Early Selection Of Drought-resistant Families Of Reaumuria Soongorica Based On Interannual Changes Of Physiological Indexes

The seeds were collected from three natural distribution areas of Reaumuria soongorica in Inner Mongolia,Gansu and Ningxia province,then planted in Wuwei Town,Wuwei City（38°24′N,103°9’E）for provenance tests.The Enzyme activity,osmotic adjustment substances,photosynthetic and fluorescence properties of 25 families were studied by means of principal component analysis and membership function method.By Comparing the selected 3-year-old with 4-year-old Reaumuria soongorica drought resistance family,to show the the cause of the change and whether it is still excellent drought resistance families and whether there are significant interannual changes between different indicators related to the drought resistance.The purpose of the experiment is to screen out the excellent drought-resistant families that can be stably inherited,guide the selection of provenances and provide the theoretical basis and excellent breeding material for drought-resistant Reaumuria soongorica cultivars in arid desertification area.The test results are as follows:1)Apparent quantum efficiency（AQY）,dark respiration rate（Rd）,light compensation point（LCP）,light saturation point（LSP）,maximum net photosynthetic rate(Pn_max),optimum photochemical efficiency of light systemⅡ（F_v/F_m）,Light system II potential activity（F_v/F0）,photochemical quenching coefficient（q P）,non-photochemical quenching coefficient（q N）,light systemⅡ actual photochemical quantum efficiency Y（Ⅱ）,chlorophyll（a+b）（Chl a+b）,Chlorophyll a/b（Chl a/b）,soluble sugar（SS）,soluble protein（SP）and proline（Pro）were significantly different among families（p <0.01）.2)In the selection of the three-year-old families,the drought-resistance sorti ng was carried out by calculating the comprehensive score of different families under the three principal components.According to the 30% enrollment rate,t he top 8 families were HSW-1>ZZG2-1>XKK-4>LZ-1> ZZG2-3>XGG-3>ZZG1-1>HSZ-3 family.Through the membership function method,eight drought-resis tant families were screened out according to the selection rate of 30%.Droughtresistance from strong to weak followed by LZ-1>HSW-1>XKK-4>ZZG2-1>X GG-3>ZZG2-3> ZYGZ-1>SD-3 family,the families of HSW-1,XKK-4,ZZG2-1,L Z-1,XGG-3 and ZZG2-3 were selected by both membership function method an d principal component analysis.The coincidence rate is 75% and they were the section of excellent drought resistance families.3)In the selection of four-year-old families,the drought-resistance sorting was carried out by calculating the comprehensive score of different families under three principal components.According to the 30% enrollment rate,the top 8 families were XKK-4>HSW-1>ZZG2-1> XGG-3>LZ-1>ZZG1-1>ZZG2-3>HSZ-3 family,the average membership function values were sorted by the membership function method according to the inclusion rate of 30%,drought resistance from strong to weak followed by XKK-4>ZZG2-1>HSW-1>XGG-3>LZ-1>ZZG1-1> ZZG2-3>SD-3family.The families of XKK-4、ZZG2-1、HSW-1、XGG-3、LZ-1、ZZG1-1、ZZG2-3were selected by both membership function method and principal component analysis.With any of those two methods can evaluate the drought resistance of Reaumuria soongorica and the selected families are the drought resistance families.4)Both principal component analysis and membership function method can screen out the families with strong drought resistance,and the two methods showed that the coincidence rate of drought resistance selection is more than 75%,and the selected three-year-old Reaumuria soongorica drought resistance families have also performed well in the selection of four-year families,they are XKK-4,ZZG2-1,HSW-1,XGG-3,LZ-1 and ZZG2-3,and the interannual changes in indicators are not obvious.The interannual variability of the index is not very different.The early selection of any two years can be used as the basis for predicting the drought resistance in the future.The selected families can be used as excellent varieties of drought resistance.