Difference Analysis Of Photosynthetic Characteristics And Tuber Quality Of Different Varieties Of Chinese Yam (Dioscorea Opposita Thunb.)

Yam(Dioscorea opposita Thunb.)is an annual or perennial herbaceous plant in the family Dioscoreaceae,with excellent medicinal and edible properties.In recent years,with the expansion of yam planting area in Inner Mongolia,the existing yam varieties cannot meet the market requirements for high-quality yam.Therefore,it is of great significance to introduce high-quality yam for the production of Inner Mongolia Yam.MSY,XM,SB,TG,LC,HP,XBZ and BY of yam were used as experimental materials,and introduced them to the planting resource garden of Inner Mongolia Agricultural University.Under the same growing conditions,we correlated the growth,photosynthetic characteristics,tuber quality and yield of these varieties and evaluated their adaptability.。From these varieties,we selected yam varieties with excellent overall characteristics that are suitable for further promotion in the Hohhot region of Inner Mongolia.This study provides a theoretical basis for the evaluation and screening of high-quality yam cultivars in the central and western regions of Inner Mongolia.The main conclusions are as follows:(1)Morphological investigation showed that the growth potential of MSY,SB,LC and BY was significantly stronger than TG,XM,HP and XBZ.The leaf shape index of BY is the largest and TG is the smallest.The stem rotation of all varieties was dextral,without flank,and all flowering in this area.The tuber diameter,length and fresh weight of BY and LC yam increased the fastest from the middle stage of tuber expansion to the peak stage.(2)The nutritional quality of tubers during growth period showed that fresh weight of tubers was negatively correlated with total soluble sugar content,and positively correlated with other quality indexes.Fresh weight of tubers was significantly negatively correlated with total soluble sugar content of SB,positively correlated with sucrose and amino acid content of MSY,and positively correlated with starch and reducing sugar content of LC.The results of tuber quality determination at harvest stage showed that the quality of BY,SB,XBZ and MSY was better.The content of BY starch was the highest,which was 86.17%.The reducing sugar content of XBZ was the highest,which was 3.9%.The variety with the highest sucrose content was also XBZ,which was 0.44mg/L.The highest soluble total sugar content was found in XM,followed by BY,67.63%and62.51%respectively.SB,BY and MSY soluble protein and amino acid were relatively high.(3)The results of the photosynthetic characteristics of different yam species showed that the photosynthetic capacity of BY,MSY,SB and LC was stronger;Pn was positively correlated with stomatal conductance(Gs)and transpiration rate(Tr);Pn was negatively correlated with intercellular carbon dioxide concentration(Ci);Pn was found to be positively correlated with the accumulation of nutritional quality and yield of tubers;Pn was positively correlated with tuber starch,sucrose and reducing sugar content,and reached a highly significant positive correlation with hemp yam starch and reducing sugar.Pn was positively correlated with soluble protein and amino acid content.Combined with the correlation analysis between fresh weight and quality of tuber,it can be concluded that Pn can promote the formation of yam yield.(4)It was found that the yield per plant of BY was the highest,and the yield per plant of TG was the lowest.The highest drying rate is TG,the lowest is SB;It was found that the yield of BY was the highest,which was 2391.68kg/666.67m~2,which was 1.02times,1.09 times and 1.16 times of SB,MSY and LC,respectively.So in terms of yield,BY,MSY and LC were suitable for local cultivation.The rate of SB deformity was the highest(16.43%),and the commodity rate of BY,MSY and XM was higher.MSY,SB,LC and BY tuber are cylindrical,which is better than TG MSY in morphology.Through investigation on the characteristics of Chinese yam head,only Chinese Yam head is short and thick,which is conducive to maintaining the integrity of Chinese yam in the process of harvesting and preservation.According to the comprehensive evaluation by clustering heat map analysis and entropy TOPSIS ranking,BY,LC and MSY are suitable for the local growing environment,and can be popularized and cultivated as high-yield and high-quality varieties in Hohhot.