TABLE 2.

Selected parental S. cerevisiae strains for the generation of novel hybrids^a

Strain name	Parent type	Thermotoleranceb	Isoamyl acetate production (AU)c	Spore viability (%)	Mating type segregantsd
H28	Robust	+++	0.5	75	a, α, or a/α
Y115	Robust	+++	0.7	100	a or α
Y181	Aromatic	+	3.6	50	a/α
Y184	Aromatic	++	4.0	94	a/α
Y354	Aromatic	++	3.6	31	a or α
Y397	Aromatic	+	2.7	44	a, α, or a/α
Y927	Robust	+++	1.6	100	a/α

^aStrains Y115, Y927, and H28 were selected based on their thermotolerance and excellent performance during inoculated cocoa pulp fermentations. Y181, Y184, Y354, and Y397 were selected based on their high fruity aroma production.

^b+, less than that of the reference strain; ++, equal to that of the reference; +++, more than that of the reference. The reference for thermotolerance was S. cerevisiae W303 (32).

^cIsoamyl acetate production was measured in nutrient-rich growth medium (10% YPD) and compared to the average production of 236 S. cerevisiae strains (23). AU, arbitrary units.

^dMating types were determined using mating-type PCR.