Effects of <i>Meloidogyne enterolobii</i> and <i>Meloidogyne javanica</i> initial population density (Pi) on potato cultivars’ plant height (PH), stem diameter (SD), chlorophyll content (CC), fresh weight (FW), dry weight (DW), tuber number (TN) and tuber weight (TW) at 56 days after inoculation under net house conditions.

Potato (<i>Solanum tuberosum</i> L.) is a well-known food crop that is regarded as an important component in the worldwide battle against hunger and malnutrition. Root-knot nematodes (RKN), <i>Meloidogyne</i> species, are a serious limitation in the potato industry. Potato, being a tuberous crop, yield reduction is mainly due to tuber quality and quantity. In order to evaluate the response of five commercial potato cultivars, <i>viz</i>, ‘Buffelspoort 1’, ‘Hertha’, ‘Larnoma’, ‘Mnandi’ and ‘Up-to-date’ to two RKN species, <i>viz</i>, <i>M. enterolobii</i> and <i>M. javanica</i>; pot experiments were conducted under net house conditions. Ten separate experiments, each with treatments: 0, 500, 1500, 2500 and 3500 eggs + second-stage juveniles (J2), were arranged in a randomized complete block design (RCBD) with five replicates. Fifty-six days after inoculation, nematode effect on plant yield was evaluated. Potato tubers were assessed for root galls and nematodes reproductive factor (RF) was computed. There were significant differences amongst treatments on the following potato growth parameters: plant height, stem diameter, chlorophyll content, number of tubers and tuber weight in both <i>M. enterolobii</i> and <i>M. javanica</i> (P ≤ 0.05). The RF was above unity (one) in all potato cultivars for both <i>M. enterolobii</i> and <i>M. javanica</i>; with <i>M. enterolobii</i> showing more aggressiveness compared to <i>M. javanica</i>. Further, cultivars ‘Buffelspoort 1’ and ‘Hertha’ showed the highest susceptibility, whilst cultivar ‘Mnandi’ showed the least susceptibility. Infection of potato cultivars by the nematodes had severe effects on growth parameters of all the cultivars. Results suggested that all five commercial potato cultivars were susceptible to <i>M. enterolobii</i> and <i>M. javanica</i>. Thus, there is an urgent need for RKN management intervention in the aforementioned cultivars.

马铃薯（*Solanum tuberosum* L.）是全球重要的粮食作物，被视作全球抗击饥饿与营养不良斗争的重要组成部分。根结线虫（Root-knot nematodes, RKN）即根结线虫属（*Meloidogyne*）物种，是马铃薯产业的严重制约因素。作为块茎类作物，马铃薯的产量损失主要源于块茎品质与数量的下降。为评估5个商用马铃薯品种，即‘Buffelspoort 1’、‘Hertha’、‘Larnoma’、‘Mnandi’和‘Up-to-date’，对两种根结线虫物种，即*M. enterolobii*与*M. javanica*的响应，本研究在网室条件下开展了盆栽试验。

试验共设置10组独立处理，每组处理的接种物为0、500、1500、2500、3500个卵+二龄幼虫（second-stage juveniles, J2），采用完全随机区组设计（Randomized Complete Block Design, RCBD），设置5次重复。

接种56天后，评估线虫对植株产量的影响。对马铃薯块茎的根结情况进行观测，并计算线虫繁殖系数（Reproductive Factor, RF）。

在*M. enterolobii*与*M. javanica*两种线虫侵染下，各处理间在株高、茎粗、叶绿素含量、块茎数量及块茎鲜重等马铃薯生长参数上均存在显著差异（P ≤ 0.05）。两种线虫侵染的所有供试马铃薯品种的繁殖系数均大于1，且*M. enterolobii*相较于*M. javanica*表现出更强的侵袭性。进一步分析显示，‘Buffelspoort 1’与‘Hertha’两个品种的感病性最高，而‘Mnandi’的感病性最低。

线虫侵染对所有供试品种的生长参数均造成了显著负面影响。研究结果表明，上述5个商用马铃薯品种均对*M. enterolobii*与*M. javanica*敏感。因此，针对上述品种开展根结线虫防治工作已刻不容缓。