Pod Growth Research Articles

Disease Incidence of Leaf Rust of Soybean Caused by Phakopsora pachyrizi Planted in Mahogany Agroforestry System

Abstract Soybean (Glycine max L.) is one of the agricultural commodities needed in high quantities in Indonesia. Using agroforestry systems for soybean cultivation can solve the domestic fulfillment of soybean needs. The moist environmental conditions of agroforestry plantings due to shading make soybeans susceptible to leaf rust disease. The pathogen Phakopsora pachyrhizi causes leaves to fall off early, inhibiting soybean seed pod growth. Research on the incidence of leaf rust disease in several soybean varieties is essential to optimize soybean production in agroforestry systems. The study was conducted from June to October 2023 in the Special Purpose Forest Area (KHDTK) of Alas Bromo, Karanganyar, Central Java, Indonesia. The experiment used a randomized experimental design (RAK) with seven soybean varieties: Anjasmoro, Agromulyo, Dena-1, Dena-2, Denasa-1, Denasa-2, and Devon-1. Disease incidence observation was based on visual symptoms. The disease incidence was in the range of 3.33-26.67%. The highest incidence occurred in the Denasa-1 and Dena-2 varieties, while the lowest was in the Anjasmoro and Dena-1 variety.

Effects of concentration and time of brassinosteroid treatment on growth and yield of soybean under drought stress conditions

Soybean (Glycine max (L.) Merrill.) is an essential food and industrial crop, but it can be heavily affected by drought, especially during the pod growth stage. Brassinosteroids (BRs) are reported to alleviate drought stress, but the effectiveness may depend strongly on BR concentration and timing of the application, and no research has investigated this issue. This study aimed to determine the suitable concentration of BRs and time of treatment to help soybean plants withstand drought conditions during pod growth. The experiment was conducted with a completely randomized design, with four concentrations of BRs: 0 ppm (water) (B0), 0.1 ppm (B1), 0.2 ppm (B2), 0.3 ppm (B3), and three-time points for the application of BR treatment: soaking before sowing (T1), leaf spray when 50% of plants flowered (T2), leaf spray when 50% of the plants had pod at least 0.5 cm in length (T3). The results showed that when treated with different concentrations and treatment times of BRs, there was no difference in plant growth and development. However, there were differences in the yield of soybean plants. Specifically, treatment B2T2 had the highest total number of firm pods and the highest number of firm seeds at 22.2 and 44.6, respectively, with the weight of 100 seeds reaching 17.9 g, leading to the highest actual yield of 97.0 g/plot. These results indicate that with appropriate concentration and timing (0.2 ppm during flowering), the application of BRs can significantly alleviate drought stress effects on soybean plants during pod growth, improving seed yield and quality.

Peanut maturity detection assessment using cross-layer multi-perception neural network based on hyperspectral sensory image feature observation

Artificial intelligence has played a significant role in the expansion of the agriculture industry in recent times by evaluating data and making recommendations for better production. An automated method for determining significant information in seed quality analysis is the peanut maturity analysis in image processing through sensory images. The majority of the time, changes in picture intensity result in feature independence and precise maturity level determination. Therefore, agricultural precision in identifying essential features is low. To address this issue, we suggest employing a Cross-Layer Multi-Perception Neural Network (CLMPNN) for hyperspectral sensory image feature observation in order to determine the optimal assessment of peanut maturity in agriculture. The sensing unit first determines the angular cascade projection’s (ACP) structural dependencies for the peanut pod structure. With the aid of color-intensive saturation, the entity projection of pod growth is found using the Slicing Fragment Segmentation (SFS) technique. This generates the various entity variations by integrating relational maturity and non-maturity findings with spectral values. Next, cross-layer multi-perception neural networks are trained with hyperspectral values optimized by LSTM to distinguish between mature and immature pods. In comparison to the other system, this one does exceptionally well in precision agriculture, with a 98.6 well recall rate, a 97.3% classification accuracy, and a 98.9% production accuracy.

