India
August 3, 2024
In a groundbreaking achievement, Punjab Agricultural University (PAU), Ludhiana, has become the first research institute globally to successfully utilize the wild cotton species Gossypium armourianum to incorporate resistance against Cotton Leaf Curl Disease (CLCuD) in American cotton. This significant development was revealed by Dr. Satbir Singh Gosal, Vice-Chancellor of PAU, who emphasized that cultivating CLCuD-resistant American cotton varieties in North India could ensure high and stable cotton production, potentially mirroring the transformative impact of transgenic Bt-cotton.
Dr. Gosal explained that CLCuD is the most severe disease affecting American cotton in the North Indian states of Punjab, Haryana, and Rajasthan, as well as in Pakistan. The disease has also been reported in China.
Quoting the figures from International Cotton Advisory Committee (ICAC), Dr. Ajmer Singh Dhatt, Director of Research, disclosed that the three countries – India, Pakistan, and China – produce nearly half (49%) of the world’s cotton. Of the estimated 24.19 million global cotton farmers, approximately 85% (20.44 million) reside in these three Asian nations. Therefore, managing CLCuD is crucial for the sustainability of cotton production both in Asia and worldwide.
Dr. V.S. Sohu, Head, Department of Plant Breeding and Gnetics, highlighted the economic impact of this whitefly-transmitted virus complex. He cited economic losses of around USD 5 billion in Pakistan from 1992 to 1997 and a 40% reduction in cotton yield in India. Beyond yield loss, CLCuD also adversely affects the quality of cotton fiber, the primary economic product of the crop.
Detailing the symptoms of CLCuD, Dr. Pankaj Rathore, Principal Cotton Breeder and former Director of PAU’s Regional Research Station in Faridkot, informed that it begins with the thickening of small veins on young leaves, leading to a continuous network of small veins. Other symptoms include the upward or downward curling of leaves, and in severe cases, the formation of cup-shaped outgrowths on the lower surface of leaves, resulting in stunted plants with fewer bolls. He stressed that developing CLCuD-tolerant cotton varieties is the only viable option for managing this disease. Although several tolerant varieties have been developed in the past, new viral strains have rendered all existing varieties susceptible, including transgenic Bt-cotton hybrids.
Dr. Dharminder Pathak, Principal Cotton Breeder at PAU Ludhiana, elaborated on the breakdown of resistance, a common issue in crop breeding. He noted that related species and wild relatives of crop plants are rich sources of economically important genes. Consequently, PAU initiated a wide-hybridization program nearly 20 years ago to incorporate genes governing CLCuD resistance from wild cotton species into American cotton. This challenging process, hindered by numerous pre- and post-fertilization barriers, has now borne fruit. PAU has developed elite American cotton breeding lines carrying resistance to CLCuD, with the resistance genes transferred from the wild cotton species Gossypium armourianum.
This pioneering achievement by PAU marks a significant milestone in global cotton research and promises to enhance cotton production stability in North India.
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