Studies On Drought Resistance Difference And Its Response To Drought Stress Of Main Peanut Varieties In Liaoning

Peanut is one of the three major crops in Liaoning, and there are about 3.5 billion square meter of peanut planting field annually. The main location is west and northwest of Liaoning. The peanut’s production is interfered by drought, especially in the stage of seeding and flowering, has been the major factor to make peanut’s production level lower or unstable. Our research by testing the main peanut planting species in Liaoning, and using the method of PEG6000 drought simulation test, to analysis the drought resistance of peanuts in germination stage. Basic on the results, select 6 of them, which have different drought resistant ability, by pot culture experiment, in the flowering stage of moderate drought stress, in order to analyze the changes of peanut index including root and aboveground morphological,physiological characteristics, yield, kernel quality.et to discuss the resistance level under drought condition. Based on our research, we can give direction and reference to improve the yield of peanut while in drought environment.Our major research is under following:1. seed germination rate (r=0.71**) and germination potential (r=0.54*) shows a positive correlation with GDRI. By testing the drought resistant ability, we find out that the luhuall, huayu22, jinhua 14, tieyinhual, nonghua5, have positive drought resistance, and fuhu10, baisha1016, yuanza9102 cannot stand drought environment.2. Drought stress can affect peanut’s root growth, the species with different drought resistant ability can express different characteristic. We compared fuhua10 and baisha1016: By extending the drought time in flowering stage, with drought resistant ability, increased root length and volume per plant of luhua11 and nonghua5, increased root surface area per plant of huayu22 and nonghua5, is the ultimate embodiment of insisted roots dry weight accumulation.Drought makes the water content decrease in root, and species with drought resistant ability decrease much less than the species without drought resistant ability. Our research shows that, under the drought stress, the species with drought resistant ability have advanced root system, and their roots can hold more water in drought environment, in order to help them absorb nutrient and water resources.Drought stress makes peanuts have higher main stem, longer branch length, larger area on each plant, the dry weight of stem and leaf, and the moisture content are obvious decrease. The species with drought resistant ability has longer branch length, larger leaf area, and higher moisture content on each leaf. luhual 1 has the longest branch length, and largest leaf area, and higher dry weight and moisture content on leaves; huayu22 has the highest dry weight and moisture content on leaves, which mean they can hold higher moisture on their aboveground while under drought stress.3. The decline of Gs was decreased and Ci decreased first,then increased, implying that the probable main factors for Pn decline were stomatal limitation at earlier stage of drought stress. During continuous drought affected stoma adjustment ability the probable main factors for Pn decline were non-stomatal limitation. The photosynthetic characteristics of huayu22、 luhual 1 and nonghua5 infection rates decreased slightly, showed stronger ability of retaining water, kept higher photosynthesis. Fv/Fm, ΦPSII and qP was a decreasing trend under drought stress. Huayu22 luhua11 and nonghua5 was less decreased,kept higher Fv/Fm, ΦPSII、 qP and NPQ. Prevented photoinhibition and photooxidation and sustained the normal function of photosynthetic structures.4. While drought stress extended, the activity of SOD, POD, and CAT from peanut’s functional leaves are decreasing, and then increasing, luhua11 and nonghua5 show s increased activity of SOD, POD, and CAT in the fifteenth day under drought stress. This stage from luhua11 and nonghua5 appeared much early than other species. On the other hand, in the late stage of drought stress, luhua11 and nonghua5’s activity of SOD, POD, and CAT increased larger range than the others. Under drought stress, the species with drought resistant ability can regulate their function, in order to adept the drought condition much early than the species without any drought resistance. With larger quantity of active SOD, POD, and CAT, and lower quantity of MDA shows that the active oxygen is less harmful targeting the leaf cells.5. The drought stress makes the number of pod,100-kenels weight and shelling percentage decreased. luhua11 and nongha5 have obvious higher number of pod per plant than the other species. By comparing with negative control, the decreasing percentage are 17% and 18％. In the results of 100-kenels weight, luhua11 and huayu22 have smaller interfere by drought stress, the 100-kenels weight decreased 19％and 17％than control group, and still much higher 100-kenels weight than the other species. By comparing the drought resistance level, our experimental data shows:huayu22>luhua11>nonghua5>fuhua10>huayul9> baisha1016.In the stage of flowering, drought environment can make most species of peanut have obvious lower fat and oleic acid content, and higher linoleic acid content. The results is the radio of O/L is much lower, which can influence peanut’s quality. Under the drought stress condition, the O/L of fuhualO has the largest decreased rate, but it is still obvious higher than the other species. The fuhualO may have some potential for improvement. By optimize fuhua10’s drought resistance, it can produce better yield and quality of peanut production.