Legume Genomics and Genetics 2025, Vol.16, No.6, 297-312 http://cropscipublisher.com/index.php/lgg 299 gibberellins are also indispensable in pea podding. As early as the pollination stage, exogenous spraying of appropriate amounts of GA can induce unfertilized pea ovaries to develop into seedless pods, reflecting the promoting effect of GA on fruit growth. Under normal pollination conditions, ovule development is also accompanied by the activation of the GA synthesis pathway, so that pods and seeds develop synchronously. In addition, cytokinins contribute to the cell division of the embryo and endosperm, and abscisic acid (ABA) accumulates during the seed maturation stage to promote embryo maturation. The temporal and spatial interactions of these hormones jointly determine the final pod and seed setting (Miryeganeh, 2022). It is worth noting that ethylene is often regarded as an "aging hormone", and its excessive content will promote the shedding of flowers and young pods. Under adverse conditions, the ethylene level in plants may increase, which will have a negative impact on pod setting. Therefore, the formation of pea pods is the result of the balance of multiple hormones: growth hormones (such as IAA, GA, cytokinin, brassinolide, etc.) provide positive signals to maintain pod and seed development; while inhibitory hormones (such as ABA, ethylene) may cause pod failure if they appear too early or in excess. By regulating the balance of hormones, the pod setting rate of peas can be affected to a certain extent. For example, field experiments have found that timely spraying of growth regulators (such as gibberellins or brassinosteroids) can reduce the shedding of flowers and pods and increase the number of pods. Overall, endogenous hormone levels and sensitivity are important internal factors that determine the success or failure of pea pod setting. Figure 1 Schematic representation of pod elongation (A) and seed filling (B) stages of pea reproductive development. 4-Cl-IAA, 4-chloroindole-3-acetic acid; TAR, tryptophan aminotransferase related; YUC, yucca; GA, gibberellic acid; GAox, gibberellic acid oxidase; ERS1, ethylene response sensor 1; ETR1, ethylene receptor 1; UDPG, uridine diphosphate glucose; G6P, glucose-6-phosphate; TPS, trehalose phosphate synthase; AGPase, adenosine diphosphate glucose pyrophosphorylase (Adopted from Bal and Østergaard, 2022) 2.3 Integrated effects of environmental factors The pod setting process of peas is affected by a variety of external environmental factors at the same time, among which light, temperature, moisture and other conditions are particularly critical (Naveed et al., 2024). First, sufficient light ensures the accumulation of photosynthetic products and provides energy and nutrition for pod and seed development. If the flowering and podding period encounters continuous cloudy days, the light intensity and duration will be significantly reduced, which will lead to a decrease in the photosynthetic rate of the plant, and the synthesized organic matter will be insufficient to support the growth of new pods and grains, thereby increasing the risk of young pods falling off (Zhao et al., 2019). The photoperiod will also affect the flowering and podding rhythm of peas. Peas are long-day plants. Under conditions of shortened daylight, flowering may be delayed and
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