Study On Yield Characteristics And Physiological Response Of Different Types Of Chenopodium Quinoa Willd. Under Soda Saline-alkali Condition

Quinoa（Chenopodium quinoa Willd.）is rich in nutritions and exhibits strong stress resistance.It is suitable for industrial promotion due to widely adaptability to different planting regions.In recent years,land salinization has become one of the most widespread abiotic stress factors affecting agricultural and animal husbandry productivity and limiting crop yield.The high salinization degree of soda soil in the western Jilin Province,and the serious grassland degradation have brought typical ecological fragile problems in China.In this content,planting saline-alkali-tolerant crop（eg.quinoa）can improve the utilization rate of saline-alkali soil,and promote the development of related industries,thereby bringing higher ecological and economic benefits.At present,the adaptability of different types of quinoa to soda saline-alkali soil has not arouse attentions,and the physiological response mechanism of different types of quinoa under saline-alkali condition is still need to be more tested.In this study,four grain types of quinoa（black,white,red and gray grain types）were selected as research to test the key indicators such as plant characters,grain yield,photosynthetic parameters,soluble sugar content,carbon and nitrogen element and isotope composition,chlorophyll content and cation content in a completely randomized block experimental design.The aim is to reveal the physiological response mechanism and adaptation strategies of each type of quinoa to soda saline-alkali soil,and to evaluate the differences of salt-alkali tolerance.Thereby screening out the quinoa type with strong saline-alkali tolerance and high yield.Finally to improve the ecological environment of this area by using quinoa plating,and provide a reference for the promotion and planting quinoa in soda saline-alkali land.The main results of this experiment were as follows:（1）The grain yield of quinoa was significantly different in different years under the influence of climate,and the interaction between types and years.Black and gray grain quinoa exhibited higher grain yield and indicated tolerant saline-alkali stress.During two years of the experiment,the yields of black grain quinoa were 1695.09 kg/hm²and 1096.74 kg/hm²,and the yields of gray grain quinoa were 1430.54 kg/hm²and 1127.75 kg/hm²,respectively in the year 2020 and 2021.The white grain quinoa was not tolerant to salinity,which had the lowest yield of 1190.00 kg/hm²and 895.68 kg/hm²,respectively in the two years.The yields of red grain quinoa were 1039.00 kg/hm²and 1339.29 kg/hm²,respectively.The grain yields of black,white and gray grain quinoa decreased in different degrees in the cool climate,while red grain quinoa was suitable to survive in this climate and could achieve higher yield performance.（2）The analysis of the botanical characteristics of different types of quinoa showed that black and gray grain quinoa were tall,with thick stems.They had many branches,which could improve the efficiency of light utilization and promote the growth of stems and leaves.At maturity,the grains were plump,the 1000-grain weight was larger,and the grain yield was higher.The plant characters of red grain quinoa were easily affected by the climate environment.In the hot and humid climate,the growth was poor,the biomass of stems and leaves was low.However,it was suitable for survival in the cool climate,the number of spikelets and grains per plant were high,and the yield performance was good.The white grain quinoa was not tolerant to salinity,with short plant hight and few branches,resulting in lower grain yield.（3）The analysis of the water state of different types of quinoa showed that black and gray grain quinoa had high stomatal conductance,more CO₂entering the leaves.And the water use efficiency was high,it could promote photosynthesis and produce more soluble sugar,which indicated that the salinity was strong.At the same time,the ability to repel¹³CO₂under natural conditions was strong,and the carbon isotope composition(δ¹³C)in the body was relatively low,which indicated that the leaves had strong water-locking ability and strong adaptability.The growth of red grain quinoa was highly dependent on the climate environment.It had a high net photosynthetic rate and was suitable for survival in the cool climate.The net photosynthetic rate and water use efficiency of white grain quinoa were low,which was not conducive to photosynthesis,and was not tolerant to salinity.The results showed thatδ¹³C can be used as an important indicator to measure the ability of plants to tolerate saline-alkali stress and grain yield.（4）The analysis of the nitrogen state of different types of quinoa showed that the nitrogen isotope composition(δ¹⁵N)in stems and leaves of black and gray grain quinoa was lower,which had a certain dilution effect on the nitrogen concentration.In addition,the high chlorophyll content promoted the absorption and utilization of nitrogen,thereby improving the balance of carbon and nitrogen metabolism and the accumulation of nutrients among various tissues,and forming a nitrogen basis for yield improvement.Red grain quinoa could fully absorb and utilize nitrogen in the cold climate,which was beneficial to growth and metabolism activities.Theδ¹⁵N in white grain quinoa was high,and the chlorophyll content was low,so the absorption and utilization of nitrogen was poor,resulting in poor yield performance.（5）The analysis of cation content of different types of quinoa showed that black and gray grain quinoa absorbed and accumulated more Na⁺for effective osmotic regulation to maintain water balance in the body.The high content of K⁺in the body could ensure the normal progress of physiological metabolism.And K⁺/Na⁺was in the best state,which indicated that the salt-alkali tolerance was strong,which was conducive to the survival of plants in adversity.The contents of Na⁺,K⁺and K⁺/Na⁺in the stems and leaves of white and red grain quinoa were low,so they were not suitable for survival in this environment.（6）The strong saline-alkali tolerance of black grain quinoa was mainly affected by nitrogen status.Chlorophyll content and nitrogen concentration in stems were the key factors to determine grain yield and 1000-grain weight,respectively.The poor salt-alkali tolerance of white grain quinoa was mainly caused by the poor ion balance in the body,and K⁺and Na⁺content in stems limited the formation of grain yield and 1000-grain weight,respectively.For red grain quinoa,intercellular CO₂concentration difference and chlorophyll content might be the main factors affecting grain yield.The strong saline-alkali tolerance of gray grain quinoa was mainly affected by water state,andδ¹³C in leaves and transpiration rate were the key factors affecting grain yield and 1000-grain weight,respectively.Principal component analysis showed that the content of cation in plants altered yield formation by affecting nitrogen metabolism processes.Andδ¹³C in stems could change with plant growth,which was the best negative index.To sum up,from the aspects of water state,nitrogen state and ion balance in plants,black and gray grain quinoa showed good botanical characteristics and higher yields.Therefore,they were suitable for popularizing and planting in the soda saline-alkali area in the western Jilin Province.However,the growth status and yield performance of white grain quinoa were poor,and the yield performance and saline-alkali tolerance of red grain quinoa were greatly affected by the external environment.Therefore,they should pay attention to select the environment with good soil moisture and suitable climate in the process of planting in order to obtain higher yield under the mild saline-alkali condition.