| Maize and potato are the two most important food crops in the eastern of Gansu province,The energy resources of this area were insufficient to plant two crops a year. It can effectively improve the utilization rate of resources and land, and increase the economic and social benefits by multiple cropping different varieties of corn and potato. Multiple cropping can improve the utilization of light and energy. The field experiment was conducted to evaluate photosynthetic characteristics, yield and water use efficiency of the different multiple cropping maize and potato varieties. The aim is to select the crop varieties with high efficiency utilization of water and highlights. The results of this study can provide theoretical support for harvested of three times every two years in eastern of Gansu. The main results of experimental were including:1. The net photosynthetic rate(Pn) and stomatal conductance(Gs) of different corn varieties after flowering were gradually decreased with the crop growth, but the change trend of intercellular CO2 concentration(Ci) was opposite compared to the other varieties. The Pn and Gs of Demeiya1 and Demeiya 2 at 50 d after flowering were always higher than other varieties and the change trend of photosynthetic rate and stomatal conductance of each type was consistent.The Ci of Jindong 302 at 50 d after flowering was highest. It was 306.7μmol?mol-1.2. The Pn, Gs, Ci and transpiration rate(Tr) of different potato varieties had significant differences. The Pn, Gs, Tr of Qingshu 9 were highest. They were 29.9μmol CO2·m-2·s-1,0.4733μmol·m-2·s-1 and 5.98μmol·m-2·s-1, respectively. However, the Ci was lowest. The Pn, Gs,Tr of Longshu3 was lowest, but its Ci was highest.3. The dry matter accumulation of Jindun302 maize plants was highest, followed by Demeiya varieties. The leaf area index of Demeiya2 was higher by 53.23% than CX350. The production performance were Demeiya 2 > Demeiya 1 >Xinyu54>Xinyu 40>Jindun 302. The dry matter accumulation of each potato varieties also increased with the potato growth. The dry matter was rapid accumulation from the tuber initiation to bulking stages of potato. The dry matter accumulation of Qingshu 9 was highest in every period, followed by Gannong5, which was higher than Longshu3 by 30.9%.4. The soil moisture content of different corn and potato varieties showed obvious change as the growth period. The surface soil moisture content was lower, which was raised with the increase of soil depth. Soil water content changed little under 100 cm soil layer. The soil moisture content of Demeiya2 was highest than other varieties in early growth stage. The soil moisture content of Jindun302 was highest in late growth stage. And that of Feiwuruita waslowest, followed by Qingshu9.5. The photosynthetic indexes had significant differences between different varieties. The photosynthetic ability in different potato varieties had the extremely significant difference. The Pn and Gs appeared very significant positive correlation, and the correlation coefficient was0.988**. Moreover, the correlation between the transpiration rate, photosynthetic rate and stomatal conductance expression were significantly positive. The correlation index of which was0.940** and 0.945***. The Ci showed significant negative correlation with Pn, Gs, and the Tr.The correlation coefficient were 0.912*, 0.860* and 0.734, respectively.6. We can see from the photosynthetic parameters, agronomic characters, yield and water use efficiency that Demeiya varieties was more suitable to the local double-cropping maize varieties, and followed was Xinyu series varieties. However, the optimal potato varieties was the Qingshu 9, and the secondly was the Gannongshu 5. |
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