PHENOLOGY AND HARVEST POINTS OF SNAP BEAN VARIETIES RELATED TO DEGREE DAYS ACCUMULATION

The objective of this study was to characterize the phenology and determine the harvest points of snap bean varieties related to degree-day accumulation. The experiments were conducted in the Teaching Garden of the Federal University of Ceará, evaluating five bean genotypes. A randomized block design with three and five replications was used for experiments 1 and 2, respectively. Each experimental unit consisted of a 9.6 m seedbed. In the first experiment, the spacing adopted was 0.1 x 0.4 m (24 plants per plot). For the second experiment, the spacing adopted was 0.1 x 0.3 m (32 plants per plot). Phenological characterization was carried out, estimating the thermal requirement and the pod growth curve. The evaluated genotypes presented thermal requirements ranging between 1,282 and 2,111 °C per day. The Habichuela genotype presented shorter cycle length, lower degree-day accumulation and higher initial pod growth compared to the others. It is recommended to harvest Feijão Vagem do Panamá (FVP), Habichuela and De Metro between the 10th and 15th day after fruiting. For Pronto Alívio and Quiura Bejuco, the harvest should be conducted at the 20th day after fruiting.

Pod Production Dynamics and Pod Size Distribution of Theobroma cacao L. Clone CCN 51 in Full Sunlight

Cacao fruit production dynamics vary from one location to another and are conditioned by the number of pods produced per tree. During cocoa pod development, the strength of the carbon sink varies depending on the demand exerted by the pods, which is proportional to the size. The relationship between cocoa pod production dynamics and size distribution is still poorly understood. Dissecting this relationship is an important step toward further improving cocoa crop management. In this study, the annual yield dynamics and quantity of cocoa pods produced by popular, highly productive, and widespread clone CCN 51 were investigated, based on six size classes observed during its fructification. Growth parameters were determined as weekly increments of pod length and diameter, whereas daily increments were estimated using the logistic Richards model. The fruiting cycle was characterized by the coexistence of fruits of various sizes where the number of pods belonging to each size class changes throughout the fruiting season. Fruit production varied following a seasonal pattern, reaching a maximum of 36 pods/tree, in trees cultivated in full sunlight, of which approximately 55% matured and were harvested. The peak carbon sink demand occurs when the tree pods have the highest numbers of pods. During this period, 65% of the pods had lengths between 5 and 15 cm, which corresponds to the period of the highest pod growth rate. The average length values of the harvested pods were generally below 23 cm and rarely exceeded 7 pods/tree. The Richard model proved to describe accurately the pod growth rates for CCN 51. This represents a promising tool to determine pod growth in other cultivars of relevance for the cocoa industry, which is essential to improve cocoa crop management.

The effect of nitrogen, sulfur and silicate fertilizer application on growth, yield, and biochemical content of vegetable soybean pod (Glycine max L. Merr.)

Optimized fertilizer management, focusing on nitrogen, sulfur, and silica, plays a crucial role in agriculture production. This study aimed to investigate the effects of administering sulfur and silica on the growth, production yield, and biochemical contents of vegetable soybean. The investigation was conducted in factorial randomized block design with two factors and three replications. The first factor was the nitrogen (46% N) fertilizer dosage (N1 = 50 kg/ha and N2 = 100 kg/ha), while the second variable was the dosage with the following sulfur-silica soluble compound (2.3% S – 10% Si) fertilizer ratios (P0 = 0 ml/L (control), P1 = 1 ml/L (23 mg/L S and 100 mg/L Si), P2 = 1.33 ml/L (30,7 mg/L S and 133 mg/L Si), and P3 = 2 ml/L (46 mg/L S and 200 mg/L Si). The results indicated that applying 2 ml/L S-Si fertilizer along with 100 kg/ha of nitrogen can lead to the most favorable results in number of branches, number of leaves, number of pods, pod weight per plant, weight of 100 seeds and plant biomass weight. The fertilizer dose comprising of 50 kg/ha of N and 9.2-40 mg/plant of S-Si clearly demonstrated the highest protein content, measuring 110.6 mg/g. S-Si fertilizer dosages, exhibiting a linear escalation in the 11S/7S globulin ratio within vegetable soybean seeds. The peak 11S/7S ratio was observed in the treatment of 100 kg/ha of N - 2 ml/L of S-Si. The study results indicate that a combination of nitrogen fertilizer and sulfur-silicon yields the best vegetable soybean pod yield, improving soybean protein nutritional quality. Therefore, sulfur and silica treatments should be standardized in vegetable soybean management

