Effect of leaf thinning on shoot growth and tuber yield of white Guinea yam

Abstract

Mutual leaf shading can inhibit the growth of yam, reducing tuber yield. To improve light utilization, approximately 25% of leaves in a plant were thinned during the period of maximum shoot growth. Shoot dry weight was estimated every two weeks using a non-destructive method. Leaf thinning caused higher shoot growth rates (SGRs) after thinning, while control plants had SGRs close to zero. The higher SGRs in the thinned plants was attributed to an increase in new leaf development. This indicates that the plateau in shoot growth commonly observed during the late growth period is reversible and could be improved artificially. In thinned plants, there was a positive relationship between shoot dry weight and SGR, although no such relationship was observed in control plants after the middle growth period. This positive correlation indicates a higher shoot growth per unit leaf area in the thinned plants than in the control plants, presumably due to improved light utilization and a higher photosynthetic rate of new leaves. However, leaf thinning reduced tuber yields, presumably because of a lower total carbon assimilation per plant and greater growth competition between shoots and tubers. High correlations between shoot dry weight and tuber yield indicated that a high shoot biomass is more important than improving light utilization for increased tuber yields.

Variability of Flowering Sex and Its Effect on Agronomic Trait Expression in White Guinea Yam

“…In addition, the negative relationship between flowering date and tuber yield is thought to be caused by resource competition with tuber enlargement. Normally, tuber enlargement starts in late August (around DOY 240) at the experimental site ( Vaillant et al, 2005 ), after which leaf development is retarded due to resource competition ( Marcos et al, 2011 ; Iseki et al, 2021 ). Therefore, late-flowering occurring after late August restricts the utilization of carbon resources for tuber enlargement.…”

Biomass production and nutrient use efficiency in white Guinea yam (Dioscorea rotundata Poir.) genotypes grown under contrasting soil mineral nutrient availability

“…Therefore, the size of shoot biomass or leaf density as a morphological traits, associated with plant demand for nutrients, might be a factor contributing to varietal difference in fertilizer or soil NPK responsiveness among the tested genotypes. Iseki et al (2022) reported a positive correlation between shoot biomass and tuber yield and pointed out that shoot growth is important for final tuber yield. Therefore, increasing shoot growth by fertilizer application may improve tuber yield in white Guinea yam genotypes with a high response to fertilizer input.…”

“… Iseki et al. (2022) reported a positive correlation between shoot biomass and tuber yield and pointed out that shoot growth is important for final tuber yield.…”

Effects of Phosphorus and Zinc on Net Assimilation Rate (NAR) of Cowpea (<i>Vigna unguiculata</i> (L.) Walp) Varieties Grown in Bauchi, Nigeria

“…Similarly, the decrease in NAR as the plant becomes older may attributed to older average leaf age which leads to decreased photosynthetic efficiency (Martín-Hernández et al, 2016;Putul et al, 2021). NAR was observed to decrease with age due to mutual shading of leaves as plants age and thus decreased assimilation rate (Fageria et al, 2006;Addo-Quaye et al 2011 andMuhammad, 2011;Iseki et al, 2022).…”