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Solitary bees of the family Megachilidae are the key pollinators of pigeon pea. Artificial trap nests were used to study nesting parameters, such as occupancy rate, nest establishment time, and building pattern during the vegetative and flowering stages of the Cajanus cajan (Fabaceae). The installed traps were occupied by three different leafcutter bees (Megachile lanata, M. laticeps, M. disjuncta) and one parasitic bee Coelioxys sp. Bees occupied the nest tubes for 16.01 ± 2.82 and 10.23 ± 2.30 days in the vegetative and flowering stages. We recorded 38.33 and 72.50% trap occupancy rates during crop vegetative and flowering stages, respectively. The percent parasitization by Melittobia sp was significantly higher during the vegetative stage (53.67%). Brood cells were parasitized by Coelioxys sp (6.67%) during the flowering stage. Many female bees tend to occupy trap nests with active nest construction during the flowering stage (7.21 ± 2.28 bees). In contrast, male bees merely took shelter inside the traps during the vegetative stage. Thus, it is concluded that female bees possess more wing wear during the vegetative stage of the crop when compared to the flowering stage. We also observed a significant increase in the percent pod set, the number of seeds per pod, and 100 seed weight in the experimental plot compared to the control plot, proving the importance of leafcutter bees for the pollination of Cajanus cajan crop. The present study results confirmed the role of artificial trap nests in providing habitats for the solitary leafcutter bees, thereby increasing their activity and nest abundance, which favors the pollination and better yield in pigeon pea.

Understanding phenology and its regulation is central for the agronomic adaptation of chickpea. We grew 24 chickpea genotypes in 12 environments to analyse: the environmental and genotypic drivers of phenology; associations between phenology and yield; and phenotypes associated with allelic variants of three flowering related candidate loci: CaELF3a; a cluster of three FT genes on chromosome 3; and an orthologue of the floral promoter GIGANTEA on chromosome 4. A simple model with 3 genotype-specific parameters explained the differences in flowering response to daylength. Environmental factors causing flower abortion, such as low temperature and radiation and high humidity, led to a longer flowering-to-podding interval. Late podding associated with poor partition to grain, limiting yield in favourable environments. Sonali, carrying the early allele of Caelf3a (elf3a), was generally the earliest to set pod, had low biomass but the highest harvest index. Genotypes combining the early variants of GIGANTEA and FT orthologues featured early reproduction and high harvest index, returning high yield in favourable environments. Our results emphasise the importance of pod set, rather than flowering, as a target for breeding, agronomic, and modelling applications., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Experimental Biology.)

The success of any hybridization outcome in cowpea is dependent on temperature and humidity, which affect flower initiation, pollen fertility and pod setting. The purpose of this study was to determine the optimal environmental parameters (temperature and humidity) favorable for a successful hybridization outcome in selected cowpea accessions. A total of 512 reciprocal crosses were made between TVu 11953 and Ife Brown cowpea accessions, in the mornings (299 crosses) and evenings (213 crosses). In 2014, 115 crosses were made in the morning, and 71 in the evening. In 2015, 184 crosses were made in the morning and 142 in the evening. Relative to pod set, the morning crosses were significantly more successful (18.73% success; n = 56) than evening crosses (4.69% success; n = 10), regardless of the mother plant (χ2 = 32.06, p < 0.01). Although pod set differed between mother plants significantly (χ2 = 17.28, p < 0.01), 71.03% viable hybrid seeds were obtained following hybridization. Hybridization outcomes were also significantly influenced by the interactions between genotype, temperature and humidity in the study. Temperature ranging from 26.8°C to 27.9°C and humidity from 82% to 86.4% were favorable for pod set. Utmost attention, therefore, should be given to temperature and humidity for achieving success in making intraspecific crosses in cowpea. [ABSTRACT FROM AUTHOR]

A study was conducted in a yard long bean (Vigna unguiculata sup/ssp. sesquipedalis) hybrid VS 50 (Kakkamoola Local) x VS 26 (Vellayani Jyothika) to assess the percentage fruit set at two time intervals and to identify the best time interval for pollination in yard long bean hybrids. Hand pollination was done using VS 50 as female parent and VS 26 as male parent for seven consecutive days at two time intervals, 6.30 – 7.30 am and 7.30 – 8.30 am. Higher percentage of fruit set (36.8 %) was observed between 6:30 – 7:30 a.m. as compared to the time interval 7:30 – 8:30 am. (23.8%). Pollen viability was determined for the parents VS 50 (Kakkamoola Local) and VS 26 (Vellayani Jyothika) at 6.30, 7.30 and 8.30 am. Highest pollen viability for both the parents VS 50 and VS 26 was observed during 7.30 am. The present study shows that the best time interval for crossing in yard long bean is 6.30- 7.30 a.m.