Assessing Foliar Fungicides for Soybean Disease Management and Yield in Indiana

Foliar diseases can significantly impact soybeans in Indiana, and fungicides can be an effective management tool to protect yield against disease. Fourteen foliar fungicide products were evaluated for efficacy on soybean foliar diseases and yield in 10 field trials from 2019 to 2021 in Indiana. Fungicides were applied at their recommended rates in a single application at the beginning pod (R3) growth stage. Cercospora leaf blight ( Cercospora spp.), brown spot ( Septoria glycines Hemmi), and frogeye leaf spot ( Cercospora sojina Hara) were the most prominent foliar diseases observed in the trials. Under low to moderate Cercospora leaf blight disease pressure, there were no significant differences between foliar fungicides and the nontreated control averaged across all site-years. In contrast, all foliar fungicides significantly suppressed brown spot from 69 to 92% relative to the nontreated control. Only bixafen + flutriafol and azoxystrobin + pydiflumetofen + propiconazole significantly suppressed frogeye leaf spot severity over the nontreated control. Foliar fungicide applications did not significantly increase yield over the nontreated control across all site-years. Therefore, under low to moderate foliar disease risk, fungicide applications may not be warranted in Indiana. Growers should continue to scout soybean fields prior to the beginning pod (R3) growth stage, then make an informed, sustainable decision to use a fungicide for disease management.

Influence of naphthalene acetic acid on aborted okra growth, bioactive compound and minerals

The study was conducted to evaluate the effect of different concentrations of NAA (naphthalene acetic acid) on seedless okra production, vitamin C, carotenoids, flavonoids, antioxidants (DPPH), phenolic, and mineral content. The micro-syringe injection in flower stigma was an innovative method of application and was used in this experiment rather than spray as a common and traditional method. The flower stigma injection method was applied on the flower stigma after the anthesis of the flower of the okra plant using NAA at different concentrations. The lowest concentration (25 mg/l) of NAA greatly increased the pod setting compared to the higher concentrations and control. NAA application at 25 and 50 mg/l concentrations induced higher values of pod length, diameter, size, weight, ascorbic acid (vitamin C), and soluble solid content over the control. The chlorophyll content in leaves was affected significantly by different concentrations of NAA. It was found that 25 and 50 mg/l concentrations of NAA significantly increased chlorophyll content, fiber, moisture, flavonoid, carotenoid, antioxidant (DPPH), minerals and phenolic content compared to the other concentrations and control. In addition to that control and 25 mg/l concentrations of NAA, had increased the production of healthy seeds compared to the 50 and 100 mg/l. Moreover, 50 and 100mg/l of concentrations showed higher aborted seed (seedless) than the other concentration and control. Therefore, it seems that 25 mg/l is the best concentration for pod growth and development as well as 100mg/l is the best for seedless okra production.

Effects of fertilizer application on cacao pod development, pod nutrient content and yield

