Study On The Excellent Strain Selection And Spawn-Bag Formula Cultivation Of Morchella

As one of the most famous edible mushroom,morel(Morchella spp.)is widely loved by consumers for its delicious taste and unique fragrance.At present,Morchella importuna and M.sextelata have been artificially cultivated in the field in China.The stabilities of varieties and cultivation techniques are important for growing industry.With the increase of the growing scale,the cultivation yield,production cost,nutrient-bags contamination,and continuous cropping obstacles are seriously restricting the sustainable development of morel growing.The breeding is the first and most important step for agricultural industry,and the goal of variety selection is to obtain the varieties(strains)with good and stable agronomic characters.The breeding of excellent morel strains and the optimization of spawn-bagcultivation methods were studied in this paper.The specific research contents and results are as follows:1.Obtaining single-ascospore heterokaryotic isolations.Three ascocarps JNLM1,JNLM6 and JNLM7 of M.sextelata,and three ascocarps 6611,ZQW and Y1Y3 of M.importuna were used to isolate monospore strains by using spore dilution-spreading method or capillary-isolation method.Fifty-three,58,60,46,33 and 125 isolations were obtained from different ascocarps respectively.The mating types of all strains were detected by PCR.Ninety-seven single-ascospore heterokaryotic strains with both MAT1-1 and MAT1-2 mating type genes were screened out,and 47 isolations numbered 01～47were M.importuna and 50 isolations numbered 48～97 were M.sextelata.2.The relationship between the culture characteristics and the yield of morel strains.The mycelial growth rate,sclerotia formation,sclerotia distribution and mycelium growth from medium side to medium-free one on dichotomous petri dish of 97single-spore heterokaryotic strains were determined.The results showed that there were great differences in average growth rate and sclerotia formation in 97 strains.The sclerotia distribution of M.importuna strains could be divided into three types: concentrated at the edge of the petri dish,concentrated near the inoculation block and dispersed in the whole media.The sclerotia of M.sextelata strains mainly produced in the edge of petri dish.The mycelia of 47 M.importuna strains could grow to the side without culture medium,while50 strains of M.sextelata could not.No any cultural characteristics were found for the strains with higher yield.3.The spawn-bag cultivation of single-ascospore heterokaryotic isolations.Ninety-seven single-ascospore heterokaryons were cultivated in the field by using the method of spawn-bag-cultivation.The results showed that the fruiting ratio of singleascospore heterokaryons was high.For 47 strains of M.importuna,only one had no fruiting,with 97.8% fruiting ratio,the yield for highest-yield strain was 1062 g/m~2.Two of the 50 strains of M.sextelata had no fruiting,with 96.0% fruiting ratio was,the yield of the highest-yield strain was 581 g/m~2.4.Preliminary screening on the formula and the quantity of spawn-bag.Twenty treatments of filed cultivation with different formulas(the content of wheat grains were 0,25,50,75 and 100% respectively,and the other were sawdust,named M0,M1,M2,M3 and M4)and different spawn-bag numbers(8,12,14 and 16)were carried out by using three strains YAASJNLM1-31,YAASJNLM6-6 and YAASJNLM6-20 of M.sextelata.The results showed that the yield of 16 spawn-bags with M3 formula was higher than others for strain YAASJNLM1-31 and YAASJNLM6-20,and their yields were 359.3g/m~2 and 180.7 g/m~2,respectively,the yield of 14 spawn-bags with formula M3 for strain YAASJNLM6-6 was higher than others,and its yield was 228.0 g/m~2.5.The relationship between nutrition in spawn-bag and morel yield.The total dry weight,organic carbon,total nitrogen,total phosphorus and total potassium of the before-inoculating and after-harvesting substrates in spawn-bags for every treatment of strain YAASJNLM1-31 were determined,and the consumption proportion of spawn-bag substrate and the consumption quantities of the above four nutrients were calculated.The results showed that there was a great difference in the proportion of spawn-bag substrate consumption among different treatments(40.81% ～ 64.75%).The proportions of substrate consumption of pure sawdust formula and pure wheat grain formula were40.81%～41.73% and 49.65%～50.44% respectively.The morel yield of spawn-bag cultivation was significantly positive correlation with the consumptions of organic carbon,total nitrogen,total phosphorus and total potassium in spawn-bag substrate,and the Pearson’s correlation coefficients were 0.810,0.652,0.951 and 0.574,respectively.6.The optimization of spawn-bag formula.Nine spawn-bag formulas(MM1,MM2,MM3,MM4,MCK,MY1,MY2,MY3 and MY4)were designed with wheat,sawdust and corncob as raw materials,and field cultivation experiments were conducted with M.importuna strain 36 and M.sextelata strain 75.The results showed that for strain36,the yield of pure wheat formula MCK was higher than others with 375 g/m~2,while the yields of strain 75 with the formulas MCK,MY2 and MY3 were higher than others,and the yields were 389 g/m~2,396 g/m~2 and 401 g/m~2,respectively.