A leaf bud technique for rapid propagation of cassava (Manihot esculenta Crantz)

ABSTRACT The slow rate of multiplication is one of the main constraints on the production of cassava (Manihot esculenta Crantz). This work aimed to evaluate the use of leaf buds for rapid propagation of cassava varieties. Leaf buds were excised from three cassava varieties (BRS Kiriris, 98150-06 and 9624-09) for plantlet generation. The experiment was completely randomized with a 5 (age of mother plant) × 3 (position of the leaf buds on the stems) × 2 (agrochemical treatments) factorial design. Data were collected on leaf sprouting percentage (Spro.Per), plantlet height (Plant.Hei) and total dry mass of plantlets (Dry.Mass.Plant). There was a difference between the three traits for most of the varieties, demonstrating significant effects on the agronomic attributes evaluated. Better agronomic performance (higher sprouting percentage, plantlet height and total dry mass) in plantlets was observed in leaf buds of: i) maturing plants up to six months old; ii) more herbaceous (upper) parts; and iii) plants treated with agrochemicals (fungicides and insecticides). Considering four-month-old plants, three annual cycles, and an 81 % average sprouting, it would be possible to reach an annual multiplication rate of 1:72, which is much higher than that achieved by traditional methods using mature stem cuttings from 12-month-old plants (around 1:5). These results are important because they demonstrate the possibility of using cassava leaf buds to produce high-quality plantlets rapidly for greater multiplication and diffusion of new varieties and cultivation on a larger scale.

摘要 繁殖速率缓慢是制约木薯（Manihot esculenta Crantz）生产的主要瓶颈之一。本研究旨在评估利用叶芽快速繁殖木薯品种的可行性。研究从三个木薯品种（BRS Kiriris、98150-06和9624-09）上切取叶芽用于幼苗培育。本试验采用完全随机化的5（母株株龄）×3（叶芽在茎上的着生位置）×2（农用化学品处理）析因设计。试验采集了叶芽萌发率（Spro.Per）、幼苗株高（Plant.Hei）及幼苗总干重（Dry.Mass.Plant）三项指标数据。多数木薯品种的三项性状均存在显著差异，表明各评估农艺性状均受到显著影响。研究发现，取自以下三类母株的叶芽所培育的幼苗农艺表现更佳（萌发率更高、株高更优、总干重更大）：i）株龄不超过6个月的成熟母株；ii）茎部草质化程度更高的上部区域；iii）经农用化学品（杀菌剂与杀虫剂）处理的母株。若以株龄4个月的母株为材料，开展3个年度繁殖周期，且平均萌发率达81%，则年度繁殖倍率可达1:72，远高于传统方法（采用12月龄母株的成熟茎段扦插，繁殖倍率约为1:5）。本研究结果具有重要意义，其证实了利用木薯叶芽快速培育优质幼苗的可行性，可实现木薯新品种的高效繁殖与推广，并为规模化种植提供支撑。