Fertilizer application in cacao production systems in West Africa yields highly variable results, ranging from no effect to doubling of the yield. Mechanisms underlying yield responses to increased nutrient availability are still largely unkown. In this study, we assessed how fertilizer application affects pod development and production of cacao trees in a full sun cocoa system in Côte d'Ivoire and a shaded cocoa system in Ghana. We monitored pod growth over time and the number of pods produced simultaneously on the trees in the minor and major harvest seasons. Furthermore, we measured nutrient concentrations in cherelles and beans and husks of developing pods in the major harvest season to estimate the total nutrients allocated to developing pods per tree. Lastly, we performed detailed yield measurements (number of pods, location in the tree (canopy or trunk), pod size and bean content) in 2020 for the plot in Côte d'Ivoire.Our results showed that, in the major harvest season, pods on fertilized trees grew wider (average: 15.4 cm) than pods on unfertilized trees (average: 11.9 cm). A higher pod growth rate resulted in a larger final pod size; larger pods took longer to mature. In the major harvest season, more cherelles on fertilized trees than on unfertilized trees reached maturity despite having an equal or lower nutrient content. Competition for assimilates rather than nutrients seems to induce cherelle wilt. In pods past wilting stage, fertilizer application slightly influenced nutrient dynamics of developing pods but not the final nutrient content in ripe pods. Lastly, increased nutrient availaibility did not change the absolute number of pods a tree produced annually. However, fertilizer application did increase the estimated annual dry bean yields from 2260 kg ha−1 to 2930 kg ha−1 by increasing the number of pods that developed during the major harvest season, when pods were heavier and the bean weight within the pods was relatively higher.

High plant density increases sunlight interception and yield of direct-seeded winter canola in China

Summary Rationally higher population density is crucial for seeking a balance that meets lodging resistance and maximizes seed yield in mechanized direct-seeded winter canola. In this study, a split-plot experiment with two cultivars (Huayouza9 and Zhongshuang11) and eleven planting densities (12–105 plants m-2) was conducted in a two-season field experiment to evaluate the high planting density in this cropping system and improve its production efficiency. Seed yield noticeably increased in planting density up to 80 plants m-2 in Zhongshuang11 (2187 kg hm-2) and 60 plants m-2 in Huayouza9 (2943 kg hm-2). The seed yield of Huayouza9 did not differ significantly from the local target seed yield. Higher plant density curtailed the luxurious vegetative growth of individual canola plants at the density of no less than 60–80 plants m-2, and high seed yield was derived from the increased ratio of main raceme and branch seed weight in winter canola. An increase in plant densities contributed to the reinforced sunlight interception at the pod-filling stage, providing a larger canopy photosynthetic area for the rapid growth of more canola pods at higher densities (60–105 plants m-2). Lodging resistance and breaking resistance decreased sharply with the plant density increasing from 12 to 60 plants m-2 while remaining almost steady as it further increased from 60 to 105 plants m-2 for Huayouza9 and Zhongshuang11. Hence, the population density of 60 plants m-2 reached a balance between lodging resistance and maximized seed yield in mechanized direct-seeded winter canola in China.

Mathematical Modeling To Estimate The Growth Of Guandu Bean Pods And Seeds

The objective of this study was to adjust mathematical equations that accurately and non-destructively estimate the growth of pods and seeds of pigeon pea cultivar Fava Larga from the average length and width. For this, the maximum width (W), maximum length (L), and observed mass (OM) of pods and seeds were measured. Linear models of the first degree, quadratic, power, and exponential were adjusted based on the value of 400 pods and 1938 seeds, in which the OM was used as a dependent variable as a function of L and W as independent variables. For the validation of the models, the root means square of the error was calculated from all equations. Thus, in the estimation of the growth in mg of the pods and seeds of the 'Fava Larga' pigeon pea, the quadratic model equations represented by and , respectively, obtained using the width.

Morphological and molecular insights of calcium in peanut pod development

Calcium is an important secondary macronutrient after nitrogen, phosphorus and potassium for the proper development of the plant. It is typically important for the formation of cell walls, cell members and accumulates in the plant cells. Calcium deficiency occurs rarely in nature but excess calcium limits plant communities on calcareous soils. In peanut, calcium uptake by plants from the soil will remain in the plant tissues and will not be transported back to developing pods where calcium requirement is more. The geotropic growth of peanut pods had capacity of absorption of calcium from the soil for filling and development of pods. Application of calcium before the pod development stage in peanut is required to have sufficient calcium available to the pods which could help an increase in yield up to 20–30%. The calcium-related genes in different metabolic pathways help in the regulation of embryo abortion in peanut and also a well-documented role in mediating plant responses to abiotic and biotic stimuli. This article provides a summary of the role of calcium, its management details, the transport of calcium into plants through the soil and overview of calcium genes in peanut pod development.

