甜菊不同杂交组合结实率及其F1代萌发和生长及对NaCl耐性的比较

以甜菊(Stevia rebaudiana Bertoni)的耐盐性较强品种‘中山3号’和‘守田2号’及R-A高含量品种‘中山4号’和‘守田3号’为亲本配置7个杂交组合并获得杂交种子,对种子结实率和发芽率及F1代幼苗的存活率进行统计分析,在此基础上采用砂培和水培方法比较了亲本及F1代扦插苗对NaCl胁迫的耐性.结果表明:品种间杂交组合的结实率均显著高于同系列品种间杂交及自交组合,其中‘守田2号’ב中山3号’杂交组合的结实率最高,为74.9％；7个杂交组合F1代的种子发芽率为63.8％ ～ 89.0％,差异明显；‘守田2号’ב中山4号’杂交组合F1代幼苗存活率相对较低(79.80％),其他杂交组合F1代幼苗存活率均在93％以上.砂培条件下,用100 mmol·L-1NaCl胁迫7d,各杂交组合F1代扦插苗的存活率差异不显著；随NaCl胁迫时间的延长各杂交组合F1代扦插苗的存活率均明显下降；胁迫28 d,‘守田2号’ב守田 3号’杂交组合以及‘中山3号’自交组合F1代扦插苗的存活率显著高于其他杂交组合.水培条件下,用100、150、200和250 mmol·L-1 NaCl胁迫14 d,‘守田2号’ב中山3号’、‘中山3号’ב守田2号’和‘中山3号’ב守田3号’3个杂交组合F1代扦插苗的存活率均显著高于其耐盐亲本及其他杂交组合.研究结果说明:通过杂交提高甜菊耐盐能力是可行的,而亲本的耐盐能力及亲本配置对杂交后代目标性状有较大影响；‘中山3号’ב守田2号’、‘守田2号’ב中山3号’和‘中山3号’ב守田3号’是耐盐性较强的甜菊优良杂交组合.

Comparisons of setting rate of different cross combinations of Stevia rebaudiana and germination,growth and NaCl resistance of their F1 hybrids

Taking two salt tolerance cultivars(’Zhongshan No.3’ and ’Shoutian No.2’) and two high R-A content cultivars(’Zhongshan No.4’ and ’Shoutian No.3’) of Stevia rebaudiana Bertoni as parents,seven cross combinations were combined and hybrid seeds were obtained.And setting rate of seven cross combinations and seed germination rate and seedling survival rate of F1 hybrids were statistically analyzed,and on the basis,resistance to NaCl stress of cutting seedlings of F1 hybrids was compared by sand culture and hydroponics methods.The results show that setting rate of cross combinations among cultivars is significantly higher than that between same line cultivars and self-cross combinations,in which,that of cross combination ’Shoutian No.2’ ×’Zhongshan No.3’ is the highest with a setting rate of 74.9%.There are obvious differences in seed germination rate of F1 hybrids among seven cross combinations with the rate of 63.8%-89.0%.Seedling survival rate of F1 hybrids of cross combination ’Shoutian No.2’ ×’Zhongshan No.4’ is relative low(79.80%),while that of other cross combinations is over 93%.Under sand culture condition,with 100 mmol·L-1 NaCl stressing for 7 d,survival rate of cutting seedlings of F1 hybrids among seven cross combinations has no significant difference,but that obviously decreases with prolonging of NaCl stress time.And NaCl stressing for 28 d,survival rate of cutting seedlings of F1 hybrids of cross combination ’Shoutian No.2’ ×’Shoutian No.3’and self-cross combination ’Zhongshan No.3’is significantly higher than that of other cross combinations.Under hydroponics condition,with 100,150,200 and 250 mmol·L-1 NaCl stressing for 14 d,survival rate of cutting seedlings of F1 hybrids of cross combinations ’Shoutian No.2’ ×’Zhongshan No.3’,’Zhongshan No.3’×’Shoutian No.2’ and ’Zhongshan No.3’× ’Shoutian No.3’ is higher than that of salt tolerance parents and other cross combinations.It is suggested that improving salt resistance of S.rebaudiana by cross breeding is feasible,and parental salt tolerance and parental combinations have great effects on target traits of hybrids.And ’Zhongshan No.3’×’Shoutian No.2’,’Shoutian No.2’ ×’Zhongshan No.3’ and ’Zhongshan No.3’× ’Shoutian No.3’are better cross combinations with stronger salt resistance.