The clover stem borer (CSB; Languria mozardi) is a native North American beetle whose larvae develop inside the stems of a broad range of herbaceous host plants, including sundial lupines (Lupinus perennis). Sundial lupine is an imperiled species in many of the jurisdictions where it occurs, and three rare butterfly species depend on it as a larval host plant. As such, sundial lupines are the focus of many conservation projects. Larval damage to the inside of lupine stems reduces pod production, and is thus a threat to the long-term health of lupine populations. Infestations tend to go unnoticed, partly because so much of the insect's life cycle is spent inside the plant stem. Our description of field indicators is intended to help professionals working on lupine conservation projects recognize CSB activity. In Maryland, sites infested with CSB are connected to the anthropogenic meadow network, whereas sites that are not infested are separated from it by a forest buffer. [ABSTRACT FROM AUTHOR]

Eight intraspecific (four each of mungbean x mungbean and urdbean x urdbean) and 24 interspecific (eight each of mungbean x urdbean, mungbean x ricebean and urdbean x ricebean) crosses were made at five different dates of ten days intervals i.e., September 11-20, 21-30, October 1-10, 11-20 and 21-30 during kharif/late kharif seasons, 2015 to obtain a total of 32 crosses. The per cent crossability at five different dates indicated that it was the highest during October 1-10 in both intra - (mungbean x mungbean, 72.27%, urdbean x urdbean, 55.55%) and interspecific (mungbean x urdbean, 43.24%, mungbean x ricebean, 16% and urdbean x ricebean, 9.92%) crosses. Similarly, the percent ovule fertility recorded was also the highest during October 1-10 in both intra - (mungbean x mungbean, 90.00%, urdbean x urdbean, 83.33%) and interspecific (mungbean x urdbean, 75.00%, mungbean x ricebean, 71.42% and urdbean x ricebean, 60.00%) crosses. Optimum temperature (~22˚C) , followed by low humidity (49.0) and comparatively enhanced sunshine (>8.5 hours) might be responsible for accelerating the highest pod sett during October 1-10 and thus may be suggested as appropriate period for obtaining highest pod setting in Vigna species studied.

Frost is one factor that causes extensive yield losses globally. A study was conducted to evaluate frost damage under field conditions and assess the genetic variation of flowers converting into pods. Diverse faba bean genotypes were evaluated under four growing seasons in a randomized complete block design: three at the University of Sydney, Narrabri, Australia (2014–2016) with three sowing dates, and one at the Agricultural Research Station, Dirab, Riyadh, Saudi Arabia (2016/2017) in one sowing. Visual methods were used to estimate frost damage and record the development of pods. Radiation frost in 2014 (Narrabri) damaged lower pods, while advection frost in 2016/2017 (Dirab) damaged upper pods. The radiation frost formed immediately above the ground; therefore, flowers and pods of taller plants minimized the damage because of their long distance from the ground. The earliest (mid-April) and middle sowing (7 May) suffered more by frost, while a delay in sowing (last week in May) led to frost escape or minor damage. The genotypes IX474/4-3 and 11NF010a-2 showed low sensitivity to frost at the vegetative and reproductive stages. Flowers developed at the beginning of flowering had a faster and higher pod formation rate (41–43%) than those formed later and contributed more to yields. Therefore, a severe frost at the beginning of flowering can cause a significant yield loss as these flowers are the most productive. The frost-tolerant genotypes, and faster and higher pod forming rates, identified in this study can be exploited to breed better varieties in the future.

