MORPHOLOGICAL AND MOLECULAR IDENTIFICATION OF MYCOFLORA ASSOCIATED WITH SELECTED SPAWN SUBSTRATES AND ITS EFFECT ON YIELD OF OYSTER MUSHROOM (Pleurotus florida)

Abstract

An experiment was conducted to identify and characterize contaminants associated with the substrates of oyster mushrooms (Pleurotus florida) based on morphological and molecular characteristics, to assess the degree of contamination of various oyster mushroom substrates and to determine the effect of mycoflora on the growth and yield-contributing traits of Pleurotus florida. Five different types of mushroom substrates, including rice straw, sugarcane bagasse, waste paper, grass (Cynodon dactylon) and banana leaves were used for this purpose. By morphological and molecular analysis, three fungi were isolated and identified from mushroom substrates. These were Exophiala spinifera, Trichoderma asperellum, and Rhizopus sp. Among these fungal isolates, the DNA sequence of Trichoderma asperellum and Exophiala spinifera were detected by Basic Local Alignment Search Tool (BLAST) with the help of NCBI. DNA sequence of Exophiala spinifera and Trichoderma asperellum were matched by 99.83% (ITS1) and 100% (ITS4)as well as 65.60% (ITS1) and 99.50% ( ITS4) with the nucleotide sequence of NCBI gene bank, respectively. Among the five mushroom substrates, waste paper showed the highest mycelium growth rate (0.48 cm), while banana leaves showed the lowest growth rate (0.41 cm). For mycelium running completion, sugarcane bagasse required the longest period of time (15.8 days), whereas waste paper required the shortest period of time (12.3 days). The maximum number of primordia (37.9), effective fruiting bodies (17.5), the highest biological yield (144.2 g), economical yield (113.3g) and biological efficiency (24.84%) per spawn packet were recorded from waste paper, while the minimum number of primordia (30.9), effective fruiting bodies (12), biological yield (119.7 g), economical yield (86.2 g) and biological efficiency (23.94%) were recorded in banana leaves. The maximum pileus diameter (5.03 cm) and stipe length (2.84 cm) were recorded from grass (Cynodon dactylon) whereas the minimum pileus diameter (3.61 cm) and stipe length (2.26 cm) were found in banana leaves. The maximum contamination severity was recorded in banana leaves (6.8%) whereas waste paper had the minimum level of contamination (0.4%). Among the selected substrates, waste paper showed the best performance in case of growth rate, mycelium running completion, yield and yield contributing characters.