Drought-Tolerance Indices Calculator
Compute SSI, TOL, MP, STI, GMP, YI, YSI and DRI drought-tolerance indices online with a Spearman rank-correlation matrix.
When to use it
Use to rank crop genotypes for drought tolerance from paired well-watered (Y_p) and stressed (Y_s) yield data, the standard input for breeding and agronomy drought trials. Returns the eight most-cited drought indices in one panel.
When NOT to use it
Do not use when only stressed-environment yields are available (the indices need both potential and stressed yields per genotype). Do not over-rely on a single index; the eight indices weight tolerance and productivity differently and a Spearman matrix between them tells you which agree.
What you get
For each genotype: Stress Susceptibility Index (Fischer and Maurer 1978), Tolerance (Hossain et al. 1990), Mean Productivity, Stress Tolerance Index (Fernandez 1992), Geometric Mean Productivity, Yield Index (Gavuzzi et al. 1997), Yield Stability Index (Bouslama and Schapaugh 1984), Drought Resistance Index (Lan 1998). Plus a Spearman rank-correlation matrix among the indices and a STI-ranking bar chart.
Worked example
Four genotypes with paired well-watered (Y_p) and stressed (Y_s) yield in t/ha.
G1: 50, 40 G2: 45, 30 G3: 60, 30 G4: 35, 28
Expected output: G3 has highest GMP and STI (high productivity); G4 has highest YSI (most stable across environments).
Source: StatVeda built-in example, paired with the analyse page sample for toolId 'droughtindices'.
How to interpret the output
STI and GMP rank genotypes by both productivity and tolerance and are the most useful for breeders pursuing yield under stress. SSI and TOL rank by tolerance independently of productivity. YSI ranks by stability across environments. The Spearman matrix shows which indices agree; pick the index whose ranking aligns with your breeding goal.
Common pitfalls
- Picking a single index without checking which agree via the Spearman matrix.
- Confusing Y_p (potential, irrigated) with Y_s (stressed, rainfed); order matters.
- Treating the indices as comparable across crops without standardising.
Try it in StatVeda
The Drought-Tolerance Indices (SSI / TOL / MP / STI / GMP / YI / YSI / DRI) engine runs entirely in the browser. No signup, no install, no data sent to a server. Paste your data, hit Run, copy the output.
Open Drought-Tolerance Indices (SSI / TOL / MP / STI / GMP / YI / YSI / DRI)References
- Fischer, R. A. and Maurer, R. (1978). Drought resistance in spring wheat cultivars. I. Grain yield responses. Australian Journal of Agricultural Research, 29(5), 897 to 912.
- Fernandez, G. C. J. (1992). Effective selection criteria for assessing plant stress tolerance. Proceedings of the International Symposium on Adaptation of Vegetables and Other Food Crops in Temperature and Water Stress, Taiwan, 257 to 270.
- Bouslama, M. and Schapaugh, W. T. (1984). Stress tolerance in soybeans. I. Evaluation of three screening techniques for heat and drought tolerance. Crop Science, 24(5), 933 to 937.