甘薯与海边近缘野生种(厚藤)杂交亲和性测试和分析

Analysis and Test of the Hybridization Compatibility Between Sweet Potato and Its Wild Relative(Ipomoea pescaprae)at the Seaside

为探讨常规杂交培育耐盐甘薯品种的技术,利用海边滩涂近缘野生种厚藤(Ipomoea pescaprae)耐盐的特异性,将其与14个甘薯品种杂交。先是通过嫁接诱导开花,接着经配对杂交组合授粉,观察花粉萌发状况,分析其亲和性。结果显示:甘薯与海边近缘野生种杂交,有些品种可见花粉萌发,具有一定的亲和性,正交亲和的多,反交亲和的少,但多数品种表现为不亲和。海边近缘野生种无明显的甘薯亲和杂交群别属性。甘薯与海边近缘野生种杂交花粉萌发中,花粉管可分为5个类型,表明不同品种亲和性有差异。根据萌发花粉管的不同,计算出亲和指数,其中,广薯79×海边近缘野生种综合亲和指数最高,达中等亲和;5个组合弱,3个组合极弱,没有强或极强组合。亲和组合中,不同时期亲和性强弱亦有差异,亲和指数曲线图出现明显峰值,分别出现在11月份上中旬和次年4月的下旬,但不同的组合或有一定的差异,有的偏强,有的偏弱。亲和指数相对较高的组合中,杂交授粉挂果测试结果表明,亲和指数越低,越容易掉果,掉果率高;亲和指数最高品种,掉果率低,挂果率高,差异明显。因此,测定亲和性,并估算亲和指数,筛选强亲和组合,对指导厚藤和甘薯品种配组杂交具有一定意义。

In order to evolve salt tolerant sweet potato varieties by conventional hybridization through the specificity of their seaside wild relative(Ipomoea pescaprae),the compatibility of crossing between 14 sweet potatos and its seaside wild relative was tested and analyzed.The seaside wild relative and the varieties of sweet potato were grafted onto the rootstocks of a wild relative Ipomoea carnea subsp.fistulosa to induce flowering for crossing.After cross pollination by pairing combinations,pollen germination was observed to analyze the compatibility of the cross combinations.Some sweet potato varieties were observed to have pollen germination when crossed with the seaside wild relative,showing certain compatibility.More positive cross combinations and fewer negative cross combinations showed compatibility but most of the sweet potato varieties presented incompatibility.The seaside wild relative of sweet potato failed to generate obvious cross-compatibility groups when crossed with sweet potato varieties.The pollen tubes can be divided into five types in pollen germination from the crosses between sweet potato and its seaside wild relative,which indicates that the compatibility of different sweet potato varieties with their seaside wild relative varies.The compatibility index is calculated based on germination pollen tubes of various cross combinations.Among the cross combinations the cross combination between Guangshu 79 and the seaside wild relative is highest in comprehensive compatibility index,which is moderately compatible;5 cross combinations are weak,and 3 combinations are very weak in compatibility;no cross combinations are high or very high in compatibility.In the cross compatibility combinations the compatibility is different at different stages.The peak value of the compatibility index curve appeared in the early and middle November and late April,respectively,but the peak value might vary in the cross combinations,slightly higher in some cross combinations and slightly lower in the others.In the cross combinations with relatively high compatibility index,the observation of cross pollination and fruit bearing showed that the cross combinations with lower compatibility index are vulnerable to fruit drop and have a higher rate of fruit drop,and that those with the highest compatibility index have lower fruit drop rate and higher fruitsetting rate,with obvious difference between the cross combinations with lower and the highest compatibility indexes.Therefore,determination of compatibility,estimation of compatibility index and selection of cross combinations with high compatibility have a certain practical role in guiding the cross between the seaside wild relative(I.pescaprae)and sweet potato varieties.