Evaluation of Gray Leaf Spot Tolerant Genotypes from CIMMYT in the Highland Maize Production Eco-systems of Bhutan  

作　　者：Tirtha Bdr. Katwal Dorji Wangchuk Lhap Dorji Namgay Wangdi Rinzin Choney 

机构地区：[1]Renewable Natural Resources Research and Development Centre, Wengkhar, Mongar, Bhutan [2]Department of Agriculture, Ministry of Agriculture and Forests, Thimphu, Bhutan

出　　处：《Journal of Life Sciences》2013年第5期443-452,共10页生命科学（英文版）

摘　　要：Bhutan is a small landlocked country located in the eastern Himalayas. Over 69% of the population is engaged in agriculture. Rice, maize, wheat, barley, buckwheat and millets are the major cereal crops cultivated. Rice is the most preferred food crop of the Bhutanese. Maize is a primary food crop after rice and it ranks first among food crops in production. The cultivation ranges from less than 300 m asl （metres above sea level） nearly up to 2,800 m asl. In 2007, a new, extremely serious problem of GLS （gray leaf spot） in maize that was previously never reported in Bhutan was confirmed. This disease spread rapidly in the highland maize growing areas causing production losses of over 50% to 70%. All the maize varieties cultivated in the country were found to be highly susceptible to the disease. In order to contain this devastating disease, the national maize program drew short and long term strategies with the help of a CIMMYT Expert. As an immediate short term action to contain GLS, systemic fungicide Tilt 25 EC （active ingredient propiconazole） was supplied free of cost to the farmers. A longer term strategy pursued was the introduction, e＇valuation and selection of GLS tolerant genotypes for the highland ecosystem. Over 100 GLS tolerant genotypes vcere introduced from CIMMYT Colombia, Mexico, Zimbabwe and Nepal. These materials were initially evaluated in a disease hotspot sites and then further tested in multi-location trials in GLS affected areas across the country. Farmers were engaged for Participatory Variety Selection by organizing farmer＇s field days at the trial sites. Finally, in 2011 considering the need of GLS tolerant varieties for farmers, two GLS tolerant genotypes ICAV305 and S03TLYQAB05 were provisionally released. In the 2011 season, these two provisionally released genotypes were put under large scale demonstration in the GLS affected areas in nine districts across the country. In 2012, the two genotypes were formally released by the Technology Release Committee of the Ministr

关 键 词：Gray leaf spot HOTSPOT yield loss participatory variety selection community based seed production and seedreplacement. 

分 类 号：Q[生物学]