甘肃野生草地早熟禾萌发期抗旱性鉴定与评价

Identification and Evaluation of Wild Poa pratensis Varieties from Gansu for Drought Resistance During Germination Stage

采用-0.1,-0.3,-0.5和-0.7 MPa的聚乙二醇6000(PEG-6000)模拟不同程度的干旱胁迫,在萌发期分别处理8份野生草地早熟禾(Poa pratensis)种质和2个商用品种21d,并测定发芽率、发芽势和活力指数等7个鉴定指标,并以其相对值作为评价指标,利用隶属函数法和聚类分析对供试的10份种质材料进行了综合评价和分类,同时,对各鉴定指标在草地早熟禾萌发期抗旱性评价中的作用进行了比较分析。结果表明,用于草地早熟禾萌发期抗旱性研究的适宜PEG-6000浓度为-0.1^-0.3 MPa,种子活力指数和发芽率受干旱胁迫的影响较大,且与抗旱性的关系最为密切,可作为草地早熟禾种质萌发期抗旱性鉴定的重要指标。10份种质材料抗旱性由强到弱依次为:秦州>西和>陇西>安定>渭源>天祝>榆中>MidnightⅡ>清水>Baron;聚类分析可把供试材料按抗旱性强弱分为三类,其中清水和Baron属于干旱敏感种质;安定、渭源和MidnightⅡ等属于中等抗旱种质;秦州、西和和陇西属于抗旱种质,可作为抗旱育种材料。

Different concentrations of PEG-6000 （-0.1, -0.3, -0.5 and-0.7 MPa） was used to simu- late drought stress environment. Germination rate, germination potential, vigor index and other four iden- tification indices of 8 wild Poa pratensis varieties and 2 eultivars were measured under drought stress dur- ing germination stage. According to the relative value of seven identification indices as evaluation indices, drought resistance of Poa pratensis varieties was comprehensively evaluated and classified by the methods of membership function and cluster analysis. Furthermore, the role of each identification indices in evalua- ting drought resistance of different varieties was compared. The results showed that -0. 1 - -0. 3MPa PEG-6000 was the optimum osmotic stress concentration to study drought resistance of Poa pratensis at germination stage. Seed vigor index and germination rate were more susceptible to drought resistance and closer to the comprehensive evaluation value of drought resistance, and it could be used as the most impor- tant indices for identification of drought resistance of Poa pratensis. The drought resistance of all varieties decreased in the order as： Qinzhou, Xihe, Longxi, Anding, Weiyuan, Tianzhu, Yuzhong, Midnight Ⅱ , Qingshui and Baron. The cluster analysis showed that Qingshui and Baron were sensitive to drought stress three varieties had medium drought tolerance, for example Anding, Weyuan and MidnightⅡ; Qinzhou, Xihe and Longxi were the highest drought tolerant, which can be used to breeding new drought tolerant cultivars in the future.