我国狗牙根种质资源形态变异及形态类型划分

Morphological variation and types of Cynodon dactylon

对我国444份狗牙根种源15个外部性状的变异及其规律进行了统计及聚类分析,结果表明,1)我国狗牙根不同种源外部性状具有广泛的变异性,其中,在高度(草层高度、生殖枝高度)、营养器官长度(叶片长度和节间长度)以及株型(短茎形态和形态指数)等方面变异最大;其次为狗牙根的均一性、密度和叶色等方面的变异;狗牙根在宽度方面的变异(如叶片宽度和节间直径)均较小,在穗部性状(穗长、小穗长度和穗支数)方面的变异幅度最小。2)随着我国狗牙根种源由南向北分布,其草层高度和生殖枝高度显著增加,叶片显著变长变宽,节间显著变长,小穗长度明显增加,穗枝数明显减少,叶色愈深,密度愈高,匍匐性愈强。与西部狗牙根相比,东部狗牙根总的来说种源节间和小穗显著较长,而生殖枝高度显著较低。3)在欧氏距离13.2处,可将我国狗牙根种源分为5个形态类型,其坪用价值排序为粗高型<直立型和斜高型<斜矮型<矮生型。根据其形态特征和坪用价值,粗高型可用于牧草,即牧草型狗牙根,直立型狗牙根、斜高型狗牙根以及斜矮型狗牙根坪用价值适中,可用于各种类型的保土草坪,而矮生型低矮致密,色泽宜人,适用于公共绿地、运动草坪乃至高尔夫球场球道或发球台草坪。

The morphological variation between 444 populations of Cynodon dactylon was analyzed, and clustering was carried out based on 15 morphological characteristics. The results showed that: 1) Abundant morphological variation existed between populations of C.dactylon. The largest variation was found in characteristics including height (including turf and reproductive stem height), length (including leaf and internode length) and shoot morphology (referring to short stem form and morphological index); followed by variation in characteristics including uniformity, density, and leaf color. The least variation was found in characteristics including width (referring to leaf width and internode diameter) and inflorescence character (referring to inflorescence and spikelet length, and inflorescence branch number). 2) With latitude increasing, C.dactylon became higher and more erect with longer leaves and internodes. The reproductive stem height also became much higher with longer inflorescences and spikelets, but the inflorescence branch number reduced. The populations also produced darker green leaves and denser turf. Populations from east China compared with those of the west generally had longer internodes and spikelets, but lower reproductive stem height. 3) Based on 15 morphological characteristics, populations were clustered into five morphological types with turf quality ranked as follows: coarse-high type < erect and slanting-high types < slanting-dwarf type < dwarf type. It was suggested that the coarse-high type be used for forage; that the erect, slanting-high, and slanting-dwarf types could be used for soil protection; and that the dwarf type could be used for places including golf courses, public green land, and sports fields.