Inflorescence Removal Affects Root Yield of American Ginseng

Abstract

<jats:p>Manual removal of inflorescences from mature (3- and 4-year-old) American ginseng plants (<jats:italic>Panax quinquefolium</jats:italic> L.) at commercial timing (early July, ≈25% flowers open) increased root yield at harvest. Consecutive inflorescence removal for 2 years (third and fourth) increased yield 55.6%. Inflorescence removal in 4-year-old plants increased yield by 34.7% compared with 26.1% in 3-year-old plants. Analysis showed that the largest portion of roots (≈40%) was in the medium category (10-20 g), and inflorescence removal did not influence root size distribution. Root yield for 3-year-old plants increased quadratically with plant density, with plants lacking inflorescences having an estimated yield increase of 25%. Maximum yields of 2.4 kg·m<jats:sup>-2</jats:sup> for deflowered plants were achieved at a plant density of 170 plants/m<jats:sup>2</jats:sup>. To maximize ginseng root yield, all plants except those needed to provide seed for future plantings should have inflorescences removed.</jats:p>

Phosphorus fertilization and inflorescence removal in American ginseng culture

“…The inflorescence removal in the 2nd and 3rd year (and no removal in the last one) was connected with significant, on average, a 31% higher root yield and 16.5% leaf and stem yield. That was in agreement with the studies by Proctor et al, (1999), Fiebig (1999), and Proctor et al, (2011), although the root-weight increases in our experiments were slightly higher. When inflorescence removal treatment was performed only in the second year of cultivation, the yields of the aerial parts (leaf and stem) and roots were higher by 10% (Table 1).…”

“…The yield of roots collected from the plants treated with the low dose of phosphorus fertilization (26.2 kg P ha −1 ) were on average 40% higher than those obtained in the control plots, whereas the application of the higher phosphorus doses resulted in over double the raw material yield. However, it should be borne in mind that for extrapolation of root yields from g m −2 to t ha −1 , an estimate of two-thirds of actual cropping area should be used (Proctor et al, 1999). The same tendency in root weight increase with increasing phosphorus doses was observed by .…”

“…The total exports from North America in 2013 were 3150 tons, which represented above 50% of world production of American ginseng and about 10% of global ginseng flowering and fruiting; it also increases plant resistance to diseases (Li, 1995). On the other hand, although the ginseng inflorescence is economically unimportant, it is still considered important due to its vital role in species propagation (Proctor et al, 1999). Ginseng begins to produce spherical, umbel-shaped inflorescence in May of the second year.…”

Morphological and Ginsenoside Differences among North American Ginseng Leaves

“…Ginsenoside content varies depending on plant part and age [15], fertility level [16,17], harvest date [18] and light levels [19]. The effect of the established practise of manual inflorescence removal to increase root yield [13] on ginsenoside content has not been reported so was investigated in this study.…”

“…Leaf area of ginseng has been reported [12] but internal structure has not although it has implications for leaf photosynthesis. Manual inflorescence removal increases ginseng root yield by 26% [13] but nothing is known about the effect of this removal on leaf physical properties. We therefore addressed these characters in these studies.…”