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Abstract
Aim:
Developing high yielding single spore isolates and hybrid strains of paddy
straw mushroom (Volvariella volvacea) with superior nutritional
composition of the fruiting bodies.
Methodology: Two contrasting high yielding strains (DMRO-463 and
DMRO-484) of V. volvacea previously released for higher fruiting body
yield were used for isolation of single spore isolates (SSIs). The slow
growing SSIs were used for developing the hybrid strains by mating on Malt
Extract Agar Medium Petri dishes. Conversely, the fast growing SSIs and the
developed hybrid strains were screened for downward mycelial growth on paddy
straw filled in wide mouth test tubes. Based upon downward mycelial growth,
only eight SSIs and ten hybrid strains with numerically higher downward
mycelial growth compared to two parents' checks were further evaluated for
fruiting body yield on composted cotton ginning mill waste substrate under
indoor conditions.
Results:
In successive yield evaluation trials (one preliminary and three full scale),
hybrid strains VvH-11, VvH-13 and VvH-18 gave fruiting body yield higher than
the two parents. Out of these hybrids, the yield distribution at different
height (selves) in growing room was consistent in hybrid VvH-13 in trial-2,
while rest two hybrids and parents showed significantly lower yield in lowest
self (30 cm above floor level). The fruiting body weight also showed similar
trend. The fruiting bodies from the highest yielding hybrid VvH-11 exhibited
highest level of crude fiber (2.07%) and ash (10.95%) contents, while the
hybrid VvH-13 giving consistent yield across growing room exhibited higher
level of crude fiber (2.00 %), vitamin C (52.35 mg 100 g-1) and
vitamin D (1434.7 ?g 100 g-1). The third hybrid VvH-18 was superior
in crude fiber (1.74%), manganese (22.46 ppm), selenium (0.26 ppm) and
vitamin C (43.13 mg 100 g-1). All three hybrids exhibited lower
fat (1.54 to 1.86 %) content compared to parents (2.54 to 2.59 %).
Interpretation: High yielding hybrid strains can be
developed in paddy straw mushroom (V. volvacea) through mating of slow
growing SSIs, and their screening involving downward mycelial growth on paddy
straw and repetitive grow out trials.
Key words: Downward mycelial
growth, Fruiting body, Single spore isolate, Volvariella volvacea
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