I have no idea why CaCl2 in maltose would determine pollen viability; typical measures of pollen viability use Alexander's stain (viable pollen is blue, dead pollen is turquoise), of fluorescein diacetate (this one requires a fluorescence microscope). Perhaps the anonymous author was deciding viability based on whether the pollen hydrated in that solution or not, and concluding that non-hydrated pollen was dead. Another thing you might try is a simple pollen germination medium (calcium chloride, boric acid and sucrose), although I don't know what would work with Eragrsotis tef, or if its pollen would germinate in vitro. 

For pollen viability: acetic carmin staining is practical and simple as cited by my colleague. but for pollen fertility and or sterlity, you can use I2- KI staining and Haematoxylin staining: see this reference : http://www.shigen.nig.ac.jp/rice/rgn/vol13/v13p124.html

The I2-KI staining might be the simplest one for pollen viability/sterility.

Gunawardena TA, Fukai S and Blamey FPC. 2003. Low temperature induced spikelet sterility in rice. I. Nitrogen fertilization and sensitive reproductive period. Australian J. Agric. Res. 54: 937-946.

The simplest and cheap ways are: lactophenol cotton blue, acetic orcein or Alexander method. These methods say if cytoplasm is present or not, independently cyctopsm is alive or not.

The most releable and widely used method is to measure if vegetative cell plasmamembrane is intact, damaged or absent: Heslop-Harrison & Heslop Harrison Stain Technology 1970 and modified by Shivanna & Heslop-Harrison Annals of Botany 1981. 

I thank everyone for the comments and suggestions forwarded. I have tried the I2-KI solution at a range of dilution levels (e.g 2%; 5% even 9%) but didn't work for Tef. I also tried TTC which also didn’t work. I will try the other techniques suggested.

acetic carmin staining IS simple  way

I tried lactophenol cotton blue and it worked very well. I prepared the cotton blue lactophenol solution by adding 0.05 g of Aniline blue, 20 g of phenol crystals, 40 mL of glycerol, 20 mL of lactic acid and 20 mL of distilled water. Thank everyone for the suggestions; your comments were very helpful. Thanks!  

A very fast and reliable analysis of pollen viability is provided by impedance flow cytometry. The technology is label-free which means that there is no need for incubation with chemical dyes. The battery powered instrument can be used in the lab or in the field. Results are obtained within about a minute. See www.amphasys.com for more information.

I should give it a try too. Thanks Pablo Bolanos-Villegas.