Yellow Pod Research Articles

Using Stochastic Petri Nets for Reliability Evaluation of Subsea Annular BOP

This paper performs reliability evaluation of the subsea annular blowout preventer (BOP) based on stochastic Petri nets. The presented model has been analyzed based on its isomorphic continuous time Markov chain. According to the derived equations, transient availability, reliability and MTTF of the annular BOP are obtained. Availability will reach a stable value very quickly while reliability decreases slowly over time. The effects of failure rates on MTTF are researched. The results demonstrate that in order to effectively improve MTTF, great efforts should be made to reduce the failure rates of blue pod or yellow pod.

Determinação do estádio de dessecação em soja de hábito de crescimento indeterminado no Mato Grosso

For cultivars with indeterminate habit, there are no reports of the most appropriate period to conducted burndown in pre-harvest. The study aimed to evaluate the influence of burndown on three different times over physiological and sanitary quality of seeds and agronomic characteristics of SYN-9074 RR cultivar with indeterminate habit, in three areas simultaneously. It was used a randomized complete block design with four replications, and joint analysis were conducted for the three distinct areas. Treatments refer to the application period of diquat (0.3 kg ha -1 ), or better, in soybean plants at maturation stages R6.5 (fully formed seeds, pods 50% yellow and 50% green), R7 (pods 70% yellow, with a fully mature pod on the main stem) and R7.5 (90% yellow pods) and a check without herbicide. Germination test, dry mass of dossel and little root part, shoot length and little root, sanitary condition and mass of 1000 seeds and yield were evaluated. The period more adequate to accomplish burndown in pre harvest of SYN-9074 RR cultivar with indeterminate habit was with plants showing 90% of yellow pods, or maturation period R7.5, that provided higher yield and lower incidence index of Phoma sp., Colletotrichum dematium var. truncata and Fusarium sp. fungi.

Genetic relationship of cowpea (Vigna unguiculata) varieties from Senegal based on SSR markers

Genetic diversity and phylogenetic relationships among 22 local cowpea (Vigna unguiculata) varieties and inbred lines collected throughout Senegal were evaluated using simple sequence repeat molecular markers. A set of 49 primer combinations were developed from cowpea genomic/expressed sequence tags and evaluated for their ability to detect polymorphisms among the various cowpea genotypes. Forty-four primer combinations detected polymorphisms, with the remaining five primer sets failing to yield PCR amplification products. From one to 16 alleles were found among the informative primer combinations; their frequencies ranged from 0.60 to 0.95 (mean = 0.79). The genetic diversity of the sample varied from 0.08 to 0.42 (mean = 0.28). The polymorphic information content ranged from 0.08 to 0.33 (mean = 0.23). The local varieties clustered in the same group, except 53-3, 58-53, and 58-57; while Ndoute yellow pods, Ndoute violet pods and Baye Ngagne were in the second group. The photosensitive varieties (Ndoute yellow pods and Ndoute violet pods) were closely clustered in the second group and so were inbred line Mouride and local cultivar 58-57, which is also one of the parents for inbred line Mouride. These molecular markers could be used for selection and identification of elite varieties for cowpea improvement and germplasm management in Senegal.

Sowing date as a factor determining French bean yield for processing

Abstract Field studies were conducted in the years 2003-2005 in the Experimental Farm of the University of Life Sciences in Lublin. Beans from four cultivars - ‘Paulista’ and ‘Hit’ (green pods) and ‘Korona’ and ‘Galopka’ (yellow pods) - were grown on fawn soil, formed of loess deposits, on chalky marls, containing 1.4% organic substances on average. There were six sowing terms, every 6-7 days starting from the middle of May to the end of June. French bean harvest was performed once, when about 75% of the pods on the plants were in the phase of technological maturity, which fell between the third ten days of July and the first ten days of September. From the plot and plant the number and yield of the pods were determined: total, marketable and non-marketable small pods, unshapely and overripe pods, as well as those with symptoms of disease. The highest total and marketable pod yields - on average, 15.45 and 11.06 t ha-1, respectively - were obtained from plants sown in the first ten days of June, whereas the lowest - 12.54 and 9.54 t ha-1 - were from those sown in the middle of May. As a result of performing a one-time French bean pod harvest, the share of non-marketable pod yield in the total yield was on a similar level (24-28%), depending on the growing term. Variability was demonstrated in the share of particular non-marketable yield fractions (small pods, undersized, unshapely, and overripe pods, as well as those with disease symptoms), depending on the sowing date. Growing four French bean cultivars from sowing in the period from the middle of May to the end of June allowed us to extend the period of fresh pod harvest to six or seven weeks.

