Development of biometric techniques

A number of new biometric techniques to meet the specific needs of the center's research projects have been developed.

An ICARDA scientist consults with ICARDA Biometrician (right)

Germplasm enhancement

Analysis of a series of yield trials with common checks (a general formulation of unbalanced set-up of check genotypes vs trials and test-plus-check genotypes in incomplete blocks).

A new index for measuring stability index in terms of inter-site transferability of crop varieties introduced and applied over six series of multi-locational trials.

Statistical test for crossover type genotype x environment interaction and estimation of crossover point along with its confidence interval.

Estimation of heritability from variety trials conducted in complete or incomplete blocks, and for single or multi-environments.

Estimation and testing of genotypic and phenotypic correlations in plant trails (evaluated in complete or incomplete block design).

Analysis of incomplete diallel experiments in incomplete blocks.

Statistical assessment of screening techniques for heat tolerance in wheat, using errors in variable models.

Estimation of growth reduction dose for polynomial response relationships in mutation studies (generalization for non-linear models).

Estimation of area of chickpea pinnules using non-linear models with errors in variables.

Estimation of physiological parameters when modeling wheat germination in terms of time and temperature.

Estimation of critical period and its confidence interval.

Spatial variability

Spatial variability masks plant responses in field trials. The challenge for the Unit is to develop biometric techniques to improve quality of inferences by incorporating spatial models to enhance the precision in variety trials of barley, wheat, lentil and chickpea, and in enhancing efficiency of variety selection.

Natural resources management

Procedure for analysis of data from long-term rotation trials at the Center.

Estimation of time-trends, to measure the scale of sustainability of farming systems.

Number of years required to detect significant yield trends in continuous and two-course rotation trials.

Time and covariance model selection for various rotation trials.

Crop modeling using data from supplemental irrigation experiments.

Analysis of data from resource management trials for sustainability of production systems in Egypt.

Analysis of data from long-term crop/livestock trial and on-farm trials.

Multi-locational yield trials, such as this one for chickpea, are analyzed to assesss genotype-by-environment interactions, and to help breeders identify high-yielding and stable varieties.