The Value Chain of Moringa oleifera Plant and the Process of Producing Its Biodiesel in Ghana.

Moringa oleifera grows well in different parts of Africa, including Ghana, and throughout the world as it can tolerate moderate cold and severe drought. Dubbed as the “Miracle Tree,” Moringa has a number of nutritional, pharmaceutical, and cosmetic applications. It is also used as a cure for diabetes and various forms of cancer. Another promising use of this plant is the production of biodiesel. However, such application demands vast cultivation areas and this can lead to competition with the cultivation of crops for food, forestry, and environmental protection. Furthermore, it requires suitable cultivation schedules that favor the growth of pods containing oil-rich seeds. The present work investigates the availability of land for Moringa cultivation in Ghana to increase the energy production from the plant. The study reports on an overview of the soil, water, and climatic conditions that favor Moringa oleifera cultivation and oil production, the conversion of Moringa oleifera oil to biodiesel, and the performance of Moringa oleifera biodiesel versus mineral diesel as well as the commercial enhancement of the Moringa product.

A Note on the Development of an In-Tube Growth System to Study Pod-specific Responses of Peanut (Arachis hypogaea)

As a geocarpic plant, the fruits of peanut are matured below ground. Developing pods share a similar nutritional and microbial environment as roots, albeit they have distinct physiology and responses to environmental stimuli. Separating pods and roots into different environments to study a pod-specific or a root specific response to stimuli is still technically challenging. Research was conducted to develop an easy and affordable system to support the growth of individual pods in a controlled environment that is separate from roots, named the In-Tube Growth (ITG) system. The data indicate that the growth of pods of various varieties in ITG is comparable to those in open soil. The ITG system was used to investigate the defects caused by calcium deficiency in the geocarposphere, demonstrating it as a useful system for studying pod development and their responses to biotic or abiotic stresses.

Variety and Seeding Time Influence on Flowering Characteristics and Trichodesmine Content in Sunn Hemp (Crotalaria juncea L.)

Background: Sunn hemp (Crotalaria juncea L.) is an important annual legume used as green manure. It contains pyrrolizidine alkaloids, which are apparently effective in suppressing nematodes. It is pertinent to know the growth stage during which pyrrolizidine alkaloid concentrations become higher. Methods: The period of days necessary for flowering, pod growth and the concentrations of one pyrrolizidine alkaloid in pods at different stages in five sunn hemp cultivars with May and July seeding were investigated. Result: Findings indicated that flowering of the two cultivars occurred later than the others, especially for May seeding. The pods grew to 20 mm length in 6-11 days from flowering. Then the pods grew to maximum size (40 mm length) in only few days. A main pyrrolizidine alkaloid in sunn hemp seed, trichodesmine, increases as pod size grow; then it increases considerably as pod mature. However, it in matured pod hull contains similar values of whole immature pod. These results demonstrate that both day-neutral and short-day cultivars with July seeding shorten the days to first flower and indicate that cutting after 10 days from first flowering is effective for increasing pyrrolizidine alkaloid concentration.

Assaying the efficiency of sulfate, chelate and zinc nanoparticle fertilizers in green bean grown in alkaline soil