EFFECT OF MATURITY STAGES FOR WINTER- AND SPRING-SOWN CHICKPEA (CICER ARIETINUM L.) ON SEED MINERAL CONTENT

Two-year field experiments were conducted to study the effect of two planting dates and seed maturity on mineral content of chickpea seeds. In 2003 and 2004, chickpea ‘Jubiha-2’ seeds were planted in late December (winter-sown) and early March (spring-sown). For both planting dates, pods were harvested at five maturity stages: 1) beginning of seed fill (BS), 2) full-size seed (FS), 3) greenish-yellow pod (GY), 4) yellow pod (Y), and 5) brown pod (B). The concentrations of nitrogen (N), potassium (K), phosphorus (P), magnesium (Mg), calcium (Ca), and zinc (Zn) on a dry weight basis significantly decreased as the seeds developed from the BS to the FS stage, then did not change significantly at the Y and B stages. Nutrient content (mg seed−1) increased as the seed dry weight increased. Seeds from spring-sown plants had higher concentrations of N and manganese (Mn) than winter-sown plants. The maximum mineral content of chickpea was achieved at seed physiological maturity.

Effect of Growth Stage and Pod Position on Soybean Seed Isoflavone Concentration

Field experiments were established during 2004 at two sites of the Emile A. Lods Agronomy Research Centre in Sainte-Anne-de-Bellevue, QC, Canada. Soil types were a fine sandy loam at one site (site A), and a Macdonald clay loam at the other (site B). During seed development and maturation, three replicates of 200 pods were collected from different parts of plants (from the top and base of plants) at three development stages; full-seed pod (R6), yellow pod (R7), and brown pod (R8), resulting in 6 treatments. Total and individual isoflavone concentrations were determined by high-performance liquid chromatography. Our results indicate that the individual and total isoflavone contents were influenced significantly by growth stage and pod position. The maximum individual and total isoflavone contents were recorded when the soybean seeds were collected from the base parts of plants at brown pod stage (R8). The maximum protein content of 468 g kg-1 was obtained by collecting soybean seeds at the earlier growth stage (R6). Also, the soybean seeds developing at the top parts of plants accumulate greater amount of protein than those from base region. On the other hand, soybean seeds developing at the base parts of plants (first 20 cm from soil surface) accumulate greater amount of oil than those from the top (last 20 cm from soil surface).

Pre-harvest infestation of beans ( Phaseolus vulgaris L.) by Acanthoscelides obtectus Say (Coleoptera: Bruchidae) in relation to bean pod maturity and pod aperture

Acanthoscelides obtectus is a bruchid beetle that oviposits into ripening bean pods in the field. More precise data are needed for developing management strategies for small-scale farmers in East Africa. In farmers' fields, an infestation rate of 6.9% infested bean seeds was recorded in dry pods, but in wilting yellow pods there was a lower infestation of 2.5%. No wilting green pod had been infested. After releasing 680 bruchids in an open field, the infestation rate in dry pods increased to 39 and 7% in wilting yellow pods, but again no wilting green pod was found to be infested. In no-choice laboratory trials, however, A. obtectus infests wilting pods; and pod aperture did not influence infestation rates. Stimulants for oviposition were evaluated in no-choice trials. Bean pods containing seeds were as attractive as bean seeds alone, and significantly more attractive as empty opened bean pods. Bean pods without seeds were more attractive than the empty control. The natural infestation rate in fields close to homesteads was higher than in fields more than 1 km away from any habitation. Farmers are advised to be aware of the infestation danger in the field, and to consider early harvest if they have infestation-free storage.

Yield Potential Evaluation in Chickpea Genotypes under Late Terminal Drought in Relation to the Length of Reproductive Stage

Chickpea grown in the semiarid Mediterranean environments of West Asia and North Africa may experience an extended late-drought stress. The objective of this experiment was to evaluate seed dry weight accumulation, reproductive growth duration, and seed yield in five chickpea genotypes in order to identify those under drought stress. Chickpea plants were exposed to two irrigation treatments (from flowering to seed physiological maturity): 1) Irrigation; 2) non-irrigation (rainfed) treatment. Seed dry weight and moisture content, seed yield and yield components, and reproductive growth duration [as defined from flowering to physiological maturity (yellow pods)] were measured. Seeds from plants grown under non-irrigation (rainfed) treatment reached their maximum dry weight and minimum seed moisture content earlier than those from plants grown under irrigation treatment, indicating that chickpea had shorter reproductive growth duration and faster maturity under late-terminal drought (rainfed). The non-irrigation treatment decreased seed yield by 49-54% as compared with the irrigation, except for Flip 97-99 (10% reduction only). Seed yield was positively correlated with reproductive growth duration. The genotype DZ 10-11 had the highest reproductive growth duration and seed yield under irrigation. Late drought stress (non-irrigation) was detrimental to all genotypes. To maximize seed yield of chickpea, late-terminal drought stress should be avoided.