The experiment was conducted at the research field of Agronomy Division, Bangladesh Agricultural Research Institute (BARI), Joydebpur, Gazipur during Rabi (winter) season of 2010-11 to 2011-12 to determine the optimum rate of nitrogen and phosphorus fertilizer on yield and seed quality of French bean. A randomized complete block design was followed with ten treatment combinations such as N0P0, N0 P44, N50 P44, N100 P44, N150 P44, N200 P44, N150P0, N150P22, N150P33 and N150P55. Number of pods and yield of French bean were significantly increased with the increase in N (150) and P (44) kg ha--1. Averaged over the years, maximum number of pod (9.45 plant-1) and seed yield (1563.33 kg ha-1) were obtained when N and P were applied at the rate of 150 and 44 kg ha-1, respectively while lowest yield to N0P0 treatment in both the years. The treatment (N150P44 kg ha-1) gave the highest seed yield which was 51.4 and 54.30% higher than the control. Quality in terms of germination percentage and vigour index of harvested seed was also significantly influenced by higher doses of N and P while the lowest seed quality from plants that received no fertilizer in both the years.

Eight intraspecific (four each of mungbean x mungbean and urdbean x urdbean) and 24 interspecific (eight each of mungbean x urdbean, mungbean x ricebean and urdbean x ricebean) crosses were made at five different dates of ten days intervals i.e., September 11-20, 21-30, October 1-10, 11-20 and 21-30 during kharif/late kharif seasons, 2015 to obtain a total of 32 crosses. The per cent crossability at five different dates indicated that it was the highest during October 1-10 in both intra - (mungbean x mungbean, 72.27%, urdbean x urdbean, 55.55%) and interspecific (mungbean x urdbean, 43.24%, mungbean x ricebean, 16% and urdbean x ricebean, 9.92%) crosses. Similarly, the percent ovule fertility recorded was also the highest during October 1-10 in both intra - (mungbean x mungbean, 90.00%, urdbean x urdbean, 83.33%) and interspecific (mungbean x urdbean, 75.00%, mungbean x ricebean, 71.42% and urdbean x ricebean, 60.00%) crosses. Optimum temperature (∼22 °C) , followed by low humidity (49.0) and comparatively enhanced sunshine (>8.5 hours) might be responsible for accelerating the highest pod sett during October 1-10 and thus may be suggested as appropriate period for obtaining highest pod setting in Vigna species studied. [ABSTRACT FROM AUTHOR]

Pigeon pea (Cajanus cajan L. Millsp.) is an important grain legume crop of the semi arid tropics and is a major dietary protein source. The extra short duration cultivar of pigeon pea ICPL 88039 was evaluated at ambient(370 μmol/mol) and twice the ambient (700 μmol/mol) concentrations of CO2 in open top chambers (OTCs). The results showed that the crop recorded a significant positive enhanced response for total biomass, fodder yield, grain yield, number of pods and seeds per plant, test weight and HI at elevated CO2. The ANOVA revealed significant differences in response of the characteristics to CO2 concentrations. Under elevated CO2 the total biomass recorded an improvement of 91.3%, grain yield 150.1%, fodder yield 67.1%. The major contributing components for improved grain yield under elevated CO2 were number of pods, number of seeds and test weight which recorded an increase of 97.9%, 119.5% and 7.2%, respectively. The crop maintained a significant positive increase of harvest index (HI) at elevated CO2 with an increment of 30.7% over ambient values. This increase in HI was due to its improved pod set and seed yield under enhanced CO2 concentration thereby emphasizes this crop for sustained food with nutritional security under climate change scenario.

