Germplasm Activity – Evaluation
Evaluation refers to screening of germplasm in respect of morphological genetical, economic, biochemical, and physiological, pathological, and entomological attributes. Evaluation of germplasm is essential from following angles.
1. To identify gene source for resistance to biotic and abiotic stresses, earliness, dwarfness, productivity, and quality characters.
2. To classify the germplasm into various groups.
3. To get a clear picture about the significance of individual germplasm line.
Evaluation requires a term of specialists from the disciplines of plant breeding, physiology, biochemistry, pathology and entomology. First of all a list of descriptors (Characters) for which evaluation has to be done is prepared. This task is completed by a team of experts from IPGRI, Rome, Italy. The descriptions are ready for various crops. The material is evaluated at several locations to get meaningful results. Moreover, evaluation is done in a phased manner. The variation for polygenic character is assessed by three different methods as given below:
1. By simple measures of dispersion (range, standard deviation, standard error and coefficient of variation)
2. By metroglyph analysis of Anderson (1957) and
3. By D2 statistics of P.C Mahalanobis (1936).
The evaluation of germplasm is down in three different places, viz. 1) In the field, 2) In green house, and 3) In the laboratory, observation on morphological characters, parameters like photosynthetic efficiency and transpiration rate can be recorded under field conditions using portable instruments. The resistance to biotic and abiotic stresses can also be screened under green house conditions. Evaluation for biochemical characters like protein, oil and amino acid contents, and technological character is competed under laboratory conditions. Both visual observation and metric measurements are used for evaluation.