| This research was tried out field trials In 2008,in Wanyuan, Dazhou,Burley mid-maturing variety Dabai 1 and early maturing variety KY14×L8 were used to investigate the difference in temperature and humidity, main agronomic characters and the contents of quality and economic character during tobacco growth and air-curing at different altitudes. The results are as follows.1 The growth periods of two varieties became lengthened with the increase of altitude; while the average temperature during growth period decreased, and the relative humidity increased with the increase of altitute. As plants grew, the average temperature increased. At early growing stage, the relatie humidity is lower than those of at rap id growing stage and maturing stage, and there was no significant difference in relative humidity between rapid growing stage and maturing stage. The minimum and maximum air temperature occurred at 6: 00 and 15: 00 at all the three altitudes, and the minimum and maximum relative humidity also occurred at 6: 00 and 15: 00 at the three altitudes. With the increase of altitute,the effective accumulated temperature at almost all the stages of two varieties gradually decreased. The effective accumulated temperature required for root spreading stage of KY14×L8 was more than that for Dabai 1;that for rapid growing stage was no significant difference between the two varieties; while that formaturing stage, KY14×L8 required much less effective accumulated temperatures than Dabai 1.2 With the increase of altitude, the plant height,stem thickness, maximum leaf width of mid-season variety Dabai 1 decreased, the number of leaves increased in maturity stage, other periods o decreased, the maximum leaf length in root spreading stage and growing stage firstly increased,then decreased,while decreased rapidly in the maturity period. main agronomic characters of early maturing variety KY14×L8 in root spreading stagewere not changed obviously at different altitudes,the plant height,stem thickness, maximum leaf width and length of 1000 were best of all the altitudes in growing stage and maturing stage. Comparisons between different species were known that the growths between mid-season variet and early maturing variety were not significant at altitudes 700 and 1000m,the growths of KY14×L8 were better than that of Dabai 1 at altitude 1300m.3 Different altitudes had certain influence to the chemical composition and the economic character of mid-season variety and early maturing variety.The contents of nicotine and the total nitrogen presented certain regularity at different altitudes,With the increase of altitute,The contents of nicotine and alkaloid in upper and middle leaf of two Dabai 1 increased firstly, then decreased,while KY14×L8 decreased gradually.With the increase of altitute,The contents of total nitrogen in upper and middle leaf of two varieties decreased gradually.The contents of reductive sugar of two varieties at altitude 1300m were bigger than those at altitude 700m and 1000m, The contents of reductive sugar of mid-season variety Dabai 1 was greater than one,the others were appropriate.The contents of nicotine,alkaloid and the total nitrogen in upper leaf of two varieties were all bigger than those in middle leaf,but the content of potassium in upper leaf was smaller than that in middle leaf. the appearance quality and smoking quality of Dabai 1 at altitude 700m and KY14×L8 at altitude 1000m were harmonious.the color of leaves was red or yellow,and had open structure,the quantity of aroma was sufficient,the physiological strength was moderate.4 The duration of growth for early maturing variety were shorter than that of mid-mature variety at all the altitudes; while the differences in curing time between the two varieties at altitude 700 m were not significant. The days of curing for early maturing variety were shorter than that for mid-mature variety at altitudes 1000 and 1300 m. The days of growth and curing for mid-mature variety and early maturing variety at altitude 1300 m were longer than those at altitudes 700 and 1000m. With the increase of altitude, the temperatures at each growing and curing period decreased gradually, while relative humidity increased gradually. For early maturing variety, the fewer growing days made the harvesting time early, and put the curing in higher temperature, thus the progress of curing was accelerated, so at high altitude, the early maturing variety was most suitable, Mid-maturing variety grow better than early maturing variety and had greater yield and quality potential.5 The neophytadiene,class chromoplast alkanes,carotenoids of two varties were changed with the difference of altitude.The law of neutral aroma constituents of two varties at three altitudes was:neophytadiene |
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