Study On Nutritional Diagnosis And Fruit Quality Of Pecan Leaves In Northern Anhui And Jianghuai Regions

Pecan(Carya illinoensis)was widely introduced and planted in Anhui Province.【Objectives】This study provide scientific basis for the rational fertilization,yield improvement,quality enhancement and exploitation of pecan,which can promote the development of pecan industry.【 Methods 】 The main cultivars ‘Boni’,‘Mahan’,‘Weston’ and ‘Jinhua’ were selected from the northern Anhui and Jianghuai regions as study objects.In this study,leaf samples were collected at full leaf development stage and fruit filling stage to determine leaf mineral nutrient content;fruit yield was recorded and fruit samples were collected at fruit maturity stage;DRIS and DOP diagnostic methods were applied to diagnose pecan leaves to determine the order of fertilizer requirements;and fruit quality of different varieties of pecan was evaluated to determine the superior varieties.【Results】The main findings are as follows:1.There are many differences in mineral nutrient content of pecan leaves between its full leaf unfolding period and fruit filling period so its leaf nutritional diagnosis should be made according to its growing periods and apply fertilizers adequately.we can use the DRIS and DOP indices to figure out the order of fertilization of pecan woods with high production and low production in northern Anhui and Jianghuai Regions.During the full leaf unfolding period,pecan woods with low production lack Zn,Mn,Mg and Fe while the high production ones lack P,K and Fe.During the fruit filling period,the low production ones lack Mn,Mg and Ca while the high production ones lack P and Cu.Therefore,we apply element fertilizers to avoid wasting fertilizer according to what kinds of element pecan woods in northern Anhui and Jianghuai Regions lack,such as supplementary application or less application of macro-element N,P,K fertilizer.2.The standard deviation,coefficient of variation and nutrient imbalance index(NII and∑DOP)of mineral nutrients in leaves of pecan woods at different growing periods(the full leaf unfolding period and fruit filling period)of high yielding woods are lower than those of the low yielding ones,which indicates that the content of mineral nutrient in the high yielding woods is more stable than that of the low yielding woods.The results of DRIS method and DOP method are approximately the same but there are still some differences because of their different requirements.3.With respect to pecan fruit morphology,pecan varieties of ‘Boni’ and ‘Mahan’ in northern Anhui are better than those in Jianghuai Regions in terms of tree height,fruit diameter and single fruit weight.Among the fruit trait indexes,there are obvious differences between pecan varieties of these two areas in tree height,fruit diameter,fruit shape index,single fruit weight,kernel weight and kernel yield.The coefficient of variation of each index is in the order of single fruit weight > kernel weight > fruit shape index > fruit height > fruit diameter > kernel yield,among which ‘Mahan’ in northern Anhui has the best fruit traits,with a fruit height of 57.79 mm,a fruit diameter of 24.73 mm,a single fruit weight of 10.82 g and a kernel weight of 5.75 g.There are strong correlation among morphological indicators of pecan fruit.Therefore,the kernel weight and kernel yield could be derived from such indicators as the tree height,fruit diameter and single fruit weight and so on.4.Among the fruit inclusions,protein and fat differ obviously among different varieties,with an average protein content of 11.47 g/100 g and an average fat content of 67.61 g/100 g among the four varieties in northern Anhui and Jianghuai regions,and the NII was protein > fat.The highest protein content is ’Jinhua’ with 14.41 g/100 g and the highest fat content is ’Boni’ with ’Boni’ in Jianghuai regions at 73.11 g/100 g.The fatty acid fraction of pecan consists of three saturated fatty acids and five unsaturated fatty acids.There are some obvious differences in palmitic acid,stearic acid,oleic acid,linoleic acid and α-linolenic acid among different varieties,and the average order of fatty acid fraction of the four varieties in northern Anhui and Jianghuai Regions is oleic acid(59.14 %)> linoleic acid(30.26 %)> palmitic acid(6.34 %)> stearic acid(2.27 %)> α-linolenic acid(1.58 %)> cis-11-eicosanoic acid(0.233 %)> arachidonic acid(0.11 %)> palmitic acid(0.065 %).In northern Anhui,the highest oleic acid content reaches 67.71 % for ‘Pawnee’,the highest linoleic acid content reaches 37.87 % for ‘Mahan’ and the highest palmitic acid content reaches 6.86 % for ‘Western’.In Jianghuai Regions,the highest stearic acid content reaches 2.75 % for ‘Boni’,the highest content ofα-linolenic acid reaches 2.07 %for ’Western’.In Jianghuai Regions,the highest content of cis-11-eicosanoic acid reaches0.245 % for ‘Boni’.In northern Anhui,the highest content of arachidonic acid reaches0.17 % for ‘Mahan’ and the highest content of palmitic acid reaches 0.079 % for ‘Jinhua’.5.Principal component analysis showed that both fruit morphology and fruit inclusions of pecan were important indicators for evaluating fruit quality,which could lead to the following comprehensive fruit quality of pecan: in terms of varieties,the best comprehensive performance is ‘Boni’ followed by ‘Mahan’,‘Weston’ and ‘Jinhua’;in terms of different regions,in the northern Anhui region ‘Boni’ boasts the best comprehensive performance,followed by ‘Mahan’ and ‘Weston’;in the Jianghuai region‘Mahan’ boasts the best comprehensive performance,followed by ‘Boni’ and ‘Jinhua’.【Conclusion】This study identified the key fertilization period and the suitable period for sampling diagnosis of pecan,and derived the nutritional diagnosis parameters and clarified the fertilization sequence,which provided theoretical support for fertilization and nutritional diagnosis of pecan;meanwhile,this study identified regional dominant varieties through comprehensive analysis of fruit quality,which provides a scientific basis for the development and utilization of pecans.