【作者】 赵慧；

【导师】 李敏权；

【作者基本信息】 甘肃农业大学 ， 植物病理学， 2009， 硕士

【摘要】 1、苜蓿根及根颈镰刀菌的种群结构苜蓿生育期内,分不同季节,从甘肃省景泰县灌区发病苜蓿田采取发病样本,采用常规室内组织分离技术,进行镰刀菌的初步分离。分离所得镰刀菌在WA上进行单孢分离,转至PSA和PDA上进行性状观察,测量生长率,并在CLA上进行诱导产孢。经鉴定分别属于9个种的257株镰刀菌分离物,其中茄病镰孢(F. solani)为最优势种,分离到93株,分离频率达36.41%;其次为半裸镰孢(F. semitectium),镰状镰孢(F.fusarioides)和尖镰孢(F. oxysporium),分离频率分别为25.27%,10.20%, 8.89%。2、镰刀菌种群的时间变化苜蓿不同生长时期,根及根颈镰刀菌的种群大小不同,但每个季节的优势种均为茄病镰孢(F. solani)。4月份返青初期所采样本,分离得到67株镰刀菌; 6月生长盛期分离得到52株;8月开花期分离得到99株;10月收刈期分离得到39株。3、镰刀菌的致病性测定采用室内平皿接种法,在品种德宝上进行致病性测定,不同种的镰刀菌之间致病性有差异,同种镰刀菌,不同菌株之间致病性也有差异。其中茄病镰孢,半裸镰孢,尖镰孢,锐顶镰孢,弯角镰孢各菌株致病性和对照相比均能达到显著水平,而镰状镰孢15# ,燕麦5#,木贼1#、2# ,无孢组13#、14#、15#、16#的致病性和对照相比无显著差异,初步确定为弱致病菌株。而镰状镰孢(F.fusarioides)、弯角镰孢(F.camptoceras)能引起苜蓿根及根颈腐烂病是苜蓿上的首次报道。4、弱致病性镰刀菌对其他苜蓿品种的致病性研究选取在苜蓿品种“德宝”上表现为非(弱)致病性的8个菌株:镰状镰孢15# ,燕麦5#,木贼1#、2# ,无孢组13#、14#、15#、16#。在新疆大叶、阿尔冈金、金皇后、甘农3号、苜蓿王、牧歌、德里兰德、猎人河、安古利、陕西矩苜蓿等10个品种上,采用平皿法测定苜蓿不同品种的致病性。试验发现8个弱致病性菌株在10个品种上的致病性存在差异,但整体来说均表现弱致病性,其中无孢组14#和镰状14#基本为无致病性菌株;5、弱毒镰刀菌菌株对苜蓿幼苗生长的影响8个弱致病镰刀菌菌株处理10个不同品种苜蓿后,各处理幼苗胚根的长度均比对照短,且差异显著。无孢13#菌株能引起各不同品种苜蓿幼苗鲜重的增加,且与对照差异显著;其他菌株无显著增加。6、非致病性镰刀菌控制苜蓿幼苗腐烂病的研究接种非致病性镰刀菌菌株,会对强致病菌株的致病性产生抑制作用,但是属于同一种的弱致病性镰状镰孢对强致病性镰状镰孢并无抑制作用,且先接种弱(非)致病菌株,后接种强致病菌株,其致病性作用比同时接种弱(非)致病性菌株和强致病性菌株要明显。更多还原

【Abstract】 1. Population structure of Fusarium.spp on Alfalfa crown and rootAlfalfa diease samples were collected from Gansu Hexi Jintai irrigation areas, in different seasons .and 257 isolates of Fusarium strains were gained,they had been identified as 9 species by the growth rate and the characteristics on the PSA, PDA and CLA. The dominant specie was the Fusarium solani. 93 isolates of Fusarium solani were gotten and its isolate frequency was 36.41%. Other main species were F. semitectium F. fusarioides, and F.oxysporoum, the isolate frequencies were 25.27%, 10.20%, and 8.89% respectively.2. The variety of Alfalfa crown and root Fusarium populationThe population of Fusarium changed among the different growth period of alfalfa, The dominant specie was aways the Fusarium solani. 67 isolates of Fusarium were obtained in the April samples.52,99 and 39 isolates of Fusarium were respectively obtained in June August October samples.3. The pathogenicity of Fusarium spp.Different Fusarium species had the different pathogenic, and different strains had differences in pathogenicity through the plate inoculation method, in the alfalfa variety of Debao.All of the stains of Fusarium solani. F. semitectium. F.oxysporoum. F.acuminatum. and F. camptoceras were the pathogenic isolates.But F. fusarioides15#. F.avenaceum5#, F. equiseti1# , 2# and F.spp13#,14#,15#, 16# were the weak pathogenic or non-pathogenic isolates. F fusarioides and F.camptoceras causing the crown and root rot of alfalfa were the first record.4. Pathogenicity of weak pathogenic Fusarium spp. on varities of alfalfaWeak pathogenic isolates on Debao showed different pathogenicity on other ten varieties, Most of them showed the weak pathogenicity, F.spp14# and F. fusarioides 14# were the non-pathogenicity. 5. Effect of seedling growth by non-pathogenic Fusarium.spp.10 different alfalfa varieties inoculation by weak pathogenic and non-pathogenic isolates ,The result showed all of the treated seedlings radicle length were short than comparison.Only the F.spp13# could promoted the quantities of radicle siginificiently different.The others could not.6. Studied on Non-pathogenic Fusarium control seedling rotUsing solution of weak-pathogenic and non-pathogenic Fusarium.spp germinated the seed of alfalfa .It could control the Fusarium seedling rot in the plate.But meanwhile we found the weak pathogenic and non-pathogenic stains could enlarge the distructure same pathogenic Fusarium species.更多还原