Growth of yacon under artificial shading

ABSTRACT Yacon is a tuberous root cultivated in mild climate regions with high altitudes, but the crop shows the capacity to develop at low altitudes. The objective of this study was to evaluate growth rates and the partition of photoassimilates in yacon plants under different levels of artificial shading. The experiment was conducted in four shading levels (0%, 30%, 50% and 70%), and seven monthly harvests in a completely randomized design. We evaluated the accumulation of total dry mass on the whole plant and its parts; leaf area; leaf area ratio; leaf mass fraction; stem mass fraction; rhizophores mass fraction; tuberous roots mass fraction; estimates of relative growth rate, absolute growth, and net assimilation. The lower accumulation of total dry biomass and the lowest growth rates indicate that conditions of noticeable light restriction (70% shading) restrict the growth of yacon. Yacon plants grown under moderate shading levels (30 to 50%) showed greater capacity of accumulation of total biomass, directing part of this biomass to the tuberous roots, which directly reflects gains in the agronomic productivity of this crop, indicating that yacon has the potential to be associated with other crops, which promote a moderate shading.

摘要：菊薯（Yacon）是一种在高海拔温和气候区种植的块根类作物，但该作物也具备在低海拔地区生长的能力。本研究旨在评估不同人工遮阴水平下菊薯植株的生长速率及光同化物分配情况。实验设置4个遮阴梯度（0%、30%、50%与70%），采用完全随机设计，共开展7次月度收获。本研究测定了整株及各器官的总干物质积累量、叶面积、叶面积比、叶质量分数、茎质量分数、根状茎质量分数、块根质量分数，以及相对生长速率、绝对生长量与净同化速率的估算值。结果显示，重度光照限制条件下（70%遮阴），总干生物量积累量最低且生长速率最慢，表明强遮阴会抑制菊薯生长。而在中度遮阴水平（30%~50%）下种植的菊薯，总生物量积累能力更强，且会将部分生物量分配至块根，这直接提升了该作物的农艺生产力，表明菊薯具备与其他可提供适度遮阴的作物间作的潜力。