Effect of Source–Sink Ratio Manipulation on Growth, Flowering, and Yield Potential of Soybean

Abstract

Trade-offs between growth and reproduction in soybean require resource availability manipulations. Decapitation and reducing sink strength through deflowering can affect the source–sink ratio that affects plant growth, development, and yield. The current study assesses the effect of decapitation (Decap) and removal of the two lowest racemes (R2LR) and their combination on growth, flowering, and yield capacity of soybean through controlling the source–sink ratio and inducing the “stay-green” phenotype. Two field experiments were conducted during 2018 and 2019 in the Agronomy Farm located at Mansoura University, Egypt. Decapitation was done at the V4 stage (35 days after sowing, DAS), during which four nodes on the main stem had fully developed leaves beginning with the unifoliolate nodes, whereas R2LR was performed at the R2 stage (50 DAS), during which the plants had one open flower at one of the two uppermost nodes on the main stem. Results indicated that Decap, R2LR, and their combination significantly increased seed yield per plant through increasing plant growth and flowering and improving biochemical attributes. The combination between Decap and R2LR was generally more effective in positively modulating plant vegetative, reproductive, and physiological capacity than either Decap or R2LR alone. Moreover, the number of branches as well as pods/plant and IAA content responded positively to Decap, whereas net assimilation rate, seed growth rate, number of flowers/node, and cytokinins content responded positively to R2LR. Decap and R2LR were interpreted in light of their effects on inducing the “stay-green” phenotype and altering the source–sink ratio. Based on the findings, it can be concluded that concealing the apical dominance in conjunction with reducing the sink strength through guided raceme removal would be beneficial for the reproductive potential in soybean.

Spermidine Suppressed the Inhibitory Effects of Polyamines Inhibitors Combination in Maize (Zea mays L.) Seedlings under Chilling Stress

“…Agricultural crops are confronted by a number of abiotic stress factors that limit their productivity [1][2][3][4][5]. Among abiotic stresses, chilling stress is one of the most severe stresses, which substantially inhibits the seed germination and seedlings development [6].…”

Effect of terminal bud clipping on growth and yield of soybean cultivars in the Pacific Northwest

“…Significantly taller plants were observed with control (109.28 cm) compared to early and late clipping treatments (100.10 and 100.43 cm). The reduction in the plant height with terminal bud clipping might be due to the effect of breaking the apical dominance, whereas the taller plant growth in control might be due to the continuous supply of auxin to meristematic tissues (Venkadachalam, 2003; Kokilavani et al., 2007; Ibrahim et al., 2021; Kocjan Acko et al., 2019; Siddagangamma et al., 2018). As in terminal clipping practice, the apical bud is removed, and so the utilization of the photosynthates by the crop for lateral branches could be higher, and this might be the reason for decreased plant height.…”

“…Early clipping treatment resulted in the lowest pod height of 10.75 cm compared to control and late clipping treatments (Table 2), suggesting that the removal of the terminal bud might have activated dormant axillary buds forming new lateral branches and shoots (Ibrahim et al., 2021), resulting in the lowest pod height. Though there was no significant difference in plant height between early and late clipping, the plants were slightly shorter with early clipping, which might have resulted in pods developing low (Table 2).…”

“…It can provide the raw material for specialized food products and et al, 2007;Ramanathan & Chandrashekharan, 1998). This method resulted in exceptionally high soybean yields in Egypt (Ibrahim et al, 2021). Similarly, Kokilavani et al (2007) found that sesame yield increases with terminal bud removal by improving the crop architecture and yield attributes.…”

Evolving role of synthetic cytokinin 6-benzyl adenine for drought stress tolerance in soybean (Glycine max L. Merr.)

“…This study recommended the use of 150 mgL −1 6-BAP as part of the irrigation program to compensate reduced water supply of up to 80% of crop evapotranspiration in soybean. Other studies that have exploited 6-BAP due to its crucial role in soybean plant growth and development include Abdallah (2020), Mangena (2020), Ibrahim et al (2021), and Amoanimaa-Dede et al (2022).…”