Stability of head weight in cabbage accessions (Brassica oleracea var. capitata L.)
An understanding of the causes of genotype x environment interaction can help in identifying traits and environments for better cultivar evaluation. The fact that head formation depends on other factors besides the cabbage accessions involved, makes it necessary to investigate accessions responses to agroecological growing conditions. Studied in the present paper was the stability of 21 cabbage accessions (10 cultivars and 11 F1-hybrids) with regard to head weight over three growing seasons. Joint analysis of variance revealed highly significant differences among the cabbage accessions, study years and accessions x year interactions. The parameter stability test showed that seven of the accessions (Kopenhaski and Elisa-F1 as early type; Tucana-F1 as summer type; Srpski melez, SG-3014, Ljubljanski and Rodeo-F1 as late type) significantly deviated from the regression line. Four of the seven accessions are cultivars and three F1-hybrids. These accessions had quite different regression coefficients around or above the value of one. Analysis of stability parameters for head weight showed the following accessions to be very stable: Copenhagen market (an early variety), Grenadier-F1 (a summer cabbage) and Ljubljanski (a late variety).
Key words: Stability, variety, cabbage, interaction, growing.