African root and tuber scale (ARTS) Stictococcus vayssierei Richard is a serious constraint to the production of cassava (Manihot esculenta Crantz) in Central Africa, and the food and income security for smallholder farmers. Therefore, to improve the production of cassava it is urgent to determine the appropriate cultural practices that lower ARTS infestation pressure. This study tests the single and combined effects of stem cutting portion and crop variety on ARTS infestation levels’. A split-plot design with four cassava varieties (TMS 96/0023, Excel, Miboutou and Douma) as the main plots and three stem cuttings portions of these varieties (lower, middle and upper portions of the mother plant) as sub-plots was used. The results showed that at 12 months after planting (MAP), lower portions of the local variety Douma showed the highest fresh shoots (2.95 ± 0.13 kg) than the upper portions (2.08 ± 0.09 kg) of the Excel variety. The portions at lower of the Excel variety were the most infested (118-158.38 and 126.75 ARTS) at 3, 6 and 9 MAP respectively. The yield of local variety Douma was higher (20.00-20.11 t ha− 1) in plots planted with portions at middle and lower, followed by yields of TMS 96/0023 variety (19.00 t ha− 1) in plots planted with the lower portions. Overall, irrespective of the cassava variety, the lower portion 16.49 t ha− 1 resulted in higher yield than those the upper portion 10.81 t ha− 1.

中文翻译：

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作物基因型和茎切割部分影响喀麦隆热带雨林木薯根鳞片 Stictococcus vayssierei Richard（半翅目：Stictococcidea）的侵染压力

非洲块茎鳞屑病 (ARTS) Stictococcus vayssierei Richard 严重限制了中非木薯 (Manihot esculenta Crantz) 的生产以及小农的粮食和收入安全。因此，为了提高木薯的产量，迫切需要确定降低 ARTS 侵染压力的适当文化做法。本研究测试了茎切割部分和作物品种对 ARTS 侵染水平的单一和综合影响。以 4 个木薯品种（TMS 96/0023、Excel、Miboutou 和 Douma）为主地块，以这些品种的 3 个茎插部分（母株的下部、中部和上部）为子地块的裂区设计是用过的。结果表明，在种植后 12 个月（MAP），与 Excel 品种的上部 (2.08 ± 0.09 kg) 相比，本地品种 Douma 的下部显示出最高的新鲜芽 (2.95 ± 0.13 kg)。Excel 品种较低的部分分别在 3、6 和 9 MAP 受侵染最多（118-158.38 和 126.75 ARTS）。地方品种豆马的产量在中下部种植地块较高（20.00-20.11 t ha− 1），其次是TMS 96/0023品种（19.00 t ha− 1）在下部种植地块. 总体而言，无论木薯品种如何，下部 16.49 t ha-1 的产量高于上部 10.81 t ha-1 的产量。地方品种豆马的产量在中下部种植地块较高（20.00-20.11 t ha− 1），其次是TMS 96/0023品种（19.00 t ha− 1）在下部种植地块. 总体而言，无论木薯品种如何，下部 16.49 t ha-1 的产量高于上部 10.81 t ha-1 的产量。地方品种豆马的产量在中下部种植地块较高（20.00-20.11 t ha− 1），其次是TMS 96/0023品种（19.00 t ha− 1）在下部种植地块. 总体而言，无论木薯品种如何，下部 16.49 t ha-1 的产量高于上部 10.81 t ha-1 的产量。