Summary
Repeatability of mean downy mildew (Sclerospora graminicola (Sacc.) Schroet.) incidence, regression coefficients and deviation mean squares were investigated for 25 pearl millet (Pennisetum typhoides (Burm.) Stapf. & Hubb.) genotypes in 20 environments by correlating arrays of these stability parameters over subsets of the 20 environments arranged according to the year-wise, random, stratified and extreme methods of environmental division. Correlation coefficients between arrays of mean downy mildew incidence from different pairs of subsets ranged from 0.57 to 0.98 and those of deviation mean squares from 0.58 to 0.96 indicating good repeatability of these parameters. Arrays of regression coefficients from different subsets, on the other hand, showed correlation coefficients that ranged from −0.58 to 0.96. Apparently, the regression index of stability was not repeatable for the genotypes and environments studied. Therefore, in order to identify a widely adapted genotype, testing is required to be carried out over a wider range of environments.
Similar content being viewed by others
References
Chahal SS, Virk DS (1984) Multilocation evaluation and selection of stable genotypes for reaction to downy mildew in pearl millet. Crop Protect 3: 95–102
Eberhart SA, Russell WA (1966) Stability parameters for comparing varieties. Crop Sci 6: 36–40
Finlay KW, Wilkinson GN (1963) The analysis of adaptation in a plant breeding programme. Aust J Agric Res 14: 742–754
Jinks JL, Pooni HS (1979) Non-linear genotype X environment interactions arising from response thresholds. 1. Parents, F1's and selections. Heredity 43: 57–70
Mandel J (1961) Non-additivity in two-way analysis of variance. J Am Stat Assoc 56: 878–888
Pethani KV, Kapoor RL, Chandra AS (1980) Gene action and phenotypic stability for incidence of downy mildew disease in pearl millet. Indian J Agric Res 14: 217–223
Perkins JM, Jinks JL (1968) Environmental and genotype X environmental components of variability. 3. Multiple lines and crosses. Heredity 23: 339–356
Sarr A, Sy AA (1981) Strategic d'analyse de la resistance genetique due Mil (Pennisetum typhoides Stapf. et Hubb.) a. Sclerospora graminicola (Sacc.) Schroet. Phytopathol Mediterr 20: 23–32
Shetty HS, Ahmad R (1981) Physiologic specialisation in Sclerospora graminicola. Indian Phytopathol 34: 307–309
Verma MM, Chahal GS, Murty BR (1978) Limitations of conventional regression analysis — a proposed modification. Theor Appl Genet 53: 89–91
Author information
Authors and Affiliations
Additional information
Communicated by G. S. Khush
Rights and permissions
About this article
Cite this article
Virk, D.S., Chahal, S.S. & Pooni, H.S. Repeatability of stability estimators for downy mildew incidence in pearl millet. Theoret. Appl. Genetics 70, 102–106 (1985). https://doi.org/10.1007/BF00264490
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00264490