Study On Canopy Temperature Of Peanut And Physiological Characteristics

The study continuously observed the canopy temperature of 12 big-fruit type peanut varieties with infrared thermometer, and the diurnal fluctuation of canopy temperature, surface temperature, inter-plant illuminance, dry matter accumulation of legume and a series of parameters of physiological metabolize from fruiting period to filling-legume, and investigated and analyzed some agricultural characters in 2006 and 2007. The results showed that the canopy temperatures of different peanut varieties population were markedly different, some were high and some were low. The most of difference points of canopy temperatures of Yuhua153, Yuhua9331were above the zero-scale-mark, and most of them of Puhua9506, Kainong41 and Biaohua2 were under the zero-scale-mark, and this phenomenon was more obvious in the late stage of growth. So, we regarded the former and the CK Luhua11 as cold peanut and the latter as warm peanut.The differences of the diurnal fluctuation of canopy temperatures and surface temperature between cold peanut and warm peanut were the most at 13:00-15:00,the temperature of cold peanut was low and warm peanut was high, and the difference was more and more big. The diurnal fluctuations of inter-plant illuminance in different layers were unimodal curves and the peak values appeared at 12:00-14:00; The difference of canopy illuminance between cold peanut and warm peanut was not clear, and the difference where 1/2 height of plant and 0.02m height of plant were not clear in fruiting period, but they were clear in filling-legume, the illuminance of warm peanut was higher obviously than cold peanut with lays lowed. These indicated warm peanut was more effete than cold peanut and luminousness was higher during late period of growth, this maybe a important cause that warm peanut had a higher temperature.After the middle of fruiting period, chlorophyll content, soluble protein content, soluble sugar content of the function leaves of cold peanut caulis and NR activity, SOD activity, CAT activity were higher warm peanut, especially at the late stage of growth, enzyme activity of some warm peanut varieties had not been detected, but enzyme activity of cold peanut was still high; the MDA content of cold peanut was lower and the rate of accumulation was slower than warm peanut. These illustrated that physiology metabolize activity of cold peanut was higher, the capacity of cleaning away active oxygen was stronger, panniculus adiposus overoxidation was slighter and not easy to be premature senility, so, it could maintain larger greenery area and longer photosynthesis to offer strong material flow to fill grain, that was favorable for increasing yield.The analysis to the dry matter accumulation of peanut showed that the time of dry matter fast accumulation of cold peanut was longer 4.1d and the accumulation rate was faster 0.054g·zhu-1·d-1 than warm peanut, it was propitious to form more economic outputs. That was also the direct reason that cold peanut was strong in physiology activity.The correlation analysis showed that height of caulis, the number of branches, length of lateral branches, ratio of full pods and ratio of having economic yield had negative correlation with canopy temperature. So, height of caulis was higher, the number of branches was more, length of lateral branches was longer, and the canopy temperature was lower, and lower canopy temperature was propitious to increase ratio of full pods and ratio of having economic yield pods. Path analysis indicated ulteriorly that the number of branches and length of lateral branches made an impact on canopy temperature mainly through height of caulis.The correlation analysis between physiological characteristics, canopy temperature and yield showed that ratio of full pods, no. of pods per plant, weight per 100 pods, weight per 100 kernels, rate out of kernels had an important effect on yield, the correlations were r=0.5606**,r=0.4226*,r=0.4956*, r=0.4568* respectively; It was little that the effect of no. of branches,length of primary branch,height of main axis,ratio of having economic yield pods and canopy temperature on yield. 4 characteristics height of main axis, No. of pods per plant,Weight per 100 kernels and canopy temperature that had an essencial effect on yield were chosen by Stpwise. The path analysis indicated ulteriorly that the derict selection effect of no. of pods per plant and weight per 100 kernels were maximal(Px4→y=0.70762, Px6→y=0.69390),but the derict selection effect of height of main axis and canopy temperature were small relatively(Px3→y=-0.33481, Px10→y=-0.34210),and their effect were negative. So we should take no. of pods per plant and weight per 100 kernels as important indexes when we choose and breed peanut varieties.There are a series of excellent characters for cold peanut and these characters are very important for planting and breeding of peanut. There are copious quantities of peanut germ plasm resource and their characters make a great deal of difference, therefore, we breed and extend peanut varieties that have a low canopy temperature whit canopy temperature would redound to stably increase peanut yield, and ulteriorly impulse the development of peanut industry.