( ( Polyploidy Induction in African Marigold (Tagetes erecta L.) by Colchicines Prabhat Kumar Singh*, Diana Sagolsem, Chandrashekar Chaterjee, Argadeep Ganguly and R. Sadhukhan Department of Genetics and Plant Breeding, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia , West Bengal - 741 252 (India) *Corresponding author e- mail id – prabhat4u.gen@gmail.com ) ) Introduction African marigold (Tagetes erecta L.) is seasonal flowering plant, belongs to the family Asteraceae and is native to the South and Central Americas, especially Mexico. It has great importance for landscaping and can be used as bedding and potted plant. Marigold in general tends to be planted as annuals, although the perennial varieties are gaining popularity Its flower petals serve as a major source of Carotenoids and leaves are effective to control root-knot nematodes. so it is being grown for flowers in addition to its medicinal value like other ornamental plants. Ploidy manipulation has been found a valuable tool in the genetic improvement of many plants. Polyploidization can help to increase the size of flowers, intensify the flower color and modify plant shape. Objective The present experiment was therefore laid out to study the Polyploidy inductions through application of colchicines in a commercially grown African marigold. Materials and Methods The present experiment included one marigold genotype (Bidhan Marigold 1). Absorption of colchicines was done through buds at two leaf stage in the field. The small apical bud was covered by the absorbent cotton and tagged. Colchicine solution (5 ppm) was dropped on the bud covered with absorbent cotton.. This was done to a number of plants. Few plants were also kept untreated. The procedure continued for 4 to 6 hours in the field in shade condition. Then after 7 days all the plants were transplanted to the main experimental field of Mandori farm of B.C.K.V. Stomata were extracted from the ventral surface of leaves by peeling method and then studied under the microscope (10X × 10X field) after placing in 5% glycerine to check evaporation of water Table 1: Stomatal guard cell Length, Breadth and Area CONTROL TREATMENT Observation LENGTH (µm) BREADTH (µm) AREA (µm2) No. 1 24.09 19.13 460.84 26.95 21.41 576.86 No. 2 27.14 18.03 489.33 30.62 24.33 744.71 No. 3 23.77 15.06 357.98 28.15 22.70 639.01 No. 4 23.15 15.89 367.85 27.91 20.12 561.41 No. 5 20.88 16.5 344.52 31.47 18.42 579.68 No. 6 21.09 16.98 358.10 22.95 19.62 450.28 MEAN 23.353 16.93 395.32 28.07 591.99 Table 2: Number of Stomata under 10X × 10X field Result and Discussion While computing the length and breadth to estimate the total dimension, the stomatal dimension of the colchicines treated plants appeared to be greater (mean values) than the untreated control (Table 1.). The observed lower frequency of stomata studied from the leaves of 5 ppm. colchicines treated plants than the leaves of untreated control (Table 2.) CONTROL TREATMENT. OBS. 1 1524 1028 OBS. 2 1428 940 OBS. 3 1604 1140 MEAN 1518.67 1036 Conclusion: The colchiploid treated marigold plants scored on the basis of stomatal frequency and dimension of guard and subsidiary cells (Fig.) requires to be confirmed from further cytological studies. Fig.- showing stomata frequency and stomata measurement of colchicines treated and untreated plants Fig.- Colchicine treared plant National symposium on sustainable agriculture for food and nutritional security in east and north east india : prospect & future at Institute of Jute Technology, Calcutta University , March 01, 2014