[目的]对91份荔枝(Litchi chinensis Sonn.)种质进行抗寒性综合评价,筛选相对抗寒性强的荔枝种质,为荔枝耐寒育种和各地区荔枝引种提供理论依据.[方法]分别在自然低温前和自然低温后对91份荔枝种质进行采样,测定PS Ⅱ最大光化学量子产量(Fv/Fm)、相对含水量(relative water content,RWC)、相对电导率(relative electrical conductivi-ty,REC)、丙二醛(malondialdehyde,MDA)和脯氨酸(proline,Pro)含量等5个指标,利用隶属函数分析和主成分分析对各项生理生化指标进行综合评价,最后通过灰度关联计算和聚类分析将荔枝种质抗寒性进行排序分类.[结果](1)低温对Fv/Fm、RWC、REC、MDA和Pro含量有显著影响,这5个指标是评价荔枝种质抗寒性较理想的生理指标.(2)将91份荔枝种质分为高度冷敏感(Ⅰ)、冷敏感(Ⅱ)、中度耐冷性(Ⅲ)、耐冷性(Ⅳ)和高度耐冷性(Ⅴ),共5类.[结论]依据荔枝种质综合评价结果,筛选出大锦钟、陈紫和紫娘喜为相对抗寒性强的荔枝种质,可将其作为后续耐寒育种的种质资源,与具有其他优质性状的荔枝种质结合,获得抗寒性强的优质荔枝种质资源.
Comprehensive evaluation of cold tolerance in litchi germplasm resources
[Objective]In recent years,extreme low-temperature occurred frequently in winter,affect-ing the growth and yield of litchi in the following year.Therefore,low temperature is one of the main factors limiting the yield of litchi.Screening chilling-resistant litchi germplasm and breeding low-tem-perature-tolerant varieties is the most effective way to solve this problem.Litchi germplasm resources are important for litchi breeding,scientific research and production.The research on chilling-resistant germplasm resources of litchi started late,and there has been no report about comprehensive cold-resis-tant evaluation on existing litchi germplasm resources.Litchi is a subtropical evergreen fruit tree and has some cold-resistant resources.Most of the cold-resistant resources may remain undiscovered due to few related studies.In this study,91 litchi varieties were comprehensively evaluated for cold resistance.The aim was to screen out litchi germplasm with relatively strong cold resistance,which is important for low-temperature breeding and introduction of litchi in various regions.[Methods]In this study,we selected and numbered litchi varieties with uniform growth status and monitored leaves.At the same time,shoot tips were labeled with hanging tags in the four sides of the canopy.Varietal information was counted on 91 litchi varieties,and five physiological and biochemical indexes were measured before and after low temperature treatments i.e.the maximum photochemical quantum yield of PSⅡ(Fv/Fm),relative water content(RWC),relative electrical conductivity(REC),malondialdehyde(MDA)and pro-line(proline,Pro).A comprehensive evaluation of these five physiological and biochemical indicators were performed through affiliation function analysis and principal component analysis,and comprehen-sive evaluation value(D-value)related to cold tolerance was obtained.Then,the cold resistance of li-tchi germplasm resources was classified through gray-scale correlation calculation and cluster analysis,and finally the cold resistance classification registration was obtained.[Results]Fv/Fm and RWC showed a decreasing trend under low temperatures.In contrast,the REC,MDA and Pro showed an in-creasing trend,suggesting that litchi trees were affected by the chilling stress in the cold winter.Xuehu-aizi litchi trees had the lowest Fv/Fm and the highest REC after low temperature,and were more suscep-tible to damage caused by low temperature.Among the tested litchi varieties,the average value of Fv/Fm was 0.12,and the coefficient of variation was 19.01 after low temperatures.The average value of REC was 14.77％,and coefficient of variation was 40.85 after low temperatures.The average value of RWC remained around 55％before low temperature,and decreased by 13％after low temperature,while the average value of MDA content was 35.02 μmol·mg-1 before low temperature,and increased to 46.39 μmol·mg-1 after low temperature.The average value of Pro content was 404.40 μg·g-1 after low temperature,and increased by nearly 10 times compared to that before low temperature.Hence,low temperature significantly affected Fv/Fm,RWC,REC,MDA and Pro,indicating that these five indexes are desirable physiological indexes for evaluating the cold resistance of litchi varieties.Through system-atic clustering analysis,a total of 91 litchi varieties were evaluated and graded for cold resistance.The cold resistance levels of litchi germplasm were categorized into 5 levels,including highly cold sensitive(Ⅰ),cold sensitive(Ⅱ),moderately cold tolerant(Ⅲ),cold tolerant(Ⅳ),and highly cold tolerant(Ⅴ)levels.The highly cold-sensitive varieties accounted for 7.69％of the total varieties,including Jinxian-guo,Xiafanzhi,Lanzhu,Da zao,Shangshuhuai,Xijiaozi,and Wuyejiu.The second class was cold-sensi-tive varieties,which accounted for 10.99％of the total,including Guanyinlv,Shuidong,Xuehuaizi,Sanyuehong,Salathiel,Kwai May Pink,Heifeihong,Lingfengnuo,Niannianhong No.1 and Shiyueli.The third class was moderately cold-tolerant ones,which accounted for 25.27％of the total.The fourth class was cold-tolerant germplasm,which accounted for 43.96％of the total.The fifth class was highly cold-tolerant germplasm,which accounted for 12.09％of the total,including Ziniangxi,Guilin,Jin-zhong,Jide,Dongliu No.1,Zhuangyuanhong,Dahongpao,Wuye,Songjiaxiang,Chenziand Dajin-zhong.Among the varieties tested,most fell into the category of cold tolerance(Ⅳ),with relatively few in the categories of high cold sensitivity(Ⅰ)and high cold tolerance(V),indicating that the cold resis-tance in litchi germplasm is highly concentrated.[Conclusion]The comprehensive evaluation of litchi varieties was carried out and it was concluded that Ziniangxi,Guilin,Jinzhong,Jidi,Dongliu No.1,Zhuangyuanhong,Dahongpao,Wuye,Songjiaxiang,Chenzi and Dajinzhong belong to the extreme cold tolerant germplasm and have outstanding cold resistance.These varieties can be used as germplasm re-sources for subsequent low temperature breeding.
LitchiNatural low temperaturePhysiological and biochemical indexesComprehensive evaluation
万方数据
维普
