A PARSIMONIOUS STATISTICAL DESIGN AND BREEDING PROCEDURE FOR EVALUATING AND SELECTING DESIRABLE CHARACTERISTICS OVER ENVIRONMENTS

The concept of stability as described in the literature does not meet all of the desirable criteria required by growers of cultivars. Variou s types of possible responses are discussed, and these are divided int o those desirable from a grower's viewpoint and those not. Measures of stability appearing in the literature are based on variances, linear regression slopes, and/or deviations from regression. The most desirab le response type would be denoted as unstable by current concepts of s tability. It is shown how to simulate environments that exceed the ran ges found in practice. A statistical design is described which is the height of parsimony and has the advantage that the conditions varied a re known. The experimental results can then be interpreted in light of the known conditions. The design is optimally cost effective in terms of funds, material, and personnel. A breeding procedure is presented for such characteristics as desired response, stability under current definitions, tolerance (to pests, cold, drought, etc.), protein, quali ty, fiber, etc.