Chemical Composition and Mineral Content of Common Vetch Seeds during Maturation

ABSTRACT Common vetch (Vicia sativa L.) is an important legume cultivated for feed grain and forage in the Mediterranean and Central Asia regions. Little information is available about the changes in seed mass, chemical composition, and mineral concentration in the developing seeds of common vetch. Therefore, the objective of this experiment was to study the changes in seed mass, moisture content, fat, fiber, proteins, carbohydrates, reducing sugars, and macro- and microelements in common vetch seeds sampled at four pod developmental stages described based on pod color. Common vetch pods were harvested at four pod developmental stages: 1) full-size seed (FS), 2) greenish-yellow pods (GY), 3) yellow pods (Y), and 4) brown pods (B). Common vetch seeds attained maximum mass accumulation when pod color turned to yellow (the Y stage), which was a good indication of seed physiological maturity in common vetch. Results showed that ash, fat, fiber, protein, and carbohydrate content increased between the FS and GY stage. There was no significant change in the accumulation of these components at the Y stage as compared with the GY stage. During the desiccation phase (the Y to B stage), there was an increase in carbohydrate and reducing sugars and a decrease in proteins. Seed content (μg seed−1) of macro- and microelements levels increased as the seed matured, reaching the maximum level by the GY stage [for phosphorus (P), sodium (Na), zinc (Zn), and manganese (Mn)], the Y stage [for copper (Cu)], and the B stage [for potassium (K) and iron (Fe)]. These results suggest that the majority of seed chemical composition was accumulated by the GY stage where farmers can harvest common vetch seed without reducing seed mass and nutrient loss. These data serve as a useful characterization of changes in chemical composition based on pod developmental stages for further studies.

Slow drying improved desiccation tolerance of immature seeds of common vetch

Drying common vetch seeds in the intact pods improved their desiccation tolerance and germination, this may be due to a slower rate of seed moisture loss or additional gain of dry weight of the seeds. Little information is available on the effect of slow drying on the desiccation tolerance of immature seeds of common vetch. The objective of this experiment was to study the effect of seed incubation at 100% relative humidity for 48 h on the rate of moisture loss and germination of common vetch seeds harvested at different maturity stages. Seeds were harvested at five pod developmental stages; 1) beginning seed fill (BS), 2) full-size seed (FS), greenishyellow, 4) yellow pod and 5) brown pod. Harvested seeds were subjected to two drying methods; either dried under ambient condition or by incubating the seeds at 100% relative humidity for 48 h prior to drying under the ambient condition. Incubating the seeds at 100% RH reduced the rate of seed moisture loss and enhanced the germination of the immature seeds (the FS and GY stages). These results emphasized the importance of the slow drying for enhancing seed desiccation tolerance during seed development and maturation of common vetch, demonstrating that the germination ability of common vetch was independent of seed mass and maturation.

Effect of air‐drying immature seeds in harvested pods on seed quality of common vetch (Vicia sativa L.)

Immature seeds of common vetch had low germination and were desiccation sensitive when seeds were extracted from pods before drying. Air‐drying immature seeds in harvested pods may improve their germination and vigour. The objective of this experiment was to study the effect of air‐drying immature seeds in harvested pods on seed germination and vigour of common vetch and to identify the vigour test that best discriminates seed vigour differences amongst seeds harvested at different maturity stages and drying treatments. Seeds of common vetch were harvested at five pod developmental stages: beginning of seed fill (BS), full‐size seed (FS), greenish‐yellow pod (GY), yellow pod (Y), and brown pod (B) and subjected to three drying treatments: seeds dried after extraction from pods (depodded), dried in pods detached from plants (podded detached) or attached to plants (podded attached). Seed germination and seed vigour, as estimated by the germination after three accelerated ageing (AA) treatments and by electrical conductivity of seed leachate, were evaluated for the harvested seeds. Seeds were subjected to three ageing treatments (100% RH and 39°C for 72 h, 39°C for 96 h, or 45°C for 48 h) to identify the AA treatment that best discriminates seed vigour differences amongst common vetch seed lots. Podded dried seeds detached from or attached to plants had higher standard germination, germination after three accelerated ageing treatments, and lower electrical conductivity of seed leachates than depodded dried seeds when seeds were harvested at the BS and FS stages of development. Although the podded dried immature seeds did not differ significantly in standard germination from the podded dried mature seeds, the podded dried immature seeds had lower vigour as estimated by the germination after 39°C for 96 h. Seed ageing at close to 100% relative humidity and 39°C for 96 h was the best condition to separate the differences in vigour among maturity stages and drying treatments. The 39°C for 96 h treatment can be a useful test to assess seed vigour of common vetch and needs further evaluation.

