Studies On Pollinating Varieties Screening,Postharvest Storage And Photosynthetic Characters Of Kiwifruit

Kiwifruit is woody vine fruit tree which is native to our country.Being dioecious,kiwifruit shows an obvious xenia effect which has important influence on fruit quality.To provide the basis of choosing the best adaptive varieties,influence of xenia effect on fruit quality of kiwifruit was studied.By the reason of thin skin and juiceful texture,after harvest for about two weeks,kiwifruit would soften and even rot.So it is urgent to seek effective storage methods to delay fruit softening and rot,and lengthen storage period.In addition,the photosynthesis duration and efficiency of kiwifruit tree determine the photosynthetic products accumulation.Photosynthetic characters are different with various varieties,climates and growing environments.So it is necessary to study the photosynthetic characters of kiwifruit.The main research contents are as follows:1.Xenia effect in kiwifruit was studied.’Hayward’,’Xuxiang’ and ’Xianglv’ as females were pollinated respectively with pollens from ’Riyin No.1’,’Hongyang’,’Riyin No.2’,’Xuxiang’,’Huangjinguo’ and ’Tomuri’.20 pollination combinations were set with natural pollination as control.For each pollination combination,fruit setting rate,single fruit weight,vertical and horizontal stems,fruit shape index,hardness,soluble solid,tartaric acid,Vc,fresh color,thousand seed weight,seed number and shape were determined.The results showed that different pollination combinations showed obvious differences in above fruit traits.So xenia influenced fruit setting,external and internal fruit qualities and seed characters of kiwifruit.In actual production seeking the most adaptive pollinating variety is very important.2.Fruits of ’Hayward’ and ’Xuxiang’ as objects,five treatments including room temperature,room temperature + ethylene,room temperature + potassium permanganate,low temperature,and low temperature + potassium permanganate were tested for fruit storage.The results showed that ethylene had positive effect in promoting fruit softening,potassium permanganate treatment under room temperature showed little effect in delaying fruit softening,low temperature and low temperature + potassium permanganate both delayed fruit softening and lengthened storage period,and low temperature + potassium permanganate showed better result.In actual production,low temperature treatment is simpler than low temperature + potassium permanganate treatment while both treatments have similar effects in maintaining fruit quality and lengthening storage period.3.Photosynthetic characters of f ’Hongyang’,’Hayward’ and ’Xuxiang’ under field conditions were investigated.Daily variation of net photosynthetic rate,transpiration rate,stomatal conductance and intercellular CO₂ concentration were determined.Through studying photosynthetic characters of different varieties,mechanisms causing "midday depression" phenomenon were explored.The results showed that "midday depression" in’Xuxiang’ and ’Hayward’ belonged to "midday depression" limitation pattern,and covering shading net or cooling through sprinkling irrigation can limit "midday depression" phenomenon."midday depression" in ’Hongyang’was caused by stomatal limitation.