Studies On The Differences Of Drought Resistance And Saline-alkali Resistance And Adaptability Of Different Maize Varieties(Lines)

Drought and saline-alkali are major abiotic stresses often having seriously double impacts on crop yield.Selection and identification of maize lines with drought resistance and saline-alkali tolerance is the base for breeding new varieties survive drought and saline-alkali conditions.The purpose of this study was to identify and screen maize germplasm with resistance to drought and tolerance to saline-alkali,and to explore the differences underlying the adaptations of maize materials to drought and saline-alkali stresses,providing scientific theoretical basis for selection of drought-resistant and saline-alkali-tolerant maize varieties.In this work,maize materials with different drought-resistance and salinity-tolerance were chosen.Two-yield field experiments from 2016 to 2017 were conducted in Wangtuan town,Tongxin county(located in Ningxia Central Arid Belt)and Gaozhuang town,Pingluo county,Ningxia.The differences underlying the adaptations of 36 maize materials to drought and saline-alkali stresses were studied by measured physiological and agronomic characters using the principal component analysis and the membership function.The objectives of this study are to select maize varieties/lines with drought-resistance andsaline-alkali-tolerance and to reveal the differences in adaptations to drought and saline-alkali stresses.The main results are as follows:1.Based on measurement on the agronomic traits and photosynthetic characters,36 maize varieties/lines grown in rainfed condition in Ningxia Tongxin(with rainfall 146.80 mm during whole growth period)and in saline-alkali condition in Ningxia Gaozhuang county(with total soluble salinity content 5.756 g/kg and pH 8.71)were found to be dif-fered in drought-resistance and saline-alkali-tolerance.16 drought-resistant materials,13 salinity-tolerant materials,and 4 materials with both drought-resistance and saline-alkaline-resistance were selected.2.There was a significant difference in drought-resistance for different maize varieties/lines in different growth periods.5 maize varieties/lines with large variation in drought-resistance were adopted and planted in three water conditions with whole growth period irrigation being 262 mm(A1),501 mm(A2)and 623 mm(A3).Physiological and agronomic traits were determined and analyzed.The ranking of whole growth period drought-resistance based on principal component analysis and comprehensive evaluation was H242/1523>Guqingchu No.l>North 21/1522>H14/A18>H14/1528.The comprehensive evaluation value(D value)of H242/1523 at jointing stage,grain-filling stage and mature stage were 0.847,0.793 and 0.823,respectively,showing strong drought resistance.At the big flare period,North 21/1522 exhibited the strongest drought resistance,with a D value of 0.738.3.There was a significant difference in saline-alkali-tolerance for different maize varieties/lines in different growth periods.5 maize varieties/lines with large variation in saline-alkali-tolerance were adopted and planted in saline-alkali land with total soluble salinity content and pH values being 3.228 g/kg and 9.38(T1),2.203 g/kg and 9.12(T2)and 1.880 g/kg and 9.01(T3),respectively.The ranking of whole growth period saline-alkali-tolerance based on principal component analysis and comprehensive evaluation was H242/1523>Guiqingchu No.1 ＞ H14/1528 ＞ H14/A18 ＞ North 21/1522.The comprehensive evaluation value(D value)of H242/1523 at jointing stage,big flare stage and mature stage were 0.852,0.845 and 0.828,respectively,showing strong tolerance to salinity and alkalinity.At the grain-filling period,Guiqingchu No.l exhibited the strongest saline-alkali tolerance,with a D value of 0.690.4.There is an association between drought-resistance and saline-alkali-tolerance.Through two years of comparative study on physiological and agronomic traits of drought-resistance and saline-alkali-tolerance.Strong drought-resistance and saline-alkali-tolerance were simultaneously found for 133-2/1528,Ning3-2/1528,H242/1523 and H398/1523.While drought-resistance lines A28/1522 and 5178-1/1528 were susceptible to saline-alkali stress.5.Discrepant adaptability to drought and saline-alkali stresses was found in different maize varieties/lines by a series studies on osmotic regulation,selective absorption of ions,photosynthetic physiology and agronomic characters.A28-1522 and 5178-1/1528 have strong drought-resistance and could be grown in area like Ningxia Central Belt with annual rainfall of 300 mm.133-2/1528,Ning3-1/1528 and Ning3-2/1528 were endowed with strong tolerance to salinity and alkalinity and could be planted in a saline-alkali land with total soluble salinity content and pH of 5.756 g/kg and 8.71.