Effect of maturity stage on germination and dormancy of fresh and air‐dried seeds of bitter vetch (Vicia ervilia L.)

Bitter vetch is an important legume crop cultivated for forage and seed yield in the Mediterranean, West Asia, and North Africa regions. Delaying seed harvest of bitter vetch may increase seed losses due to pod shattering; however, early harvest may influence seed dormancy and the ability of seed to germinate. Field experiments were conducted at two locations in Jordan to study the effect of maturity stage on germination and dormancy of fresh (before drying), air‐dried, and dry‐prechilled (at 5°C for 8 days) seeds of bitter vetch. Pods were harvested at three development stages: full‐seed pod (FS), yellow pod (YP), and brown pod (BP). Percentage of normal, abnormal, hard, and dead seeds at 14 days after planting in standard germination tests was recorded for the fresh, air‐dried, and dry‐prechilled seeds harvested at the three development stages. Germination counts of normal seedlings at 4, 7, 10, and 14 days after planting was used to calculate the germination rate index (GRI). For the fresh seeds, germination did not exceed 30% when seeds were harvested at the FS stage, and decreased to 0% at the YP stage. All non‐germinated fresh seeds harvested at the YP stage were dormant. Air‐drying and dry‐prechilling treatments improved seed germination at the YP and BP stages. Maximum germination was achieved in air‐dried and dry‐prechilled seeds harvested at the BP stage. The percentage of hard seeds was the highest for air‐dried seeds harvested at the FS stage. Percentage of hard and dormant seeds was decreased to the minimum when seeds were harvested at the BP stage and exposed to air‐drying and dry‐prechilling treatment before germination. Dry‐prechilled seeds had higher GRI than fresh and air‐dried seeds when seeds were harvested at the BP stage. In conclusion, maximum germination and minimum dormancy was achieved for air‐dried and dry‐prechilled seeds harvested at the BP stage. Dry‐prechilling treatment increased the speed of germination for seeds harvested at the BP stage. Presence of hard seeds reduced the germination of air‐dried seeds harvested at the YP stage. Bitter vetch seeds harvested at the YP stage may require scarification and a longer prechilling treatment to overcome seed dormancy observed at this stage.

Infection of Soybean with Soybean mosaic virus Increases Susceptibility to Phomopsis spp. Seed Infection

Infection of soybean [Glycine max (L.) Merr.] plants with Soybean mosaic virus (SMV) has been reported to enhance Phomopsis spp. seed infection, which reduces seed quality. The objective of this study was to determine the influence of SMV on Phomopsis spp. seed infection and seed germination and vigor. During 1995 to 1997, plants of two SMV‐susceptible cultivars (Clark and Williams) and their SMV‐resistant isolines (L78‐434 and L78‐379, resistant to SMV strains G1‐G6) were mechanically inoculated with SMV (G2 strain) at growth stages V4, V8 or R2, and Phomopsis spp. inocula were applied to all plants. Seeds harvested from SMV‐resistant isolines were consistently SMV free, whereas seeds from SMV‐inoculated susceptible cultivars accumulated SMV in seedcoats. Although environmental conditions were favorable, the incidence of Phomopsis spp. seed infection was consistently less than 12% in SMV‐resistant plants, and up to 14‐times greater in SMV‐inoculated susceptible plants, with primary infection occurring after seeds reached physiological maturity (at or after yellow pod stage). Seeds from SMV‐resistant isolines had high average standard germination (88%) and higher vigor (67% accelerated aging; 7 mS m−1 g−1 conductivity), whereas seeds from SMV‐inoculated susceptible cultivars had low standard germination (48%), low vigor (30% accelerated aging; 13 mS m−1 g−1 conductivity). Thus, infection by SMV at or before growth stage R2 increased the susceptibility of soybean seed to Phomopsis spp. infection, and resulted in poor seed quality and low vigor.

