不同倍性苹果种质花器官表型性状多样性研究

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Abstract：A total of 48 apple germplasm accessions，including diploid，triploid and tetraploid，were selected as materials.Fourteen phenotypic traits of flower organs were observed and data were collcted.The distribution frequencyand coeficient of variation of diferent phenotypic traits were calculated and analyzed.The number and morphological characteristics of polln grains were observed under an optical microscope.The purose of this study was to provide references for the evaluation，identification and utilization of apple polyploid germplasm resources.The results showed that：（1） The phenotypic diversity of flower organs of different ploidies in apple was rich.The characters of pink flower buds，yelow anthers，adjacent petals in relative positions，ovate petals，and pubescence at the base of the style were the most common，accounting for 60.4% ， 100% ， 54.2% ， 79.2% and 97.9% of the descriptors' distribution frequency，respectively.（2）Traits such as flower number per inflorescence，stamen number，petal length and width，corolla diameter，and stigma number show relatively low variation among diferent varieties （lines）within the same ploidy level，with coefficients of variationbelow 20.0% .However，triploid and tetraploid apples exhibit significantly larger average values for corolla diameter，petal length，and petal width compared to diploid apples.Moreover，the average corolla diameter of two tetraploid varieties exceeds that oftriploid apples.These findings suggest that an enlarged corolla diameter can serve as a useful auxiliary marker for identifying polyploid variations within the same apple variety （line）.（3）The proportions of diferent-shaped pollen grains varied among different ploidies.The proportions of larger pollen grains，round pollen grains and square pollen grains were significantly higher in polyploids than in diploids.This suggested that a higher proportion of round and square polen grains can be used as an effective auxiliary selection trait for identifying apple polyploid variations.The ratio of the number of triangular polen grains to the sum of the numbers of round and square pollen grains was significantly diferent between diploids and tetraploids and the ratio of 1.6 could be used as a critical value for identifying ploidy.

Key words： apple; germplasm resources ; flower phenotypic traits ; polyploid; pollen morphology

苹果是蔷薇科（Rosaceae）苹果亚科（Maloideae）苹果属（Malus）的多年生落叶乔木，广泛分布于北温带地区，包括亚洲、欧洲和北美洲。（剩余15465字）