高粱亲本系萌发期抗旱性鉴定

根据高粱亲本系萌发期对干旱胁迫的响应,筛选出抗旱性鉴定指标和抗旱性强的种质,为高粱抗旱基因挖掘与种质创新奠定基础。以15份保持系、18份恢复系和8份杂交种为材料,采用人工气候箱内培养皿培养,以水势为-0.3MPa的PEG-6000水溶液模拟干旱胁迫环境,蒸馏水处理为CK。测定发芽率、发芽势、芽长、根长、芽干重、根干重、剩余物质干重和萌发抗旱指数等8个性状。通过隶属函数法和聚类分析对参试材料进行抗旱性综合评价,并进行因子分析。利用隶属函数法对参试材料抗旱性排序表明,不同参试材料间表现出较大差异。高粱保持系、恢复系隶属函数值显著低于杂交种,保持系与恢复系隶属函数值差异不显著。聚类分析把参试材料按抗旱性强弱分为5类,L116等2份材料为抗旱类型,Ms18B等18份材料为较抗旱类型,Ms19B等9份材料为抗旱中间类型,L5172等8份材料为干旱较敏感类型,2055B等4份材料为干旱敏感类型。结果表明,萌发抗旱指数、根长和剩余物质干重分别在萌发因子、根部生长因子和生物量转化因子中的负荷量最大。对应水势为-0.3 MPa的PEG-6000浓度能够作为高粱亲本系萌发期抗旱性鉴定的适宜浓度。保持系、恢复系抗旱能力显著低于杂交种,保持系、恢复系抗旱能力差异不显著。筛选出萌发期抗旱性强亲本材料,分别为恢复系L116和保持系Ms27B。萌发抗旱指数、根长、剩余物质干重可作为高粱亲本系萌发期抗旱性鉴定的适宜指标。

Identification of the drought resistance of sorghum parental lines at germination stage

The objectives of this study were to explore the response of different sorghum parental lines to drought stress,and screen a set of suitable indexes for identifying drought resistance in parental lines with high drought resistance.A total of 41 sorghum materials including 15 B-lines,18 R-lines,and 8 hybrids germinated in Petri dishes in artificial climate chamber were taken as study materials.PEG-6000(-0.3 MPa) was used to simulate the typical drought stress environment with distilled water as control.Eight parameters including germination rate,germination potential,bud length,root length,bud dry weight,root dry weight,remaining material dry weight,and germination drought resistance index were measured.The results showed that the average subordinate function values of B-lines and R-lines were significantly lower than that of hybrids and no significantly differences existed between B-lines and R-lines.All materials were clustered into five groups:Two materials were resistant to drought,e.g.L116;Eighteen materials were relative resistance to drought,e.g.Ms18B;Nine materials had medium resistance,e.g.Ms19B;Eight materials were relatively sensitive to drought,e.g.L5172;Four materials were sensitive to drought,e.g.2055B.The germination drought resistance index,root length and the remaining materials dry weight had the largest loading on germination factor,root growing factor,and biomass transformation factor,respectively.PEG-6000 with -0.3 MPa water potential was suitable for drought resistance screening of sorghum parental lines.The ability of drought resistance of sorghum parental lines was significantly lower than that of hybrids,which was not significantly different between B-lines and R-lines.B-line L116 and R-line Ms27B had high drought resistance.In conclusion,the germination drought resistance index,root length,remaining material dry weight were recommended as the suitable indexes for identifying drought resistance of sorghum parental lines at germination.