Determination of Peanut Maturity Using a Hunter Colorimeter

Abstract Peanut maturity has previously been correlated with the color of the mesocarp of the peanut hull going from light to dark as the peanut matures. In this study, peanuts were sorted into maturity classes of yellow, orange A, orange B, brown and black based on the hull scrape method of Williams and Drexler. The Hunter L*, a*, and b* values were also measured on the dry pods for each class. The color of the mesocarp of freshly harvested peanuts was determined using a Hunter colorimeter. Hunter L*, a*, and b* values on individual peanuts, representative of each class using wet and dry hulls, were reproducibly determined with standard deviations of less than 0.8%. Yellow peanut pods had a median L* value of 70.0, while mature black peanut pods had a median L* value of 51.7 and median values for orange A, orange B and brown pods were, 68.0, 63.7, 57.0, respectively. A similar inverse relationship was observed for the b* value and maturity, while the a* value reached a maximum at orange A. No correlation was observed between the peanut maturity and L*, a*, and b* values acquired with the exocarp intact. Hunter L* and b* values of mesocarps show potential for determining physiological maturity of peanuts.

`Venere' and `Alarico', New Scarlet Runner Bean (Phaseolus coccineus L.) Cultivars with Determinate Growth Habit

Runner bean cultivars grown in Italy are cross-pollinated climbing plants (2.5 to 3 m tall) that require hand-labor for staking and harvesting. They produce white and slightly reniform seeds (1.3 to 3.0 g) with flattened cotyledons. This kind of bean is called ‘Bianco di Spagna’ (Spanish White) in Italy. It is cultivated for the production of dry seeds or yellow pods containing seeds at the waxy stage. Both of these products can be used for processing or direct marketing. The development of determinate (bush) P. coccineus germplasm suitable for mechanical harvesting is an objective of a breeding project at the Experimental Institute for Vegetable Crops, Montanaso Lombardo, Milano, Italy (Campion and Servetti, 1991). ‘Venere’ and ‘Alarico’ are the first cultivars with a determinate growth habit developed in this program. The former was registered as a cultivar (Feb. 1994) in the Italian National Register of Varieties, which is under the control of the Ministry of Agriculture; the latter will be registered in 1996 in the same registry. Indeterminate (runner) and determinate types are adapted to hillside and mountainous areas in northern Italy at 300 to 1000 m. Such growing sites have light winds and moderate temperatures during summer (July to August), which permit good pod set. The presence of Hymenoptera, in particular bumblebees (Bombus spp.), is necessary for selfand cross-pollination. Crosspollination by these insects is 12.8% (Salamini and Uncini, 1971).

Optical Properties of the Pod Wall of the Pea ( Pisum sativum L.) II. Varietal Differences and Species Comparisons

Summary The transmission, reflection and absorption spectra of a range of legumes including Pisum sativum L. were compared. The optical properties of the pea pod appeared to be within the middle of the range of species studied. The optical properties of the pod walls of five different varieties of Pisum sativum were investigated at three stages of development. The highest transmission of Photosynthetically Active Radiation (PAR) was shown by a yellow pod (JI 73), followed by a parchmentless variety (JI 468). A purple variety (JI 60) showed a very low overall PAR transmission, while a thicker pod JI 149 transmitted less light than the conventional JI 141 pod, but more than the purple. Overall transmission tends to decrease as the pods become more fully developed, while reflection increases slightly in the older stages. The apparent Red/Far-red ratio of light entering the pod was calculated for each variety at each stage of development. Varieties which lack chlorophyll in the mesocarp or lack a sclerenchyma layer, and therefore transmit more light, have a higher ratio than conventional pods in which the seeds develop in a more shaded environment. The significance of these changes in relation to seed development is discussed, as well as the implications of slightly increased near-UV penetration through the wall of the parchmentless variety.