Soybean plants differentiate abundant floral buds, but most of them fail to grow pods and abort during development. Many studies indicated promotive effects of exogenously applied cytokinin on pod setting, but the effects of auxin application on pod set are ambiguous. In this study, we examined the changes in the concentrations of endogenous auxin and cytokinin in racemes and the effects of application of the two hormones on pod setting to clarify the role of auxin and cytokinin in soybean pod setting. The long-raceme soybean genotype IX93-100 was grown in pots and in the field. The auxin (IAA, indoleacetic acid) concentration in racemes was high for a long period from pre-anthesis to 9 days after anthesis (DAA) of the first flower on a raceme, but the cytokinin concentration was high for a short period, with a peak at 9 DAA. The IAA concentration was higher in distal portions of racemes, but the cytokinin concentration was higher in basal portions of racemes. In pot-grown plants, IAA applied to racemes tended to reduce the number of flowers and pods. In contrast, 6-benzylaminopurine (BA) applied to racemes before anthesis tended to reduce the number of flowers and pods, and that applied around 7 DAA significantly increased the pod-set percentage. However, these effects of IAA and BA application were slight in field-grown plants. These results indicate that the concentration of endogenous auxin and cytokinin in racemes changes in a different manner, and that cytokinins have a positive, and auxin a negative effect on pod setting when respective hormones are applied to racemes after the anthesis stage.

A large proportion of soybean flowers abort during development. Pod set is significantly affected by the availability of assimilate and cytokinin in the flowers, but their synergistic effects on pod set remain unclear. The objective of this study was to examine whether pod set at specific nodes of a plant is enhanced by increasing the source-sink ratio and applying cytokinin to the nodes. The source-sink ratio was manipulated by removing floral buds excluding the specific nodes. As the ratio increased, the number of pods per node of control plants increased curvilinearly, reaching a plateau at high source/sink ratios. By contrast, in the cytokinin-applied plants, the number of pods per node increased without the plateau with increasing source/sink ratio, either by increasing the number of flowers or by increasing the pod-set percentage depending on the year. The results indicated that cytokinin plays a promotive role in increasing pod number in the plants with high levels of assimilate availability.

The objective of this study is to elucidate the effects of CO2 enrichment during different growth periods on flowering, pod set and seed yield in soybean (Glycine max (L.) Merr.). Soybean cultivar‘Fukuyutaka’was grown in a growth chamber of the Institute of Bioresources Research Center of Kyushu Electric Power Co., Inc. at Saga, Japan (33°17’-N, 130°18’-E) under natural light. The CO2 concentrations were maintained at 350 µmol mol−1 for ambient CO2 and at 700 µmol mol−1 for CO2 enrichment. CO2 concentration was elevated during the whole growth period (WP), vegetative growth period (VP) or reproductive period (RP). Seed yield was increased by CO2 enrichment during RP or WP due to the increase of pod number, but not by CO2 enrichment during VP.Although CO2 enrichment had no effect on the number of flowers, CO2 enrichment during RP increased the pod number on all raceme orders and that during WP increased the pod number in the secondary and tertiary racemes. It is suggested that an increase of seed yield by CO2 enrichment is mostly brought by the improvement of pod set, mainly on the high-order racemes that opened later during flowering period, and that the response of seed yield to CO2 enrichment is mainly attributed to the response during RP.

Soybean (Glycine max (L.) Merr. cv. Enrei) plants were grown in pots (15-L volume) placed in a greenhouse with ventilation. At the time when the first flower opened, pots were transferred to growth chambers with natural lighting under day temperature of 30°C and night temperatures of 20, 25 or 30°C. The numbers of flowers opened and pods set each day were recorded and the seed yield and yield components were investigated after harvest. The increase in night temperature decreased the seed size and increased the number of flowers and pods. As a result, the seed weight per plant was unaffected by night temperature. However, high night temperatures increased the number of flowers on the secondary and tertiary racemes. These flowers opened after the 18th day of the flowering period and showed a high rate of pod setting. These results suggest that a high night temperature stimulated flower opening and pod setting in the secondary and tertiary racemes. The increases in the numbers of flowers and pods could serve to moderate the reduction of seed yield caused by a high night temperature.

