The Study On Selectting The Appropriate Choice Of Varieties Of Potato/Maize Interopping Sytems

To discuss the light energy utilization and the differences of yield inside the potato intercropped with maize group under the same field configuration, and select the best combination of potato and maize varieties,it provides the practical basis on the increasing of production and utilization potatoes/maize relay-cropping system. This experiment on the basis of potato/maize interplanting row proportion of 2:1, the southwest region representative six types of potato varieties and four types maize varieties were combined separately to interplant and 2 factors split plot experiment was carried out. Potato in the potato/maize intercropping system was studied in agronomic traits, fluorescent light environment, photosynthetic physiological characteristics, physiological characteristics, RuBP carboxylase and physiological activity of sucrose phosphate synthase SPS, dry plant accumulation and its impact on production. The main research achivements are as follows:1. The influence on potato plant height, stem diameter and leaf area indexThe plant height and stem diameter of different potato varieties are difference significantly, due to the different characteristics of potato varieties. The leaf area index(LAR) of mid-maturity potato varieties show first rises then falls with the growth period, while LAR of late potato variety show the increasing trend. LAR of Yu potato 1 is hightest,however LAR of E potato 1 and Dian potao 1 is lowest.The differences of potato plant height are significant under different maize varieties,with mid-maturity,mid-diffusion type maize varieties in potato plant the lowest.The impact of maize maturity is larger than plant type, while it had no significant effect on potato stem diameter. It had significant effect on LAI of potato, with late ripe,compact type maize varieties in potato plant the hightest. LAI is increasing significantly.2. Effects on potato photosynthetic leaf chlorophyll contentMeasurement on potato leaves of each stage demonstrated that potato leaf chla,chlb,chla+chlb cotent were first flatten out after rapid growth and then slightly lower.but the mid-maturity shows first rises then falls,late potato shows sustained growth trend.The Maize varieties significantly influence the contents of potato leaf chla, Chlb and chla+Chlb,with the mid-maturity and semi-compact maize varieties is hightest.3. Effects on potato light distribution and light interceptionMeasurement on layering and quantile of potatoes’ PAR demonstrated that differences existed among PAR in terms of time and space and changed in a "W-shaped" manner along with the change of measuring sites. The vertical structure of potatoes, with upper and middle parts of canopy intercepting the most.At the same time,PAR interception is also influences by potato, maize varieties,with the expansion of potato plant type,the light the whole canopy receive are low,and mid-maturity higher than lat on the middle and upper parts,but is lower on the bottom. PAR interception of potato is lower with mid-maturity and mid-compact maize varieties.4. Influence on photosynthetic indexes of potatoesPotato’s Pn, Gs, Tr decrease as the leave position decreases, and Ci increases as the leave position decreases. Pn, Gs and Tr of potatoes in the same maturity and different plant type are lower in diffusion type leave position, and Ci is higher. Pn, Gs and Tr of mid-maturity potato are higher than them of late-maturity potato, and Ci is lower. Pn, Gs and Tr of all potato leave position which intercropped with mid-maturity and mid-compact maize varieties are lower, and Ci is higher.5. Influence on fluorescence parameters of potatoesFluorescence parameters are significant different between different varieties of potato. Fv/Fm, ETR and qP decrease as potato plant type’s extension, and qN increases. Fv/Fm, ETR and qP are lower with intercropped with mid-maturity and semi-compact maize, and qN is just opposite.6. Influence on activity of potato RUBP carboxylase and SPSActivity of RUBP carboxylase and SPS are lower with intercropped with mid-maturity and semi-compact maize. Activity of RUBP carboxylase decrease as potato plant type’s extension, mid-maturity potato is higher. Activity of SPS increases as potato plant type’s extension in the mid-maturity potato, and late-maturity potato decreases. Activity of SPS with mid-maturity is higher than late-maturity under the expansion of potato plant, Upright potato and Semi-diffusion potato are opposite.7. Influence on dry plant tissue accumulation and yieldIt is significantly different among the dry matter accumulation in each organ of different potato varieties in the whole growth period.The dry matter accumulation in stem and leaves of mid-maturity varieties increases first and then decreases as the growth period’s advance, while late potato varieties show the increasing trend. The dry matter accumulation in tuber of all the potato varieties increase continually. Maize varieties have effect on dry matter accumulation of each potato organ.It is lowest intercropped with the late and Semi-compact maize especially.What is more, significant difference was found in different varieties of potato. Mid-maturity potato yield is higher than late potato yield decreases as plant type’s extension. Maize varieties also have effect on potato yield,It is lowest intercropped with the mid-maturity and semi-compact maize especially. The composite yield of Yu potato 1, E potato 5 intercropped with YuDan 15 are highest, they are 945.25kg/667m2,967.80 kg/667m2 in significant differences with other treatment.