Abstract: 【Objective】In a survey for cyst nematodes in Jiangxi Province, China, a cyst nematode population was collected and extracted from soybean roots and rhizosphere soil. The morphological characteristics of this population are different from that of the soybean cyst nematode (Heterodera glycines). The objective of this study is to research morphological and molecular characteristics and parasitism test of this population, identify their species and parasitism to legume crops, and to provide scientific basis for disease prevention and control.【Method】Soil samples were collected in Wuyuan County, Shangrao City, Jiangxi Province. The cysts were collected by sieving method or dissected from the roots. The 2nd stage juveniles (J2s) and males in soil were extracted by using the shallow disk method. The cysts with typical characteristics were selected to make a slice of the vulva cone, the J2s and males separated by shallow disk method were made into permanent slides. Morphological characteristics of cysts, J2s and males were observed and measured under microscope. For molecular studies, single cyst from soybean roots was picked and then ground to extract the genomic DNA. The ribosomal RNA-ITS region and the D2-D3 expansion segments of 28S large subunit rRNA gene were amplified with universal primers AB28, TW81 and D2A, D3B, respectively. The sequencing results were deposited in the GenBank database and compared with nematode sequences using the BLAST homology search program. The closest sequences were selected for phylogenetic analyses. The MEGA software was used to construct the ITS and LUS D2-D3 phylogenetic tree of cyst nematodes using neighbor-joining method. The parasitism of this cyst nematode to 11 legume crops and 40 soybean cultivars was tested by artificial inoculation in greenhouse. 【Result】 Morphological characteristics of cysts, J2s and males of population in this study agreed with Heterodera sojae reported in Korea. Sequence from the ITS-rDNA (MG859982) was 99% and 98% identical to those of H. sojae from Korea (KU160510 and KU160512) and only 81% identical to the soybean cyst nematode (H. glycines) (KY794762.1). The D2-D3 (MG859981) sequence was 99% identical to H. sojae from Korea (KU160511). In addition, analysis of phylogenetic trees constructed by the ITS and LUS D2-D3 both showed that the Jiangxi population and H. sojae were grouped in the same clade with a reliability of 100%. The cyst nematode population from Jiangxi was identified as H. sojae - a new record species in China. Inoculation of 11 legume crops showed that J2s of H. sojae could infect 10 crops (soybean, jequirity, cowpea, pea, lentil, mung bean, adzuki bean, sword bean, green beans and alfalfa), but could complete the life cycle only on soybean and jequirity. Soybean cultivars resistant identification test results showed that 19 cultivars of the 40 inoculated soybean cultivars were highly susceptible, 11 cultivars were moderately susceptible, 5 cultivars were moderate resistant and 5 cultivars were highly resistant.【Conclusion】The population of cyst nematode collected on soybean from Jiangxi, China was identified as H. sojae - a new cyst nematode record in China. Parasitism tests indicated that soybean and jequirity were suitable hosts for H. sojae, and 30 of the 40 soybean cultivars were susceptible to phenotypic disease of cyst nematodes. 

Key words: Heterodera sojae, new record in China, morphology, molecular identification, parasitism