| Water shortage and marssonina apple blotch are the important reasons limited the development of apple industry in China.Arid and semi arid areas in Northwest China are the main producing areas of apple,but the lack of fresh water resources,restricted the development of apple industry.Marssonina apple blotch induced apple early defoliation and chemical methods was generally used to prevent and control it,but emergence of resistance strain make it difficult to control this disease through chemical measure.Therefore,it had great scientific significance to study the causes of drought resistance and disease resistance of apple and cultivate drought-resistant and disease-resistant varieties for the sustainable development of apple industry.It is still an urgent problem to be solved at present.In this study,19 Fuji strains cultivars,6 hybrid clones and 6 control varieties were treated with drought-resistant and inoculated with brown spot.The physiological indexes were evaluated,and the drought-Resistant varieties of marssonina apple blotch,Drought-resistant and disease-resistant varieties were expected to get through evaluating physiological indexes and provided theoretical basis.The main results of this paper are as follows:1.The change of conductivity of 19 cultivars in Fuji was higher than that in control,system but the different was not significant.Indicated the damage of plant cells was not obvious enough after drought treatment and it seemed that the varieties of Fuji had better drought resistance.After rehydration,the conductivity of 19 varieties showed a downward trend,but lower than the initial value,indicating that the drought caused a certain degree of damage to the cells.The content of MDA in leaves of 19 Fuji varieties raised not obviously after drought treatment,and the drought resistance of Fuji system was also explained.The net photosynthetic rate(Pn),transpiration rate(Tr)and stomatal conductance(gs)of the leaves showed a decreasing trend after drought treatment.The results of drought resistance are as follows: Yanfu No.10>Gongteng Fuji>Long Fu short sticks>Naganofuji No.2>Ryoka no Kisetsu > Extended red > Fuji champion > Fujiko > Summer incense > Miyazaki short >Heisei>Yuhua early rich>Fuji excellent system>Kiku>Senshu>Morning mist>Spike>Hongxiang>Love fragrance2.The results showed that the yield of 12 varieties under hybridization and control group showed a increasing trend after drought treatment,but the increase of different varieties was different.The Pn,Tr and gs of the leaves showed a decreasing trend after drought treatment.The results showed that the drought resistance of Pinova was stronger than that of other cultivars,and the overall resistance distribution of hybrid hybrids was not uniform,and the conductivity of some varieties was lower than that of the control group.The results of drought resistance are as follows: Pinova>South 10-3>Qinguan>South 39-66>North 17-1>North 19-147 > Western 83-92 > North 49-152 > Honeycrisp > Ruixue > Ruiyang > Naganofuji No.2.3.There were significant differences in the resistance to brown spot disease among varieties Miyaji Fuji,one of the Fuji varieties had the strongest resistance to brown spot disease,on the contrary Senshu was the worst susceptible.Disease resistance comparison results are as follows: Gongteng Fuji>Ryoka no Kisetsu> Fuji champion>Fuji excellent system>Morning mist>Long Fu short sticks >Yanfu No.10>Miyazaki short>Kiku>Extended red > Love fragrance > Fujiko > Naganofuji No.2.> Summer incense > Yuhua early rich>Hongxiang Heisei>Spike>Senshu.4.There were significant differences in the resistance of apple hybrids to apple brown spot in six hybrid varieties and six control groups.Honeycrisp resistance to disease was the strongest,West 83-92 resistance was the weakest.There were only twenty varieties of leaves in all the two hybrids,accounting for 33.33% of the hybrids,which indicated that the hybrid resistance was stable.Disease resistance comparison results are as follows: Honeycrisp>North 19-147 > South 10-3 > Naganofuji No.2 > North 49-152 > Ruixue > Qinguan >Ruiyang>Pinova>South 39-66>North 17-1>Western 83-92. |
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