四倍体白掌新品种‘绿萌'的选育

白掌又名白鹤芋,原产于美洲和亚洲的热带地区,为天南星科白鹤芋属多年生草本植物,是重要的观花观叶盆栽植物,当前市场主栽品种基本源于国外,多为人工杂交产生的后代。利用人工诱变技术对植物体细胞染色体组进行加倍的多倍体育种方法已应用于观赏花卉新品种的选育,多倍体植株具有叶片增大、叶色加深、花朵变大、花色艳丽等优良性状,与二倍体比较,目标性状的观赏价值更高。利用化学诱变产生多倍体是目前人工多倍体育种中常用的诱导方法,其具有操作简易、突变率高、专一性强和适用性广等特点。秋水仙素是目前主要采用的多倍体化学诱变剂,其诱导的效果与诱导时间、使用的浓度、处理的植物种类和器官等因素有关。本研究以白掌‘美酒'的组培苗愈伤组织为材料,优化四倍体白掌诱导方法,经秋水仙素浸泡处理后,开展试管苗形态学初筛、田间种植优选及株系比较试验,同时进行染色体计数、气孔大小和基因组大小比较、四倍体白掌新品种选育。结果表明：最佳诱导四倍体白掌的方式为0.10%秋水仙素浸泡处理7 d,其四倍体诱导率最高;选育出的四倍体白掌新品种‘绿萌'在设施大棚种植时自然花期为4—6月,与对照‘美酒'相比,叶片长和宽、叶柄长和直径、叶鞘长、佛焰苞苞片长和宽、花梗长和直径、肉穗花序长和直径、气孔长度和宽度、气孔密度均差异极显著,根尖染色体数为2n=4X=60,是对照（2n=2X=30）的2倍。流式细胞仪测定DNA显示,‘绿萌'基因组大小为10.87 Gb,对照‘美酒'基因组大小为5.73 Gb,鉴定为四倍体白掌新品种。本研究利用人工化学诱变方法选育的四倍体白掌新品种‘绿萌',具有叶片增厚、叶色加深、茎杆变粗、叶柄变粗、花梗变粗、肉穗花序变粗等特点,大大提高了白掌的观赏价值。

Breeding a New Tetraploid Spathiphyllum floribundum ‘Lvmeng' Variety

Spathiphyllum floribundum is an important ornamental foliage and flower plant and is an perennial herb native to the tropics of America and Asia. At present, most of the main varieties in China are from abroad, and the offspring of artificial hybridization. The polyploid breeding method of doubling the chromosome sets of plant somatic cells by artificial mutation technology is often applied to ornamental flowers. The variety of selected polyploid plants showed excellent traits such as leaf enlargement, leaf color deepening, flower enlargement and gorgeous flower color, which could greatly improve the ornamental value of the target traits. Using chemical mutagens to induce polyploids is a common induction method in artificial mutagenesis technology because of its simple operation, high mutation rate, strong specificity and wide applicability. Colchicine is a polyploid chemical mutagen mainly used in polyploid induction at present. The effect of colchicine on inducing polyploidy is related to induction time, concentration, plant species and organs. The callus of S. floribundum Meijiu was used as the material. The induction method of tetraploid was optimized. Morphological screening of seedlings in vitro, field selection and comparison of plants regeneratrd were carried out. Furthermore, the number of chromosomes, stomatal size andgenome size identification were used for breeding and identified new varieties of S. floribundum. The results showed that the best way to induce tetraploid S. floribundum was soaking with 0.10% colchicine for 7 days. The flowering duration of the newly selected ‘Lvmeng' was from April to June when it was planted in the greenhouse. Compared with the control S. floribundum ‘Meijiu', there were significant differences in leaf length, leaf width, petiole length, petiole diameter, leaf sheath length, bracts length, bracts width, bracts stalk length, bracts stalk diameter, spadix length, spadix diameter, stomatal length, stomatal width and stomatal density at the flowering stage. The number of chromosomes was 2n=4X=60, which was twice that of the control 2n=2X=30. Flow cytometry DNA analysis showed that the genome size of ‘Lvmeng' was 10.87 Gb, and that of the control ‘Meijiu' was 5.73 Gb. It was identified as a new tetraploid species of S. floribundum. The new polyploid variety ‘Lvmeng' was induced by artificial chemistry, with thickened leaves, deepened leaf color, thickened stem, petiole, bracts stalk and spadix, which greatly improves the ornamental value of S. floribundum.