The excessive fertilizer application is a recurring problem in agriculture as it not only harms the soil texture but also diminishes the micronutrient availability i.e., zinc (Zn). Zn is an essential element for crop production and quality, and is also indispensable for human diet. Zn deficiency is a common problem in alkaline soils. This study aims to assess the efficiency of three different Zn fertilizers in Phaseolus vulgaris plants, grown in an alkaline soil. P. vulgaris plants were grown in an experimental greenhouse under four different treatments: control (no Zn fertilization), ZnSO4, the chelate diethylenetriaminepentaacetic acid (DTPA-Zn), and Zn nanoparticles (NfsZnO). Each Zn source was applied at three different doses (0, 25, 50, 100 mg kg−1). Parameters related to biomass, photosynthetic pigments, and Zn accumulation were analyzed. Zn sources enhanced bean pod growth and yield. Furthermore, the three Zn sources increased Zn accumulation in all plant organs, except in leaves. Whereas, plants supplied with 100 mg kg−1 of DTPA-Zn and 25 mg kg−1 of NfsZnO accumulated the highest bean Zn concentration. Generally, plants supplied with DTPA-Zn and NfsZnO showed the highest Zn content values. Besides, Zn sources enhanced the values of Zn efficiency parameters in a dose-dependent manner. According to the results, the three Zn fertilizers were effective to increase the parameters analyzed in P. vulgaris. However, DTPA-Zn and NfsZnO were more effective to enhance yield and bean Zn content, and thus can be useful for bean cultivation in alkaline soils.

Foliar Spray with Pepsin-and Papain-Whey Protein Hydrolysates Promotes the Productivity of Pea Plants Cultivated in Clay Loam Soil.

Papain and pepsin-hydrolyzed whey protein (PAH and PEH, respectively) were prepared and characterized for its degree of hydrolysis, chemical constituents (amino acid and peptides) and antioxidant activity. A field experiment was conducted at El Salheya El Gedida City, Sharqia, Egypt, during the seasons 2019 and 2020, to investigate the biological action of the foliar spray of PAH and PEH on the growth and yield of pea plants cultivated in a clay loam soil. Foliar application of the papain and pepsin-hydrolyzed whey protein (PAH and PEH, respectively) at 1000 and 2000 mg/L was applied three times after 25, 35 and 45 days from planting. All protein foliar spray treatments had significant positive effects on the uptake of N, P and K, simultaneously increasing the contents of all the photosynthetic pigments (Chlorophyll a, Chlorophyll b and Carotenoids) in a concentration-dependent manner. The most conspicuous increase was seen in Chlorophyll b (105% increase), followed by Carotenoids (91% increase). Generally, the favorable increases caused by the second level of application (2000 mg/L) were nearly 2–3 times that of the low level (1000 mg/L). Pod growth and formation indicators, e.g., no. of pod/plant, pod length and no. of seeds/pod, responded more evidently to the hydrolyzed than the intact form of whey protein treatments. Hydrolyzed whey protein foliar spray treatments achieved significantly higher increases in the global field yield components of Pisum sativum plants than the intact form, where peptic hydrolysates were significantly superior to papain hydrolysate. The treatment PEH (2000 mg/L) can be recommended as the most effective bio-stimulating foliar spray treatment for higher plant productivity when applied 25, 35 and 45 days after planting.

Oilseed rape (Brassica napus L.) pod shatter resistance and its relationship with whole plant and pod characteristics

Low pod resistance is a main reason for high oilseed rape loss in mechanized harvesting. To select varieties with high resistance, this study proposed a 2-degree-of-freedom collision method (2-DFCM) for pods. It was compared with the available ripping and shaker collision methods. The influences of various factors on pod resistance were discussed, and the characteristics of the pods of whole plants were compared and analysed. The results demonstrated that the 2-DFCM results are more reliable based on pod resistance. Field pod resistances were found to be significantly lower than after the indoor equilibration of unripe plants to the same water content, and 2-DFCM is convenient for field testing and accurately identifies pod characteristics. The pericarp, thousand-seed weight, pod thickness and volume, and plant branch height were found to be significantly correlated with pod resistance, which can be strengthened by breeding. The varieties and pod growth positions significantly affected resistance. For field pods, the branch pod resistance was significantly higher than that of the main inflorescence, and the top pod of the raceme had the lowest resistance. The results of this paper provide a reliable reference for agronomic experts to improve oilseed rape varieties.