In soybean, long days during post-flowering increase seed number. This positive photoperiodic effect on seed number has been previously associated with increments in the amount of radiation accumulated during the crop cycle because long days extend the duration of the crop cycle. However, evidence of intra-nodal processes independent of the availability of assimilates suggests that photoperiodic effects at the node level might also contribute to pod set. This work aims to identify the main mechanisms responsible for the increase in pod number per node in response to long days; including the dynamics of flowering, pod development, growth and set at the node level. Long days increased pods per node on the main stems, by increasing pods on lateral racemes (usually dominated positions) at some main stem nodes. Long days lengthened the flowering period and thereby increased the number of opened flowers on lateral racemes. The flowering period was prolonged under long days because effective seed filling was delayed on primary racemes (dominant positions). Long days also delayed the development of flowers into pods with filling seeds, delaying the initiation of pod elongation without modifying pod elongation rate. The embryo development matched the external pod length irrespective of the pod's chronological age. These results suggest that long days during post-flowering enhance pod number per node through a relief of the competition between pods of different hierarchy within the node. The photoperiodic effect on the development of dominant pods, delaying their elongation and therefore postponing their active growth, extends flowering and allows pod set at positions that are usually dominated. [ABSTRACT FROM AUTHOR]

A large proportion of flowers abscise during development in soybean (Glycine max L. Merr.). A reduction in this abscission might increase pod and seed number, and thereby can lead to an increased yield. Previous studies showed that pod-set probability was greater at proximal positions of individual racemes, and that the probability was enhanced by the exogenously applied cytokinins. However, whether intra-raceme variation in the pod-set probability relates to endogenous cytokinin levels remains unknown. To address this question, intra-raceme variation in cytokinin content and pod-set probability was investigated. A soybean genotype 1X93-100, which has long racemes, was grown in an environmentally controlled chamber (30/20°C day/night temperature, 15 h day length, 600 μmol m–2s–1 photosynthetic photon flux density). Flowers, which were divided into three floral positions (proximal, middle, distal) on individual racemes, were sampled at intervals after anthesis. The cytokinins in the samples were identified by gas chromatography-mass spectrometry (GC-MS) and further quantified by enzyme immunoassay (EIA). The GG-MS analysis revealed that cis-zeatin riboside (c-ZR) and isopentenyl-adenosine (iPA) were predominant forms of cytokinin in soybean racemes. The total amount of these cytokinins in racemes, which was monitored by EIA, peaked one to two weeks after the first flowering on a raceme, when pod development was initiated. Within individual racemes, the total cytokinin concentrations were greater at more proximal floral positions, as was the probability of pod set. Removal of proximal flowers at anthesis enhanced both cytokinin concentrations and pod set at middle positions on the raceme. Thus, pod-set probability was significantly associated with the cytokinin concentration at different floral positions within individual soybean racemes.

Perennial vetch ( Vicia unijuga) is a wild plant found in parts of East Asia and potentially valuable as a forage species for more extreme environments. Information on its reproductive system and pollination biology is needed for progress in domestication of the species. We characterized the reproductive system of perennial vetch as facultative xenogamy (i.e. it is largely cross-pollinated by insects but is also self-compatible and can self-pollinate). There was no significant difference (P > 0.05) in the fruit set ratio between insect cross-pollination and artificial cross-pollination at the seed maturation stage, but natural self-pollination was inefficient. In our study conducted on the Tibetan plateau, eight insect species (especially certain bumble bees) are identified as potential pollinators, and four other insect species belonging to the Lepidoptera and Diptera visited flowers but are unlikely to be pollinators. The flower visitation rate of wild bumble bees was 1.6-3.3 times higher than domestic honeybees, with Bombus lepidus having the highest visitation rate of 15.7 florets/min. The diurnal floret opening rhythm of perennial vetch was synchronized with diurnal activity of potential pollinators. Optimal pollination of perennial vetch would likely be achieved using wild bees, as they have behaviour characteristics and flower tripping ability necessary, and are present in sufficient numbers to be efficient pollinators of this crop. However, even with sufficiency of pollination, there remains a fundamental problem with low fruit set which requires further investigation from a plant biology perspective. [ABSTRACT FROM AUTHOR]

High temperature ( HT) stress is one of the major environmental factors influencing yield of soybean ( Glycine max L. Merr.) in the semi-arid regions. Experiments were conducted in controlled environments to study the effects of HT stress on anatomical changes of pollen and their relationship to pollen function in soybean genotype K 03-2897. Objectives of this study were to (a) quantify the effect of HT stress during flowering on pollen function and pod set and (b) observe the anatomical changes in pollen grains of soybean plants grown under HT stress. Plants were exposed to HT (38/28 °C) or optimum temperature ( OT, 28/18 °C) for 14 days at flowering stage. HT stress significantly decreased in vitro pollen germination by 22.7 % compared to OT. Pollen from HT stress was deformed; it had a thicker exine wall and a disintegrated tapetum layer. HT stress decreased pod set percentage (35.2 %) compared to OT. This study showed that decreases in pollen in vitro germination by HT stress were caused by anatomical changes in pollen, leading to decreased pod set percentage under HT stress. [ABSTRACT FROM AUTHOR]

