kits Central Institute for Cotton Research, Nagpur has developed diagnostic kits viz., Bt Express, Bt Detect, Bt-Zygosity, Bt Quant for the detection of Bt toxin and these kits have been effectively deployed all over the country to verify the purity of Bt seed and ensure the supply of quality Bt hybrids seed to the farming community. Pest Management in Bt Cotton With its intrinsic resistance capability to bollworms damage, Bt cotton can become an ideal component for implementing integrated pest management (IPM) quite effectively. The expression of Cry1 Ac protein is not uniform through out the growing period and usually by days of crop age the expression level comes down considerably making the crop relatively susceptible to bollworms. The problem of sucking pest has increased considerably in most of the Bt hybrids. The adoption of the IPM system with all its biological, cultural and other components will be immensely beneficial for economic, effective and eco-friendly management of insect pests in Bt cotton. Impact of Bt Cotton In India The consistent and perceptible increase in cotton production and productivity during last 3 years is partially attributed to higher rate of adoption of Bt cotton in the country. One clear impact of Bt-cotton on Indian agriculture appears to be the replacement of large tracts of varietal areas of north India, with Bt-hybrids, since the technology is available in India only in the form of hybrids. Bt-cotton seems to have reduced the overall quantity of insecticide substantially, only in some parts of the country, coupled with spectacular yield increases reported from Gujarat, while rest of the states have been showing mixed results despite increase in the area under Bt-cotton. Secondary insect pests such as mirid bugs (Creontides biseratence), were found to increase to damaging numbers in unsprayed cotton fields. The tobacco caterpillar, Spodoptera litura, was also found to stage a come back as an economic pest of Bt-cotton. Data showed that thus far there are no symptoms of resistance to Cry1Ac in any of the bollworm field populations tested. The production trends as depicted in Fig.3 clearly indicate that there has been a significant enhancement in production from onwards as compared to the earlier years (from 3.01 mt in to nearly 4.59 mt in ). Adoption of improved technologies including improved varieties/hybrids as well as Bt hybrids, IPM, IRM, new chemistry 5

6 (including Bt cotton) coupled with favourable weather and low insect pest pressure in major cotton growing tracts has enabled this transformation in production and productivity. During , Punjab and Gujarat states recorded much higher productivity than national average and contributed to a large measure in enhancing productivity and production at the national level. The average national productivity showed a remarkable spurt from nearly 303 kg lint/ha ( ) to 520 kg lint/ha in Amongst the three zones northern and southern-recorded relatively higher productivity compared to the central zone and the enhancement was quite conspicuous in as compared to A trend of continuous improvement is quite clear from onwards (Fig.4). The country was the third largest importer of cotton in the world in In the country was the third largest exporter of cotton in the world. The cotton growers in Gujarat achieved cotton yields of 728 kgs/ha., during which was higher than the world average of 715 kgs/ha. To harvest record crops in succession for three consecutive years is a record in itself in as much as never before the country had ever harvested successive good crops. Coincidental with the steep increased adoption of Bt cotton, the average yield of cotton in India, (which had one of the lowest yields in the world) increased from 303 kg per in to 520 kg per hectare in At a national level, this is a major factor in higher cotton production increasing from 2.69 million tonnes in to 4.76 million tonnes in , which is record for cotton production in India. Large scale cultivation of Bt cotton has resulted in the significant reduction of insecticide use to the tune of 40 to 60% less than the intensity on the corresponding non-transgenic varieties. Several studies have evaluated the economic benefits accrued due to the cultivation of Bt transgenic cotton versus the corresponding non-transgenic cultivar. Apart from causing a reduction in the usage of insecticides all over the world Bt-cotton has significantly contributed to enhanced yields. Hence it has become very popular in all cotton growing countries of the world. The large scale cultivation of Bt cotton is likely to usher in an era of eco-friendly cotton cultivation with reduction in the number of insecticidal applications which in turn will enable better sustenance of parasites and predators in cotton crop creating ideal condition for wide spread of adoption of IPM. The relatively early duration of Bt cotton is likely to bring about reduced water requirement by the crop and in a situation as it prevails in north zone will enable timely sowing of wheat. Bt cotton hybrids as well as varieties alongwith related production and protection technologies are likely to play a pivotal role in realising the targets set for cotton production. 6

7 Table 1 : State-wise Cotton Area, Production and Productivity STATE Cotton % Increase Bt Cotton % Cotton Area Cotton Production Area % area Productivity in Increase in (million ha) (million ton) (kg/ha) Productivity (million ha) under Bt Production Cotton PUNJAB HARYANA RAJASTHAN NORTH ZONE GUJARAT MAHARASHTRA MADHYA PRADESH CENTRAL ZONE ANDHRA PRADESH KARANATAKA TAMIL NADU SOUTH ZONE OTHERS LOOS SUPPLY TOTAL