Un indicador visual de la madurez fisiológica de habichuelas de inflorescencia indeterminada

Dos líneas indeterminadas de habichuela, L-227 y RAB 205, se sembraron en dos estaciones del año para identificar un indicador visual de la etapa de madurez fisiológica que pudiera usarse en el campo. Muestras de 10 plantas se tomaron cada 2 días para determinar la acumulación de materia seca en el grano y el número de vainas verdes, amarillas y secas. Se usaron ecuaciones de regresión lineales, cuadráticas y cúbicas para determinar el número de vainas verdes, amarillas y secas que coincidian con el punto de máxima acumulación de peso seco en el grano. Los coeficientes de determinación para el número de vainas amarillas fueron relativamente bajos; variaron de 0.52 a 0.77. Por otro lado, la mayoría de los coeficientes de determinación para las ecuaciones del número de vainas verdes y de secas fueron cercanos a 0.9, lo que indica que tanto el número de vainas verdes como el de vainas secas podían ser buenos indicadores de madurez fisiológica. La madurez fisiológica de L-227 ocurrió cuando a las plantas les quedaban de 1 a 2 vainas verdes y tenían de 12 a 14 vainas secas. La madurez fisiológica de RAB 205 ocurrió cuando las plantas tenían 2 vainas verdes y 8 vainas secas. Estos resultados indican que el número de vainas verdes, en condiciones de campo, podría ser un mejor indicador de la madurez fisiológica que el número de vainas secas, no solamente porque habrá menos vainas verdes que contar, sino porque las verdes estarían en la parte superior de la planta.

The effect of the gp gene on fruit development in Pisum sativum L.

SUMMARYThe effect of the yellow‐podded (gp) gene on pea fruits was studied with reference to changes in their plastids. The main effect of the gene was on the mesocarp. The chlorophyll concentration of this layer was depressed to less than 5% of that in normal green pods, allowing considerably higher light transmission through the pod wall. Ultrastructural studies showed that the mesocarp of yellow pods contained plastids with an internal membrane system restricted to single and paired membranes and vesicles. Unlike the chloroplasts of green mesocarps they lacked grana. Large starch grains were found in the plastids of mesocarps from both yellow and green pods.Well‐developed chloroplasts, lacking starch grains, were found in the thin parenchymatous lining of the endocarp in yellow and green pods. Here chlorophyll concentrations were comparable in the two pod types and considerably higher than those found in the normal green mesocarp. However, the higher light levels transmitted to this layer in yellow pods correlated with a higher chlorophyll a:b ratio compared with that in the green pod.

The effect of the gp gene on fruit development in Pisum sativum L.

SUMMARYPhotosynthetic activity in the yellow pods of gp.gp lines has been compared with that in normal Gp.Gp pods. As expected from a previous structural study, the occurrence of aberrant plastids in the mesocarp resulted in reduced activity in the gp.gp lines.Illuminated green fruits, 5–16 d post‐anthesis showed net uptake of CO2, from the atmosphere. Positive carbon gain was extended until d 28 in deseeded pods. Conversely, in yellow (gp.gp) fruits no net uptake of CO2, from the atmosphere was observed at any stage, even in deseeded pods, but carbon losses in the light were restricted compared with those in the dark, indicating some photosynthetic activity.Analysis of the photosynthetic machinery within the yellow pods showed considerable differences in the effect of the gp gene on the mesocarp and endocarp layers. Compared with those of green pods, concentrations of RuBP carboxylase in the mesocarp were depressed, and the Hill reaction activity of isolated chloroplasts was virtually undetectable. However, in the parenchyma layer of the endocarp, RuBP carboxylase reached higher concentrations than in Gp.Gp pods, and Hill reaction rates were comparable. There was little difference between the lines in their PEP carboxylase concentrations in either tissue.

Changes in Viability, Germination, and Respiration of Freshly Harvested Soybean Seed During Development

As soybean [Glycine max (L.) Merr.] seeds develop and mature, they gradually desiccate to cause a switch in metabolic processes from a developmental to a germination phase. This investigation was conducted to determine when fresh (nondesiccated), immature soybean seeds acquire the ability to germinate and develop into normal seedlings. Soybean pods were detached from ‘DeSoto’ plants at four developmental stages ranging from full seed (first time the seed filled the locule) to yellow pod [physiological maturity (PM)] in 1981 to 1983. Freshly harvested seeds were immediately evaluated for seed moisture, dry seed weight, viability (radicle protrusion through the testa), germination (normal seedling development), and respiration. Seed and axis dry weight accumulation and moisture loss were nearly identical throughout development. Near maximum viability (93%) of freshly harvested seeds occurred when the seed first filled the locule (35% of final dry seed weight); however, maximum germination (development of normal seedlings) did not occur until maximum accumulation of dry seed weight (PM). Respiration during germination of fresh seed harvested before PM declined prior to radicle emergence without a concomitant decrease in seed moisture, followed by an increase in respiration typical of a germinating seed. Contrary to previous reports, freshly harvested immature soybean seeds did not need a desiccation period prior to expression of maximum viability and normal seedling development.