Abstract: High temperature during reproduction is a major factor limiting the yield of chickpea (Cicer arietinum L.). Observations in the field from late season experiments (February–May) and various high temperature regimes generated in controlled environments showed clear genetic variation in male reproductive tissue (anther and pollen), its function (pollen germination and tube growth) and pod set. Greater pod setting ability of heat tolerant genotypes (ICC 1205 and ICC 15614) compared to heat sensitive genotypes (ICC 4567 and ICC 10685) was observed in both the field and controlled conditions. Both anthers and pollen showed more structural abnormalities under stress such as changes in anther locule number, anther epidermis wall thickening and pollen sterility, rather than function (e.g. in vivo pollen tube growth). The critical temperature for pod set was ≥37°C in heat tolerant genotypes (ICC 1205 and ICC 15614) and ≥33°C for heat sensitive genotypes (ICC 4567 and ICC 10685). Overall, pod set showed greater sensitivity in the controlled environments where a 67% reduction was observed at ≥34/19°C compared to the control (27/16°C). In the field, a pod set reduction of more than 50% occurred at high ambient day temperature (36°C) and the stigma was still receptive at 40.2/25.5°C. In contrast, under controlled conditions the stigma was still receptive at 35/20°C in four genotypes. Clearly, chickpea pollen grains are more sensitive to high temperature than the stigma in both the field and controlled environments. Among the four genotypes tested, ICC 1205 was the most heat tolerant and ICC 4567 was the most heat sensitive. [Copyright &y& Elsevier]

Abstract: Fertilized peanut (Arachis hypogaea L.) ovaries develop into aerial gynophores known as pegs, which are supposed to endure delayed penetration into the soil (pegging) caused by increased surface soil strength promoted by drought. There is no information, however, on the pattern of decay in peg viability in response to impaired pegging duration, which may affect seed yield severely. Two peanut cultivars (Florman and ASEM) were grown in pots under two contrasting water availability levels (WA) imposed at the R2 growth stage (start of peg formation). Pegs of ca. 5mm were tagged at this stage, and WA extended for 10 different periods (between 7 and 41 days) of restriction to pegging (RP n ). Tagged pegs were used for analysis of histological changes and pod set evaluation. Reduced WA caused a significant (P ≤0.001) decrease in peg viability and pod set, but no negative effect was detected on these traits for at least 11 days of treatment. The extent of maximum peg viability (stage 1) was shorter for water deficit (11 days of RP) than for well-watered plants (15 days of RP), and was followed by a phase of linear decrease (maximum rate between −0.056 and −0.073 days−1) in peg viability (stage 2). The latter finished at ca. 33 days of RP, with permanent loss in peg viability (stage 3). Tissue deterioration began at the start of stage 2, until complete atrophy was reached at the start of stage 3. This trend proceeded faster for water-deficit pots and cultivar Florman. [Copyright &y& Elsevier]

Abstract: Pod set, a critical process for legume crop productivity, is sensitive to environmental stress such as low or high temperature or drought. At higher latitudes, pod set at low temperatures is one of the most important processes for efficient soybean production. The present study was carried out to determine which flower developmental stage was most sensitive to low temperature and how low temperature interrupts the pod setting process. Soybean flowers at various developmental stages were subjected to low temperatures, and the percentage elongation of pods was subsequently measured. Two low temperature-sensitive stages were found. The first was an early developmental stage approximately 12.5 days before the anthesis of individual flowers. The second stage occurred 3–4 days before anthesis. An investigation of the pollen grain number on stigma suggests that insufficient pollination causes low pod set under low temperature stress at both temperature-sensitive stages. Tetrad-shaped abnormal pollen grains were observed when flowers were subjected to low temperature at the first sensitive stage; thus, this stage might be the tetrad stage or the stage prior to tetrad formation. Furthermore, at the first sensitive stage, pollen development deficiency was one of the causes of poor pod set under low temperature conditions. [Copyright &y& Elsevier]

