Minituber production in yam for alternative vegetative propagation: types of cuttings, substrates, and anatomy

ABSTRACT: Yam is a tuber vegetable crop with vegetative propagation. The crop is low yielding due to the difficulty of obtaining quality material for propagation and the high cost of acquisition. The cutting technique is a new alternative for vegetative propagation of yam. The present studyevaluated the production of minitubers of yam through cuttings, and follow the formational growth of the minitubers. Different types of cuttings, obtained from three positions on the shoots, and three substrates were tested. The types of cuttings and substrates did not significantly affect the number of minitubers per cutting, this number ranging from 1.18 to 1.75. The best results were obtained using Tropstrato Florestal® and median-position cuttings for the following variables: minituber length (17.47 mm), minituber diameter (12.63 mm), minituber fresh weight (2.12 g), and percentage of cuttings with two minitubers (75%). Anatomical analysis showed cell divisions and starch accumulation in the nodal region at seven days after planting the cutting. Emergence of the minituber could be observed at 21 days. The production of yam minitubers through stem cuttings is enhanced using cuttings obtained from the median position of the shoot and using the commercial substrate Tropstrato Florestal®.

摘要：山药是一种采用无性繁殖的块根类蔬菜作物。由于优质繁殖材料获取困难且购置成本高昂，该作物产量偏低。扦插技术是山药无性繁殖的新型替代方案。本研究评估了通过扦插繁育山药微型块茎（minituber）的效果，并追踪了微型块茎的形成与生长过程。试验设置了三种嫩梢取材部位的扦插类型与三种栽培基质开展测试。结果表明，扦插类型与栽培基质对单扦插穗的微型块茎数量无显著影响，该数值区间为1.18~1.75。采用Tropstrato Florestal®商品基质与中部茎段扦插穗时，可在以下指标中获得最优表现：微型块茎长度（17.47 mm）、微型块茎直径（12.63 mm）、微型块茎鲜重（2.12 g）以及双微型块茎扦插穗占比（75%）。解剖学分析显示，扦插定植7天后，茎节区域即出现细胞分裂与淀粉积累现象；扦插后21天可观察到微型块茎的萌发。综上，选取嫩梢中部的扦插穗并配合商品基质Tropstrato Florestal®，可提升山药茎段扦插微型块茎的生产效果。