Comprehensive evaluation of agronomic traits and mineral elements of Auricularia heimuer cultivated on corncob substrates

Auricularia heimuer is the third largest cultivated edible mushroom in the world, which not only possesses a unique taste but also is enriched with nutrients. In order to explore the efficient utilization value of lignocellulose in corncob for mushroom production, this paper was conducted by setting high substitution rate of corncob (70%, 81%, 93%) formulas for cultivation. Principal component analysis (PCA) was used to evaluate the main agronomic traits and mineral elements of the substracts, comprehensively. The results showed that the C/N ratio and lignin content in the substrates were positively correlated with the agronomic traits of Auricularia heimuer. In contrast, cellulose and hemicellulose were negatively correlated with them. The range of the C/N ratio was 50.70%, and biological efficiency (BE) was 50% at 70% corncob substitution, with a remarkable improvement in terms of yield traits (mushroom weight, yield, BE) and quality traits (size, thickness, fresh to dry weight ratio, rehydration ratio, mineral element content). The content of macroelements produced by corncob was better than that produced by sawdust. The higher substitution ratio of corncob, the higher the macroelements of the fruiting body. The microelements (Fe, Se, Mn, Mo, B) of the fruiting body in sawdust were significantly better than that in the corncob substrates. PCA showed that the two principal components represented 94.61% of the 11 agronomic traits and mineral elements composition of the four corncobs under high substitution formulas. When the corncob substitution rate was less than 70%, the fruiting body produced by the formula exhibited comprehensive utilization value in terms of quality and quantity. In this study, corncob as a low-value agricultural waste was environmentally transformed into a new resource that could be used to produce high-value edible fungi, which provides a theoretical basis for accelerating the efficient utilization of substrate and the commercialization of mushrooms at industrial level.