Terminal drought during the reproductive stage is a major constraint to yield of chickpea in many regions of the world. Termination of watering (WS) during podding in a small-seeded desi chickpea (Cicer arietinum L.) cultivar, Rupali, and a large-seeded kabuli chickpea cultivar, Almaz, induced a decrease in predawn leaf water potential (LWP), in the rate of photosynthesis, and in stomatal conductance. Compared to well-watered (WW) controls, the WS treatment reduced flower production by about two-thirds. In the WW treatment, about 15% of the flowers aborted and 42% (Rupali) and 67% (Almaz) of the pods aborted, whereas in the WS treatment 37% and 56% of the flowers aborted and 54% and 73% of the pods aborted, resulting in seed yields of 33% and 15% of the yields in WW plants in Rupali and Almaz, respectively. In vitro pollen viability and germination in Rupali decreased by 50% and 89% in the WS treatment, and pollen germination decreased by 80% in vivo when pollen from a WS plant was placed on a stigma of a WW plant. While about 37% of the germinated pollen tubes from WW plants and 22% from the WS plants reached the ovary in the WW plants, less than 3% of pollen grains reached the ovary when pollen from either WS or WW plants was placed on a stigma of a WS plant. It is concluded that, in addition to pod abortion, flower abortion is an important factor limiting yield in chickpea exposed to terminal drought and that water deficit impaired the function of the pistil/style more than the pollen. [ABSTRACT FROM PUBLISHER]

The aim of this study was to determine if and how the honeybee reduces the blooming period of canola ( Brassica napus). Colonies were installed in different fields of canola in the Chaudiere-Appalaches (two replicates) and Quebec City (one replicate) regions to create a density gradient of zero to three colonies per hectare. To calculate the blooming period under these conditions, 10 labelled plants were caged in the field, out of the reach of pollinators, and 10 others were labelled in the field and exposed to foragers. The number of flowers found on each plant was recorded daily. This study also aims at demonstrating that the canola plant will produce new flowers as long as it does not reach its maximum carrying capacity, thereby extending the blooming period. To simulate the fall of unfertilized flowers, a predetermined number of flowers from 20 randomly selected plants in one of the replicates were cut off every day. The plant, when it reaches its maximum carrying capacity, stops producing new flowers. With three colonies per hectare, the blooming period was reduced by 3.8 days, or 17 % compared with in the absence of pollinators. Because of the efficient pollen transfer to the stigma, the honeybees do not only cause the flower to live for a shorter period of time, but they also bring about a decrease in the number of flowers produced by the plant, thereby reducing the duration of blooming period. [ABSTRACT FROM AUTHOR]

Chickpea ( Cicer arietinum L.) is more sensitive to water stress during its reproductive growth and consequently experiences substantial yield loss. Wild species being relatively tolerant to abiotic stresses offer a potential gene source for incorporation of drought tolerance in cultivated species. In the present study, the differential stress sensitivity of wild ( Cicer reticulatum Ladiz.) and cultivated species ( C. arietinum) was evaluated by subjecting the plants of both the species to water stress for 14 days during the reproductive phase and examined for stress injury, endogenous status of polyamines (PA) and abscisic acid (ABA). Comparatively, the cultivated species experienced higher stress injury (assessed as electrolyte leakage, 2,3,5-triphenyl tetrazolium chloride reduction ability, chlorophyll loss) as well as decreased leaf water potential (Ψw; −2.48 MPa) than the wild species (−1.98 MPa). The stressed plants of cultivated species lost more number of flowers (62 %) and pods (65 %) when compared with the unstressed ones while those of wild species showed 30 % and 44 % loss, respectively. The number of infertile pods was significantly more in stressed plants of cultivated species than in those of wild species. The endogenous status of PA revealed that putrescine (PUT), spermidine (SPD) and spermine (SPM) levels accumulated to a higher extent in the cultivated species relative to the wild species until the eighth day of stress, and thereafter, the wild species had significantly higher levels of PA. In contrast, ABA levels increased to a higher extent in the wild species until the eighth day of stress and declined subsequently to a greater degree than the cultivated species. The injury to reproductive growth appeared to accentuate with reduction in leaf Ψw that was coupled with depletion of PA in both the species, especially in the cultivated one. Exogenous application of 10 m m PUT partially alleviated the damage to reproductive growth by increasing the leaf water status and chlorophyll content while decreasing the ABA content, which resulted in improvement of retention of flowers and pods, particularly in the cultivated species. [ABSTRACT FROM AUTHOR]