Chicken feather waste-derived protein hydrolysate as a potential biostimulant for cultivation of mung beans

Feathers, a waste product of poultry industries have highly recalcitrant structure and are a rich source of organic nitrogen. The use of keratinolytic microbes for bioconversion of feather waste to a value added hydrolysate is gaining the interest of researchers. Bacillus aerius NSMk2 has been reported as a potential keratinolytic strain that converts chicken feather waste into a hydrolysate rich in proteins, small peptides and amino acids. In the present study, biostimulating potential of chicken feather waste-derived protein hydrolysate (PH) generated by biocatalytic action of Bacillus aerius NSMk2 has been evaluated for the growth of mung beans (Vigna radiata), under potted conditions. Soil treated with PH, unhydrolyzed feathers (UF) or diammonium phosphate (DAP) was transferred to different pots, and seeds of mung beans were transplanted. PH treated groups showed superior germination frequency and early growth of pods. The highest number of pods with highest weight of seeds was observed in test groups as compared to control. Higher weight of roots was observed in plants treated with PH, and content of deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and total protein was found to be high. The content of phosphate, potassium and carbon:nitrogen ratio (C:N) was substantially high in soil after application of hydrolysate. Appreciable count of free living nitrogen fixers and phosphate solubilizers was also observed in PH treated groups. The present study shows improved plant performance, yield and soil fertility after application of Bacillus aerius NSMk2 derived protein hydrolysate, and therefore indicates its application as a potential biostimulant in agroindustry.

Lima Bean Growth, Leaf Stomatal and Nonstomatal Limitations to Photosynthesis, and 13C Discrimination in Response to Saline Irrigation

Soil salinization is a widespread problem severely impacting crop production. Understanding how salt stress affects growth-controlling photosynthetic performance is essential for improving crop salt tolerance and alleviating the salt impact. Lima bean (Phaseolus lunatus) is an important crop, but little information is available on its growth and leaf gas exchange in relation to a wide range of salinity. In this study, the responses of leaf gas exchange and whole plant growth of lima bean (cv. Fordhook 242) to six salinities with electrical conductivity (EC) of 2.9 (control), 5.7, 7.8, 10.0, 13.0, and 15.5 dS·m−1 in irrigation waters were assessed. Significant linear reduction by increasing salinity was observed on plant biomass, bean yield, and leaf net carbon assimilation rate (A). As EC increased from the control to 15.5 dS·m−1, plant biomass and A decreased by 87% and 69%, respectively, at the vegetative growth stage, and by 96% and 83%, respectively, at the pod growth stage, and bean yield decreased by 98%. Judged by the linear relations, the reduction in A accounted for a large portion of the growth reduction and bean yield loss. Salinity also had a significantly negative and linear effect on leaf stomatal conductance (gS). Leaf intercellular CO2 concentration (Ci) and leaf C13 isotope discrimination (Δ13) declined in parallel significantly with increasing salinity. The A-Ci curve analysis revealed that stomatal limitation [Lg (percent)] to A increased significantly and linearly, from 18% to 78% and from 22% to 87% at the vegetative and pod-filling stages, respectively, as EC increased from the control to the highest level. Thus, relatively nonstomatal or biochemical limitation [Lm (percent), Lm = 100 − Lg] to A responded negatively to increasing salinity. This result is coincident with the observed Δ13 salt-response trend. Furthermore, leaf carboxylation efficiency and CO2-saturated photosynthetic capacity [maximum A (Amax)] were unaffected by increasing salinity. Our results strongly indicate that the reduction in lima bean A by salt stress was mainly due to stomatal limitation and biochemical properties for photosynthesis might not be impaired. Because stomatal limitation reduces A exactly from lowering CO2 availability to leaves, increasing CO2 supply with an elevated CO2 concentration may raise A of the salt-stressed lima bean leaves and alleviate the salt impact. This is supported by our finding that the external CO2 concentration for 50% of Amax increased significantly and linearly with increasing salinity at the both growth stages. Leaf water use efficiency showed an increasing trend and no evident decline in leaf chlorophyll soil plant analysis development (SPAD) readings was observed as salinity increased.