在广泛收集我国薏苡（Coix  L.）种质资源，进行田间栽培，杂交试验和细胞学观察的基础上，讨论薏苡属植物的遗传多样性、地理分布及种类划分，在原１种２变种的分类基础上，把我国的薏苡属植物划分为３种４变种。根据这些种类的１８个栽培及野生类型的染色体核型演化散点图并结合总苞性状，探讨了该属可能的系统演化关系。

Basing on cultivation, cross-compatibility and cytological observation, the genetic diversity, distribution and classification of Chinese Coix L. were investigated. It is found that the local cultivars, which have the same flowering time, easily cross each other by natural or artificial ways. As a result, a series of new cultivars with different shapes, sizes, colours and hardiness of involucres have been formed and there are plenty of germplasm resources of Coix L. in China. According to the cross-compatibility and features of cultivated and wild or semi-wild taxa in Chinese Coix L. 3 species and 4 varieties are recognized. The karyotypes of 18 samples (belonging to 3 species and 4 varieties) were observed. The karyotype formulae are as follows : Coix puellarum 2n = 20= 20m ; C. stenocarpa 2n = 20= 18m+2sm;C. lacryma-jobi, var. lacryma-jobi 2n = 20 = 18rn + 2srn and 2n = 20 = 16m + 4sm, var. monilifer 2n = 20 = 12m + 2m^sat+ 6sm. var. mayuen 2n = 20 = 14m + 2m^sat+ 4sm. var. formosana 2n = 20 = 14m + 6sm + (+ 1 – 2B ) . According to the scatter diagram of karyotypic evolution of Coix L. the relationships of 3 species and 4 varieties are discussed.