<div>Background: Colchicine acts as a polyploidy inducer but at high concentrations, it causes high cell mortality. To improve the efficiency of colchicine polyploidization in cassava, leaf lobes colchicine-sensitivity tests were carried out and LD50 determined at 0.00, 0.05, 0.10, 0.20 and 0.25g/l colchicine concentrations in the varieties Ankrah, Dagati, Tomfa and Tuaka.&nbsp; 
 
Methods: Colchicine treated leaf lobes were regenerated into callus on either 8 mg/l 2, 4-D or Picloram. The calli were subsequently regenerated into somatic embryos by NAA. LD50 of 0.09, 0.11, 0.13 and 0.09 mg/L colchicine concentration were determined for Ankrah, Dagati, Tomfa and Tuaka respectively in 2, 4-D.&nbsp; Similarly, LD50 of 0.12, 0.10, 0.14 and 0.10 mg/L were respectively obtained in Picloram.&nbsp; 
 
Result: In 2, 4-D, Ankrah and Tuaka were more sensitive to colchicine than Dagati and Tomfa whereas in picloram, Dagati and Tuaka showed more sensitivity. Callus proliferation differed significantly among varieties and influenced by the concentration of colchicine.&nbsp;</div>

Colchicine-sensitivity Test in Cassava Leaf Lobes and its Effect on Callus and Somatic Embryo Formation

<div>Background: This experiment was done to analyze the colchiploids obtained in two bajra napier hybrid genotypes named CO6 and TNCN 1534. Stomatal size is considered as one of the main parameters in analysing the variants developed by colchicine application.&nbsp; 
 
Methods: Two methods were adopted for inducing polyploidy BN hybrids. In case of whole immersion method, budded setts were completely immersed in concentrations of 0.05%, 0.10%, 0.15%, 0.20% and 0.25% for 3 and 6 hours duration. In case of the cotton swab method, the nodded setts were covered with a thin layer of cotton and same five concentrations were given continuously for a period of over two days. After transplanting them in the field for 30 days, evaluation of stomatal length and width was done.&nbsp; 
 
Result: The stomatal measurements changed with various range of concentrations and the method of application. In the case of whole immersion method, 0.20% and 0.25% concentration for 3 and 6 hours produced variants having largest width and length of stomata and also covered the largest range for mean values. In cotton swab treatment, highest range for stomatal measurements were seen at 0.20% and 0.25% concentrations. The whole immersion method was able to generate a wide range for stomatal length and width as compared to cotton swab method. Hence, it can be deciphered that whole immersion method was more effective than cotton swab method in this study. The highest concentration of 0.25% was the most effective in inducing changes in the treated plants in both the methods. Through this, we were able to identify some putative colchiploids in the study. These screened polyploids were forwarded for further analysis which were then used to identify genotypes having desirable forage and quality parameters.</div>

Colchicine-sensitivity Test in Cassava Leaf Lobes and its Effect on Callus and Somatic Embryo Formation

Stomatal Studies on Colchicine Treated Bajra Napier Hybrids (Pennisetum glaucum x P. purpureum)