Oyster mushroom variety named ‘WUR SF3’

Botanical classification:

Varietal denomination: ‘WUR SF3’.

The present application claims priority to European Community Plant Variety Rights Application No. 2024/1221, filed May 30, 2024, which is herein incorporated by reference.

The present invention comprises a new and distinct cultivar of mushroom of the speciesknown by the varietal name ‘WUR SF3’. The new variety was discovered in Wageningen, The Netherlands. The purpose of the breeding program was to develop a sporeless strain of oyster mushroom. The new variety has been trial and field tested and has been found to retain its distinctive characteristics and remain true to type through successive propagations.

The following detailed description sets forth the breeding procedures and the characteristics of the new cultivar. As shown in Schematic 1, in breeding the new variety, parental lines were isolated from P80 (female parent; unpatented) and ATCC 58937 (male parent; unpatented). Both the male and female parent were protoplasted to obtain the constituent monokaryotic parental lines. In parallel breeding lines, the monokaryons of the male parent were used to introduce the sporeless trait into the parental monokaryons of the female parent. After this in both parallel breeding lines a backcross strategy was used to largely restore the genotype of both parental lines of the female parent, without losing the sporeless trait. The products (single spore isolates) of the parallel breeding lines were combined by mating to obtain the final product.

The new variety differs from the parents in that it does not produce basidiospores (unlike P80) and produces large and firm mushrooms (unlike ATCC 58937). The variety is similar to the female parent in that it produces large and firm sporulating mushrooms and is similar to the male parent in that it does not produce basidiospores. ‘WUR SF3’ slightly differs from another variety of sporeless Oyster mushroom, ‘SPOPPO’ (patented, U.S. Plant Pat. No. 18,037) in color of the mushroom cap. Next to this, required climate conditions to induce pinning differ, and the time needed between inoculation and production of the first flush is longer for the new variety. Characteristics that distinguish ‘WUR SF3’ from other varieties known to the breeder include:

The color standard used in the present application is the Lab* method (also designated as CIE.LAB or CIE-Lab*) defined by “Commission International de l'Eclaire” in 1976. The location where measurements were made was Wageningen, The Netherlands. Light conditions where measurements were made were by artificial light provided by a Minolta Chroma Meter type CR-200.

The variety was cultivated on a commercially available pasteurized wheat straw substrate. After pasteurization the substrate was inoculated with 30 liter of spawn per 1000 kg Fresh Weight substrate and pressed in 20 kg blocks wrapped in microperforated plastic foil. A total of 20 large perforations (1 cm diameter) were made per substrate block to provide room for the future development of primordia and subsequently, fruiting bodies. Spawn-run was performed at a substrate temperature aimed at 28° C. and relative humidity of 75%. When the substrate temperature exceeded 32° C., the air temperature in the growing room was lowered. After 18 days of spawn-run the growing room was vented in 2½ days to an air temperature of 14° C., a relative humidity of 93% and a COlevel of 850 ppm to induce primordia. At the appearance of primordia, the relative humidity was lowered to 90-92%. During maturation of the fruiting bodies, the relative humidity was lowered further to 88%. Mature mushrooms were harvested just before the rim of the mushroom starts to fold upwards. Immature mushrooms are usually not harvested commercially. Mushrooms of 2-3 cm cap diameter were used as representative for immature mushrooms.