观赏海棠品种间的杂交亲和性研究和亲本选择

Study on the Cross Compatibility and Parent Selection among Ornamental Crabapple Cultivars

为筛选出优质亲本及杂交组合,确定最佳授粉时期,探究观赏海棠品种间的杂交亲和性,为观赏海棠的新品种培育提供参考,该研究以15个性状互补的海棠品种为供试材料,用离体培养法测定花粉活力、悬液法测定花粉含量并对其雄性育性进行评价;联苯胺-过氧化氢法测定其不同开花时期的柱头可授性;荧光显微观察法观察授粉后花粉管的生长及受精情况;人工控制授粉法研究5个杂交组合的坐果动态变化情况。结果显示,(1)根据花粉活力可将15个海棠品种的雄性育性分为不育型、较低型、中等型、优质型4类,其中‘印第安之夏’、‘冬红’等6个品种为优质父本。(2)海棠从开花前1 d至第6天的柱头可授性呈现“弱—强—弱”的变化规律,开花第3天时的柱头可授性最强。(3)授粉后4~8 h花粉开始萌发,48~96 h完成受精。(4)花粉育性和柱头可授性与杂交坐果率、种子饱满率间均存在显著的正相关性。授粉后2个月内是落果集中期,此后至果实成熟坐果率基本趋于稳定。‘冬红’ב印第安之夏’、‘草莓果冻’ב印第安之夏’为高坐果率杂交组合。研究表明,海棠雌雄蕊存在发育不同步现象,选择育性优质的亲本是杂交取得成功的关键,而受精后障碍是本研究中海棠杂交不亲和的主要原因。

Selecting excellent parents and cross combinations,determining the optimal pollination period and exploring the cross compatibility among ornamental crabapple cultivars are valuable to provide references for the breeding of new cultivars.In this study,15 crabapple cultivars with different ornamental characteristics were selected,the pollen viability and anther pollen quantity were determined by in vitro culture method and suspension method,respectively.Then their male fertility was evaluated.The stigma receptivity at different days was determined by benzidine-hydrogen peroxide method,the growth and fertilization of pollen tubes after pollination were observed by fluorescence microscopy,and the fruit setting of 5 cross combinations were studied by artificial controlled pollination.The results were as follows,(1)the male fertility of 15 cultivars could be divided into 4 types:Male sterile,low fertility,medium fertility and high fertility according to the pollen viability.Among them,6 cultivars such as‘Indian Summer’and‘Winter Red’were high quality male parents.(2)The stigma receptivity showed a law of“weak-strong-weak”from 1 day before flowering to 6th day after flowering,and the 3rd day was the optimal pollination period.(3)The pollen began to germinate at 4-8 h and fertilized at 48-96 h after pollination.(4)There was a significant positive correlation between pollen fertility,stigma receptivity and fruit setting rate and seed plumpness rate.Besides,the peak period of fruit drop was within 2 months after pollination,then the fruit setting rate tended to be stable.‘Winter Red’בIndian Summer’and‘Strawberry Jelly’בIndian Summer’were high fruiting rate cross combinations.These results show that ornamental crabapple is dichogamous,parents with high fertility are the key to the success of cross,and the main reason for the incompatibility of crabapple is post-fertilization disorder in this study.