SAMP                   SAMP 1      SAMP 2  

Calculating the Ellis and Roberts' Seed
Viability Equation in EXCEL


Viability Equation:    

n =  Ki -  P · ( 1/10Ke - CwlogM - ChT - CqT2 )

n = final % viability after p days storage
Ki = initial viability at p = 0 days
P   = storage days
M  = moisture content of the seed (hermetically sealed)
T   = temperature (not fluctuated)
Ke, Cw, Ch, Cq = viability constants, species specified


some references:

Dickie, J.B., R.H. Ellis, H.L. Kraak, K. Ryder and P.B. Tompsett 1990 Temperature and seed storate longevity. Ann. Bot., 65:197-204.

Ellis, R.H., T.D. Hong and M.T. Jackson (1993) Seed production environment, time of harvest, and the potential longevity of seeds of three cultivars of rice (Oryza sativa L.). Annals of Botany, 72:583-590.

Ellis, R.H., T.D. Hong and E.H. Roberts 1992 The low-moisture-content limit to the negative logarithmic relation between and longevity and moisture content in the three subspecies of rice. Ann. Bot., 69:53-58.

Ellis, R.H., T.D. Hong and E.H. Roberts 1995 Survival and vigour of lettuce (Lactuca sativa L.) and sunflower (Helianthus annus L.) seeds stored at low and very-low misture contents. Ann. Bot., 76: 521-534.

Roberts, E.H. and R.H. Ellis 1989 Water and seed survival. Ann. Bot., 63:39-52.


press: SAMP 1  or    SAMP 2   to open the file, if  using IE 4.0 or higher, or stored in hard disk and open as an excel file.


  1. stored the seed sample bags at constant environment.
  2. at due time, withdraw one bag and test % germination.
  3. get at least three tests.
  4. input A4 and B4 for the fist test, A5 and B5 for the second......
  5. viability equation instantly presented: i.e. Y = 2.8799 -0.092168132 X
  6. to predict viability after x days storage, just key in E14 or below
  7. or consult the figure in other worksheet: probit / percent

SAMP 2: to predict storage days or storage condition (temperature, seed moisture content) needed in some species..