BT-Cotton Losing its Magnetism among Indian Farmers
Author: Raghuveer Singh
Every varietal improvement always follows boom and bust theory and Bt-cotton not a different one, he also following the same path. Before 2000 a situation comes in Indian farming that our farmers planning to shift from their commercial crop cotton to other crops because of traditional Non Bt verities were very susceptible to bollworms group (Helicoverpa armigera American bolloworm, Pectinophora gossypiella Pink bolloworm, Earias vittella and Earias insulana Spotted bolloworms). Framers not get anything at the end of cropping season, if they not go for control of the bollworms by application of pesticides bollworms make field bare or if farmers go for pest control than repeated spray with costly pesticides, at last keep farmers hand empty on balance sheet. At that time ray of hopes comes through genetic engineered tool that is Bt-cotton and Indian farmers welcome it by open hand. In 2002 at the time of Bt-cotton introduced in India only 0.3% areas under it within 13 years it crossed 95% with 11.6 million hectare area under Bt-cotton out of total 12.2 million hectare under cotton cultivation in country in 2015. But after a short span of boom in cotton cultivation (almost one decade) in country, again Indian farmers facing problem and in trouble situation due to biotic and abiotic pressure exerted by sucking pest (mainly white fly) and parawilt (mainly water logging or saturated field) respectively.
In 2015, one of the worst years in Indian history that farmer faced heavy loss due to the attack of white fly in Punjab and Haryana of north Indian states. Before Bt-cotton introduced in India white fly along with other sucking pest (jassid and aphid) considered as the minor pest of cotton but after introduction of Bt-cotton sucking pest converted from minor to major pest and white fly is an epitome example of it. No doubt that we controlled the borers but also opens the door for new pest. If farmers get successful to save their crop from white fly at initial stage but they trapped by parawilt at later reproductive stage.
Parawilt also called as sudden wilt and new wilt, it is typical type of wilt in which plant suddenly wilted within few hours. Sporadic distribution and untimely occurrence make it difficult to understand even for researchers so it’s impossible for farmers for control at field level on their end. Earlier our researchers thinking that parawilt is a pathological disorder, but later on when they found that none of the pathological control measures works on it. Then they reexamine it and concluded that it is a physiological disorder. Now it is well established fact that it is physiological disorders. Which have multiple cause like as lack of water/flooding, nutrient deficiency/surplus application of fertilizers, too much sun/not enough sun. Normal wilting caused by lack of water or by pathogen attack show gradual pattern and it can be controlled. On other side papawilt very complex (multiple factor with both side limitation, too less/too much) and impossible to control (very short period and less recovery reported once it occur). In cotton, it was first reported during rainy season at Adilabad Districts of Andhra Pradesh in 1978 in intra hirsutum hybrid JKHY-1. No doubt that parawilt not obligate physiological disorders of the Bt-cotton it also occur in Non Bt but due the more pod retained in Bt-cotton at the time of reproductive phase make it more vulnerable than the traditional Non Bt verities. In a lay man word we can say that in Bt-cotton more metabolic active and more pressure exerted by developing pod at reproductive phase. So plants are unable to balance between the higher production level and unfavorable environmental condition and ultimately plant come under stress and show sudden wilting. It is necessary evil of higher production level that, plant can’t handle both higher productivity and physiological discomfort side by side. In parawilting chances of recovery very less only little bit recovery reported at early stage of plant but at later on boll development stage it is impossible task for plant to recover from it. Most common parawilt in cotton field reported is sudden rain fall (after long dry spell), followed by the bright sunshine hour create anaerobic condition in the root zone show transpiration get stopped and plant unable to fulfill the transpiration pull demand of bright sun hour. Sudden wilting due to saturated field (over watering/heavy rain) more faced by clay textured or poor drained soil than the sandy soil. So our researchers can suggest to our farmers different agronomic package and practices for Bt-cotton cultivation under clay and sandy soil. There should be a provision for drainage of excess water in clay and poorly drained soil area, if farmers planning to go for Bt-cotton cultivation.
One thing is clear that Bt-cotton have potential of higher productivity but every coin have two side so it is necessary that we (researchers) understand new physiological demand and new emerging pattern of pest for harvest the advantage of genetic engineering ambled cotton.
References:
1. Hebbar KB, Mayee CD (2011) Parawilt/sudden wilt of cotton - a perspective on the cause and its management under field condition, Current Science 100 (11) 1654-62.
2. Perumal NK, Hebbar KB, Rao MRK, Singh P (2006) Physiological disorders in cotton CICR Technical Bulletin No: 28 http://www.cicr.org.in/pdf/physiological_disorder.pdf
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About Author / Additional Info:
I am working as a scientist at ICAR-IIFSR, Modipuram, Meerut, Uttar Pradesh, India.