Table 3.

Percentages of killer, sensitive, and resistant Saccharomyces sensu stricto yeasts in the must fermentations made at different periods of the vintage seasons^a

Yeast phenotype	% at vintage season periodb:			Pc
	Beginning	Middle	End
Killer (K2 and Klus)	12 ± 5.5	21 ± 6	55 ± 8	0.001
Nonkiller resistant to K2	39 ± 13	60 ± 6.9	32 ± 7	0.032
Nonkiller sensitive to K2	49 ± 11	19 ± 5.7	13 ± 4.2	0.010

^aKruskal-Wallis nonparametric test to study the effect of the harvest date on the proportions of killer and sensitive yeasts.

^bThe data are the mean values and standard errors of 13, 17, and 12 independent experiments done at the beginning, middle, and end of the vintage season, respectively. The nonkiller yeasts resistant or sensitive to Klus toxin were not considered separately in this analysis because of the difficulty in achieving reliable results due to the weak killer phenotype of Klus yeasts and because of their low frequency in the spontaneous fermentations.

^cP values obtained by the Kruskal-Wallis nonparametric test to analyze the changes in the proportions of killer yeasts in the must fermentations over the course of the vintage season.