الفهرس 
ABSTRACT
contamination and disinfection of the explantsOnly 14 pages are availabe for public view
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Abstract
The present investigation on in vitro propagation of Taro was conducted during 2009 and 2010 in the tissue culture laboratory, Department Vegetable, Faculty of Agriculture, Assiut University, Assiut, Egypt. Dairout ecotype of taro (Colocasia esculenta var. antiquorom) was used. This cultivar was obtained from taro field of Dairout city (Colocasia esculenta var. antiquorom). Dairout cultivar is known to produces large corm and pink roots. Disinfection and micropropagation of the taro cultivar was investigated as influenced by disinfectants, sucrose concentration, plant growth regulator supplements.
Contamination remains a continuing threat to in vitro taro germplasm conservation, but techniques for reducing contamination are available. Laboratories must change their laboratory operations to avoid or eliminate most of the contaminants. Taro corms of Dirout cultivar were brought to the Tissue Cutler Lab. of the Department of Vegetable, Faculty of Agriculture, Assiut University. Explants consisting of buds, embedded deep in the corm tissue encircled with leaf primordial, and basal part of the petioles (5-10 mm diameter, 20-40 mm length) were used to establish the tissue culture experiments. Taro explants were then immersed in ethanol alcohol (70%) for 5 minutes and then by washing them three times with sterilized distilled water followed by treating them with the commercial bleach Clorox (sodium hypochlorite 5%) at 5%, 10%, 15%, 20%, 50% of its original concentration followed by three rinses in pure sterile water for 5, 10, 15, 20 min. Sterilizing the taro explants with 15% of the commercial Clorox for the period of 20 min gave very good results in overcoming contamination and gave the highest rate of proliferation and growth of the taro buds. Using the Rose Bengal dye helped to eliminate contamination but limited the explants proliferation.
The effect of various sucrose concentrations (20, 40, 60, 80, and 100 g) that were added to Ms or B5 media on the growth of the taro corm was studied. It was found that using 40 g of sucrose enhanced all the studied traits such as the corm formation, the stem height, the whole plant height and the corm weight.
The effect of various two growth regulators concentrations that were added to Ms or B5 media on the growth of the taro corm was studied. All the possible combination of various concentrations of IBA (0, 1 and 2 mg/L) and GA3 (0, 5 and 10 mg/L) were used in this study. It was found that using 5 mg/L GA3 when was added to the medium in addition to 2 mg/L IBA enhanced all the studied traits.
It is recommended that taro explants may be successfully sterilized by placing them in ethanol alcohol (70%) for 5 minutes and then by washing them three times with sterilized distilled water. Further, the buds then should be placed in the commercial bleach Clorox (15%) for 20 minutes and then washed three times with sterilized distilled water three times in a row to get rid of the effects of Clorox before being cultured in vitro. Finally, using MS or B5 media supplemented by 40 g of sucrose in addition to 5 mg/L GA3 and 2 mg/L IBA can enhance the taro corm formation, size and height.