Construction Of Quality Evaluation System And High Luminous Efficiency,Labor Saving Tree System Exploration Of Sand Pear

Sand pear is an important fiuit tree species in our country,especially in southern area.It has many varieties and various resources.There are some of our country's own selective breeding,and some are introduced from foreign countries,like Japan and Korea.The study used 42 sand pear cultivars introduced from China and foreign countries to evaluate the quality of different cultivars.Combined with the fruit maturity,regarding strong adaptability,good quality as the main criteria,it screened out 8 Variety combinations included early,middle and late-maturing varieties;established a system for evaluating the quality of sand pear and provided a basis for the selection of Ningzhenyang hills and mountains of sand pear varieties.Based on labor-saving demand,it introduced two new cultivation patterns-two branches horizontal trellis systems and the 'joint tree' shape,and make comparison between the existing three branches horizontal trellis systems and V-shaped to obtain simple,labor-saving and mechanic tree model of sand pear pruning.The main research results are as follows:1.According to the 42 cultivars of sand pear for testing,Kousui,Cuiguan,Akitsuki,Wonhwang,Saigyoku and Whangkeumbae were best cultivars with proper shape in appearance.Kousui,Cuiguan,Wakahikari,Saigyoku,Akitsuki,Housui and Oushuuperformed excellent in inherent traits evaluations.The fruit quality of all tested cultivars can be divided into 4 groups according to the value of synthetic valuation(VSV).6 cultivars were in the first group,which VSV was lager than 0.60,included 3 early-maturing and 3 late-maturing.The types with the VSV ranged from 0.50 to 0.60 were the second group included one early-maturing,6 middle-maturing and 3 late-maturing.VSV ranged from 0.4 to 0.5 were the third group and included 14 cultivars,which were 2 early-maturing,6 middle-maturing and 6 late-maturing.The last group with VSV lower than 0.40 contained 4 early-maturing,5 middle-maturing and 3 late-maturing.The average value of weight per fruit was 434 g.The average content of soluble solids was 13.3%.The average content of soluble sugar was 97.27 mg·g-1.The average content of vitamin C was 2.95mg·g-1.The average content of stone cell was 8.88 mg·100g-1.The average content of titratable acidity was 1.38 mmol·100g-1.This study screened out 8 cultivars with greater adaptability and high quality based on comprehensive evaluation on appearance traits,inherent quality and economic traits.They are Kousui,Wakahikari,Cuiguan,Aikansui,Qiuyue,Caiyu,Housui and Wangqiu.The analysis of sugar components showed that the content of fructose was the highest,sucrose was the second,and glucose was the lowest.2.The fruit yield of the 'joint tree' is the highest among the four tree models and other three tree models were of obvious difference.The pruning time of the 'joint tree' is the lowest.It didn't need to do branches binding and not difficult.The variation of photosynthetic during a day of four tree forms were all expressed asymmetric bimodal curve.This suggested that it has obvious 'photosynthetic noon break'.The photosynthetic of the 'joint tree' was 16.21 ?mol·m-2·s-1.The photosynthetic of V-shaped was 15.24?mol·m-2·s-1.The photosynthetic of three branches horizontal trellis system was 13.15?mol·m-2·s-1.The photosynthetic of two branches horizontal trellis system was 12.66?mol·m-2·s-1.This suggested that the net photosynthetic rates of 'joint tree' were all higher than others during every period.The early yield of fruit per unit area of the four model trees-the 'joint tree,was 1.81 kg·m-2;V-shaped was 1.25 kg·m-2;the three branches horizontal trellis system was 1.22 kg·m-2;the two branches horizontal trellis system was 0.83 kg·m-2.So the early yield of fruit per unit area of the 'joint tree' was the highest.Soluble solids content of three branches horizontal trellis system was the highest levels of 13.8%,extremely significant different from the 'joint tree' shape,and significantly different from V-shaped.While the total soluble sugars content of three branches horizontal trellis system was the highest of 76.78 mg·g-1,reached an extremely significant level with the 'joint tree'shape and V-shaped.Vitamin C content,stone cell content and titratable acid content in four tree were not significantly different.Through the VSV of fruit quality for four tree shapes,the results of three branches horizontal trellis system was 0.56,the 'joint tree' shape was 0.55,two branches horizontal trellis system was 0.49,V-shaped was 0.44.