一年生苜蓿种质资源形态变异及其形态特征

以22份一年生苜蓿为材料，对生育期和外部形状进行观测和统计分析，并对形态类型加以聚类分析。结果表明：（1）一年生苜蓿的茎为直立或匍匐，茎高在7．0～30．7cm，3出羽状复叶，种子为黄色、肾形。生育期在95—140d，从生育天数可分为早熟型和晚熟型；（2）一年生苜蓿种内变异很大，其中主茎长度和自然高度的变异系数最大，分别为43．0％和42．9％。其次是叶长和叶宽，变异系数分别为33．3％和30．0％。而第2主茎长度变异系数是27．6％，伸展长度变异系数22．1％；（3）对一年生苜蓿在干旱地区和高寒地区的生长状况的比较发现，一年生苜蓿更适应于干旱地区的生长；（4）一年生苜蓿的主茎长度越长，第2主茎长度越长，自然高度越高，伸展长度越长，叶长和叶宽也越长；（5）通过形态类型的聚类分析，可将一年生苜蓿分为3个类型，直立型，匍匐型和低矮型。

Morphological variations and characters of annual medic germplasm resources

The developmental stage,external shape and characters in 22 accessions of annual medics were analyzed statistically and their morphological types clustered.The results show that:(i) The stem of annual medics was erection type or stolon type,and the stem heights reached 7.0～30.7 cm.The seeds were yellow and kidney shape,and the developmental period lasted 95～140 days.The accessions of annual medics were divided into prematurity type and serotinous type according to the developmental stage.(ii)shapes and characters among the accessions of annual medics varied greatly.The coefficients of variation for caulis length and nature height were 43.0% and 42.9% respectively,followed by leaf length and leaf width with the coefficients of variation reached to 33.3% and 30.0%.The coefficients of variation of the second caulis and spread length reached to 27.6% and 22.1%.(iii)Annual medics are adapted to grow better in drought area than in high altitude area.(iv)The longer of the main caulis in accessions was the higher of the second caulis and the natural height,and the higher spread length always boast higher leaf length and leaf width.(v)The accessions of annual medics were divided into three morphological types by cluster analysis of morphological type,i.e.erection type,stolon type,and low type.