| Because of the characteristics of high yield,good flavor,and good storage and transportation performance,the cultivation of Orah mandarin in China has exceeded133 thousand hectares and continues to grow since introduced in 2004.However,differences in exterior and interior fruit quality existed in different growing regions,and there is still a lack of research about it.Therfore,12 Orah mandarin orchards were used as test materials,and these orchards were located in 5 climatic regions,including tropical rainforests?Xishuangbanna and Jiangcheng of Yunnan province?,southern subtropics?Nanning of Guangxi province,Zhaoqing and Conghua of Guangdong province?,middle subtropics?Liuzhou and Guilin of Guangxi province?,dry-hot valley region?Xinping and Binchuan of Yunnan province?,and high humidity and long sunshine region?Meishan of Sichuan,Beibei and Zhongxian of Chongqing city?.The tree growth,fruit yield and quality in different climatic regions were studied to select the key meteorological factors affecting their performance in order to provide the basis for the proper planting of Orah mandarin in China.1.The general situation of climate,growth,and yield of Orah mandarin in different climate regionsBased on the statistics of the meteorological factors of five climatic regions in the past 30 years and the year of this test carried out,it was found that the annual sunshine hours in dry-hot valley area was the longest,the annual rainfall and relative humidity in tropical rainforests were the largest.And there was few hours of sunshine and high humidity in high humidity and low illumination area.The results of meteorological data during the experiment showed that the annual active accumulated temperature above10?,annual effective accumulated temperature above 10?and annual rainfall in southern subtropics,middle subtropics and tropical rainforest areas were all higher,the annual sunshine hours in dry-hot valley area was the largest,and the annual relative humidity in tropical rainforest was the largest.The July-August average temperature in Beibei and Zhongxian was the highest,which was above 30?.The monthly sunshine hours before harvest in Binchuan was the longest,which could reach 243.2h,while the monthly average relative humidity before harvest was the lowest,only 45.8%.The planting density of Orah mandarin?3-5 years old?in different areas ranged from 45 plants/667m2 to 110 plants/667m2,and the largest in Binchuan.The ranges of tree height,East-West canopycrown path and North-South canopycrown path were1.64?2.85 m,1.57?3.17 m and 1.63?2.96 m,respectively.All this in Nanning were the largest.The general trend was that the southern subtropics and middle subtropics were the largest,followed by tropical rainforest and dry-hot valley area,and the high humidity and low illumination area was the last.The trunk circumference of 5cm above graft union was 53.48?105.38 cm.The southern subtropics,middle subtropical and high humidity and low illumination area were all the larger,followed by tropical rain forest,and the hot and dry valley area was the last.The average yield range was 17.15?74.03 Kg/plant.The yield of 5-year-old trees in Nanning,Guilin and Liuzhou was higher,which of tropical rainforest and dry hot valley area was in the middle,and which of 4-year-old trees in high humidity and low illumination area was lower.The average area yield range was 944.19?3710.73Kg/667m2,which of middle subtropics,tropical rainforest and dry hot valley area was relatively large.And the high humidity and low illumination area was relatively lower.2.Fruit quality of Orah mandarin in different climatic regionsThe range of single fruit weight of Orah mandarin in different climatic regions was95.39?176.84g,and the largest in Xinping,the smallest in Zhongxian.The range of Fruit shape index ranged from 0.79 to 0.86,the largest in Jiangcheng,and the smallest in Zhaoqing.The peel thickness ranged from 2.25 mm to 4.60 mm,Xinping was the largest,and Liuzhou was the smallest.The ranges of peel and pulp hardness were7.87?12.96 N/mm2 and 0.62?1.11 N/mm2,respectively.And the edible rate and juice rate were 64.39?77.23%and 50.43?63.56%,respectively.The color parameter L of Orah mandarin in Jiangcheng area was significantly better than that in other areas,and the red degree a*of Beibei was the highest.The number of seeds ranged from 10.66 to22.55,the most in Binchuan and the least in Beibei.The content range of total soluble solids?TSS?was 11.83?16.16%,among which Binchuan fruit was the highest,followed by Liuzhou and Meishan.The content of titratable acid?TA?ranged from0.35?0.77%,the highest in Binchuan and the lowest in Guilin.The content of vitamin C was 16.35-24.11 mg/100mL,and Zhongxian was the highest,followed by Meishan and Beibei.The results of determination of primary metabolites revealed that sucrose was the main soluble sugar of Orah mandarin,which ranged from 35.23?74.91 mg·mL-1FJ,followed by fructose(18.72?61.51 mg·m L-1FJ)and glucose(15.29?54.86 mg·mL-1FJ).The content of sucrose in Binchuan was the highest,followed by Liuzhou.While the content of fructose and glucose in Beibei was all the highest.Citric acid was the main acid,the content range of which was 1.62?3.55 mg·mL-1FJ,followed by malic acid(1.31?3.28 mg·mL-1FJ).The content of citric acid was the highest in Meishan,The content of malic acid was the highest in Binchuan,the lowest of two acids in Zhaoqing.The content of proline in juice was the highest,ranging from 0.100 to1.179 mg·mL-1FJ,among which Meishan was the highest and Nanning was the lowest.The ranges of alanine,glycine,valine,serine and glutamic acid was 0.014?0.054 mg·mL-1FJ,0.009?0.032 mg·m L-1FJ,0.009?0.028 mg·m L-1FJ,0.011?0.041 mg·mL-1FJ,and 0.013?0.048 mg·mL-1FJ,respectively.The content of alanine,serine and glutamic acid was the highest in Binchuan,the highest of glycine in Zhongxian,and the highest of valine in Meishan.3.Comparative analysis on the comprehensive quality of Orah mandarin in different climatic regionsThe external quality,internal quality and comprehensive quality of Orah mandarin were analyzed using principal component analysis and cluster analysis.?1?External qualityAfter dimensionality reduction by PCA,two principal components were extracted.Their eigenvalues were 3.19 and 1.30,respectively.And the cumulative variance contribute rate reached 74.84%.The external quality of Orah mandarin in high humidity and light illumination area was the best,followed by dry-hot valley area and southern subtropics,and poor in tropical rainforests and southern subtropics.?2?Internal qualityAfter dimensionality reduction by PCA,five principal components were extracted.Their eigenvalues were 6.16,5.92,4.54,3.07 and 2.01,respectively.And the cumulative variance contribute rate reached 86.87%.The internal quality of Orah Mandarin in high humidity and light illumination area was the better,ranking higher,followed by dry-hot valley area,middle subtropics,and tropical rainforests,and which in southern subtropics was the worse.?3?Comprehensive qualityAfter dimensionality reduction by PCA,five principal components were extracted.Their eigenvalues were 9.14,6.89,4.86,3.23 and 2.20,respectively.And the cumulative variance contribute rate reached 84.95%.The comprehensive quality of Orah mandarin in high humidity and light illumination area and dry-hot valley area were the better,followed by tropical rainforests and middle subtropics,and poor in southern subtropics.4.The relationship between meteorological factors and fruit qualityTemperature was the most important factor affecting the quality of Orah mandarin.It was shown that the annual average temperature,the annual accumulated temperature above 10?and the average temperature in January were the most important meteorological factors affecting the fruit quality of Orah mandarin,followed by the annual relative humidity and the temperature difference between day-night in 1-3months before harvest,which could be used as the main indicator for the production of high-quality Orah mandarin. |
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