不同熟性棉花品种冠层温度分布特点

Characterization of canopy temperature distribution in different maturity types of cotton varieties

【目的】明确不同类型棉花品种冠层温度的分布特点,探究冠层温度与光合特性之间的关系,寻求判断棉花熟性的可能指标。【方法】选择6个常用的供试棉花品种,利用搭载热红外测温仪的无人机获取棉花花铃期冠层温度的数字图像,同时测定同一时间段的蒸腾速率、气孔导度等光合指标。【结果】中棉所50不同部位气冠温差表现为上层>下层>中层,中棉所60则正好相反。在同一天中,6个棉花品种表现为13:30的冠层温度大于10:30的冠层温度。此外,不同类型品种叶片蒸腾速率与气孔导度呈正相关,冠层温度和蒸腾速率呈负相关。通过聚类分析得出,在欧式距离12.5处,6个品种可以聚类成2类。在欧式距离5处,每一类还可分为2个亚类,其中第Ⅰ类的第一亚类包括中棉所60和冀棉研228,第二亚类仅有中棉所3799;第Ⅱ类的第一亚类包括中棉所50和通骞一号,第二亚类仅有0式品系。【结论】不同棉花品种冠层温度的变化规律不同。结合冠层温度和光合指标对棉花品种进行聚类分组与其基于生育期长短的熟性分组大致相同。

[Objective]The distribution characteristics of canopy temperature in different types of cotton varieties were clarified;the relationship between canopy temperature and photosynthetic characteristics was explored,and the possible index for evaluating cotton maturity was identified.[Method]Six cotton varieties were selected,and the digital images of canopy temperature were obtained by using UAV(Unmanned aerial vehicle)carried thermal infrared thermometer from the flowering to the first boll opening period.Meanwhile,the transpiration rate,stomatal conductance and other photosynthetic indexes in the same period of time were measured.[Result]The results showed that the temperature depression of different levels of CCRI 50 were in the following order:the upper layer>the lower layer>the middle layer,and CCRI 60 is just the opposite.In the same day,of all cotton varieties,canopy temperature at 13:30 was greater than 10:30.In addition,transpiration rate of different types of cultivars was positively correlated with stomatal conductance and negatively correlated with canopy temperature.At the Euclidean distance of 12.5,six cultivars could be clustered into two categories.At the Euclidean distance of 5,each category could be divided into two subcategories by the clustering analysis.The two subclasses within the first category were as follow,the first subclass:CCRI 60 and Ji 228;the second subclass:CCRI 3799.The two subclasses within the second category were as follow,the first subclass:CCRI 50 and TQ No.1;the second subclass:0 Shi.[Conclusion]The change of canopy temperature of different cotton varieties was different.The cluster grouping of cotton varieties based on canopy temperature and photosynthetic index roughly correspond to the maturity types according to the growth period.