Comparative Study On Agronomic Traits And Quality Of Different Yam Varieties

Yam(Dioscorea opposite Thunb.)is a nutritious vegetable for both medicine and food,which has high economic value.In recent years,as the development of society and the changes of the times,yam is more and more popular.Northerm China,especially Shandong,Henan and Hebei provinces,is the major producer of yam in China.With a long history of cultivation in yam,these areas have a great many characteristics varieties of good quality.However,most of these varieties are only planted in the local and surrounding areas,and a plenty of excellent varieties are not widely planted.In this study,11 yam varieties of different origins and types were compared in terms of agronomic traits and quality.It is hoped that it will provide theoretical basis for the classification of yam varieties and the breeding of new yam varieties,as well as for the development of yam industiy and the promotion of excellent yam varieties in Weifang and even the northern China.The main results are as follows:1.Different varieties of yam had different growth vigor.Jipicao,Mi yam,Dahechangyu,Ma yam.Huai yam and Tiegun yam had stronger growth vigor.Changshanximao,Jiaxiangximao yam,Xishizhongzi and Xiaobaizui had medium growth vigor.No.2 Daheyu had weaker growth vigor.2.There were significant differences among different yam varieties.Thi'ough cluster analysis,it could be divided into three categories:Huai yam.Ma yam,Xiaobaizui,Jipicao,Tiegun yam and No.2 Daheyu had stronger disease resistance;Changshanximao,Dahechangyu and jiaxiangximao yam showed moderate disease resistance;Mi yam and Xishizhongzi resistance was weak.3.The average yield of the 11 yam varieties from 2016 to 2018 was 1750.80-4421.10 kg/667 m2.There were significant differences among different yam varieties.The yield of Dahechangyu was the highest(4421.10 kg/667 m2)while that of Tiegun yam was the lowest(1750.80 kg/667 m2).The varieties were sorted from high to low by the yield as follows:Dahechangyu,Mi yam,Ma yam,Huai yam,Changshanximao,No.2 Daheyu,Jiaxiangximao yam,Xiaobaizui,Xishizhongzi.Jipicao and Tiegun yam.4.With the extension of storage time,the browning degree of fresh-cut yams showed an upward trend.The browning index increased rapidly at room temperature,and had reached or approached the maximum by the 120th hour.The growth of browning index could be significantly reduced in a circumstance of low temperature storage,and good quality had been maintained for most yal varieties by the 10th day.Some varieties were suitable for fresh-cut processing,such as Huai yam,Xishizhongzi,Xiaobaizui,Jiaxiangximao yam,Changshanximao and Jipicao;while other ones were unsuitable for fresh-cut processing,such as Dahechangyu,Mi yam and Ma yam.5.The nutrient contents of different varieties of yam tubers were different.The water contents of the 11 yam varieties ranged from 67.8%to 83.9%.The water contents of Dahechangyu,Ma yam and Mi yam were higher,while those of No.2 Daheyu and Xishizhongzi were lower.The starch contents of the 11 yam varieties ranged from 11.6%to 29.2%.The starch contents of Xishizhongzi,Jipicao,No.2 Daheyu and Tiegun yam were higher,while that of Dahechangyu was lower.The protein contents of the 11 yam varieties ranged from 1.71%to 4.09%.The protein contents of Jipicao,Tiegun yam,Xishizhongzi and No.2 Daheyu were higher,while those of Mi yam and Dahechangyu were lower.The total sugar contents of the 11 yam varieties ranged from 0.42%to 1.87%.The total sugar contents of Dahechangyu and Mi yam were higher,while those of Changshanximao and Jipicao were lower.6.A large difference exists in steamed qualities of different yam varieties.The comprehensive score of sensory evaluation of the 11 varieties was between 20.4 and 48.2.The score of Xishizhongzi was the highest,and that of Dahechangyu was the lowest.There were 7 yam varieties with better steamed quality,including Xishizhongzi,Xiaobaizui,Jiaxiangximao yam,Tiegun yam,Jipicao,Changshanximao and No.2 Daheyu,while the other four with worse steamed quality,including Ma yam,Huai yam,Mi yam and Dahechangyu.Based on the comparative study of agronomic traits and quality,and considering the cultivation and production use,it is considered that Dahechangyu,Ma Yam and Mi yam can be used as high-yield varieties for popularization and cultivation;Xishizhongzi,Xiaobaizui,Jiaxiangximao Yam,Changshanximao,Jipicao and Tiegun Yam can be used as high-quality varieties for popularization and cultivation;and Huai Yam and No.2 Daheyu can be used as processing varieties for popularization and cultivation.