Analysis Of Xeromorphic Structure And Disease Resistance Of 12 Poplar Clones

Using 12 clones of poplar as experimental materials(84K,I-101,107,A23,A39,A50,A54,La,Pa,Qg,Ta and Ti),the physiological indexes of seedlings of each clones were determined: The drought resistance of 12 clones of poplar were evaluated based on leaf anatomy;The disease resistance to black spot disease and leaf blight of 12 poplar clones at seedling stage was carried out on,the infection rate,susceptibility index and relative susceptibility index of 12 clones of poplar were analyzed;And inoculation of Botryosphaeria canker was carried out in 12 poplar clones,the incubation period and peak period of pathogenic bacteria were observed,and the incidence and susceptibility index of asexual lines were calculated,to compare the resistance of asexual lines to ulcerative disease,to provide theoretical basis for breeding and resource utilization of new poplar varieties.The results were as follows:1.Drought capacity assessment The mature leaves of 1-year-old cuttings of poplar clones 84 K,I-101,107,A23,A39,A50,A54,La,Pa,Qg,Ta and Ti were compared 7 drought structural indexes by conventional paraffin sectioning method,including cuticle thickness,upper epidermis thickness,lower epidermis thickness,leaf thickness,main vein thickness,palisade tissue thickness and leaf tissue structure tightness(CTR).Using single factor ANOVA to compare the differences of 7 drought indexes among each asexual system,using correlation analysis to judge the correlation degree among each index,using principal component analysis to screen the main indexes affecting drought resistance.Finally,the drought resistance of 12 poplar clones was evaluated by fuzzy mathematics membership function method.There were significant differences among 7 drought resistant structural indexes of 12 poplar clones,the amplitude of cuticle thickness,upper epidermis thickness,lower epidermis thickness,leaf thickness,main vein thickness,palisade tissue thickness and leaf tissue structure tightness(CTR)is 1.94-17.07 μm,5.82-26.23 μm,3.28-18.96μm,39.62-201.59 μm,496.99-1712.35 μm,25.53-86.94 μm and 27%-66%.The coefficients of variation were 40.11%,49.02%,50.08%,39.13%,32.04%,27.87% and 59.09%.The results of correlation analysis show that except there was no significant correlation between cuticle thickness and upper epidermis thickness,lower epidermis thickness,main vein thickness,CTR and between the thickness of palisade tissue and lower epidermis,the correlation between other indexes was extremely significant,and 3 indexes of cuticle thickness,leaf thickness and leaf tissue structure tightness(CTR),were selected by principal component analysis.Using membership function method,the drought resistance of 12 poplar clones was sorted as follows: A50>Qg>Ti>A23>La>107>Ta>A54>I-101>A39>84K>Pa.2.Evaluation of anti-black spot and leaf blight Under the condition of natural disease,poplar A23 and A50 were resistant to black spot,black poplar Pa and Ti were resistant to black spot,poplar A23、A39 and A50 were highly resistant to leaf blight,A54 to leaf blight,and black poplar Pa、Ti、Qg、La、Ta were highly resistant to leaf blight.The asexual A23、A50 、 Pa and Ti have good resistance to black spot and leaf blight,and can be used to popularize new poplar varieties with good rapid growth and disease resistance.3.Evaluation of resistance to Botryosphaeria dothidea The resistance of 12 poplar clones to ulcerative disease was determined by indoor inoculation of Botryosphaeria dothidea.As a result,the clones A39,Qg,Ti belongs to high resistance clones,the average susceptibility index was 1.23%,11.44% and 4.57% respectively;The A23,A50,Ta,84 K and I-101 of the clones are resistant clones,the average susceptibility index was23.34%,42.9%,37.5%,28.75% and 33.3%,respectively;Clones A54 belong to susceptible clones,The average susceptibility index was 57.2 %;La,Pa and 107 are highly insensitive,The average susceptibility index was 69.05%,83.39% and 85.03%,respectively.A relatively low susceptibility index A39,Qg,Ti the sexless,It can be used as the best material for breeding the asexual line of new Populus tomentosa.