Pollination is an essential step in the seed production of canola, Brassica napus L. It is achieved with the assistance of various pollen vectors, but particularly by the honey bee, Apis mellifera L. Although the importance of pollination has been shown for the production of seed crops, the need to introduce bee hives in canola fields during flowering to increase oil seed yield has not yet been proven. With the purpose of showing this, hives of A. mellifera were grouped and placed in various canola fields in the Chaudière-Appalaches and Capitale-Nationale regions (nine fields; three blocks with three treatments; 0, 1.5, and 3 hives per hectare). A cage was used to exclude pollinators and bee visitations were observed in each field. After the harvest, yield analyses were done in relation to the bee density gradient created, by using pod set, number of seeds per plant, and weight of 1000 seeds. Results showed an improvement in seed yield of 46% in the presence of three honey bee hives per hectare, compared with the absence of hives. The introduction of honey bees contributed to production and consequently, these pollinators represented a beneficial and important pollen vector for the optimal yield of canola. [ABSTRACT FROM AUTHOR]

• Background and Aims The physiological reasons for reduced pod set in soybean (Glycine max) caused by drought during anthesis are not established. The objective of this study was to investigate the involvement of photosynthetic rate (A), pod endogenous abscisic acid (ABA) and exogenously applied ABA and 6-benzylaminopurine (BA) in regulating pod set in soybean during drought.• Methods Two pot experiments were done in a controlled-environment glasshouse. In expt I, soybeans were either well-watered (WW) or droughted by withholding water from 4 d before to 4 d after anthesis (DAA). In expt II, soybeans were drought-stressed (DS) from ?4 to 4 DAA. From ?2 to 4 DAA, some of the WW and DS plants were treated with 0·1 mm ABA or 1 mm BA.• Key Results Drought stress decreased A, but increased pod ABA concentration ([ABA]). Pod set decreased only when A had decreased by 40 %, and pod [ABA] had increased 1·5-fold. Beyond the thresholds, pod set correlated positively with A and negatively with pod [ABA]. Exogenously applied ABA decreased A and pod set in WW plants, whilst it increased A and pod set in DS plants; exogenous BA had opposite effects. In these plants, pod set correlated linearly with A.• Conclusions Drought-induced decrease in A is significant in inducing pod abortion, probably as a consequence of carbohydrate deprivation. The effects of ABA and BA on pod set may be partially due to their effects on photosynthate supply. [ABSTRACT FROM AUTHOR]

Root-originated chemical signals have been shown to regulate the response of vegetative shoot to drought in soybeans (Glycine max L. Merr.). However, their roles in the growth of soybean reproductive structures under drought stress have not yet been investigated. To explore this, a glasshouse experiment was conducted in which potted soybeans were either well-watered (WW) or subjected to six levels of drought stress. Irrigation was withheld in pots at six different dates before anthesis to induce drought of different severity (D1–D6) at sampling, viz. 4 days after anthesis (DAA). Root water potential, leaf water potential, pod water potential, xylem sap [ABA], pod fresh weight (FW), and pod set percentage were determined. Soil water status in the pot was expressed as the fraction of transpirable soil water (FTSW). Pod FW started to decrease at FTSW=0.43±0.02, when pod water potential was similar to that in the WW plants, while root water potential had decreased to −0.15 MPa and xylem sap [ABA] had increased 9-fold as compared with the WW plants. Pod set started to decrease at FTSW=0.30±0.01, and coincided with the decrease in pod water potential. Pod set started to decrease only when pod FW had decreased ca. 30%. Based on the results, a potential role of drought-induced increase in xylem sap ABA in affecting pod growth was suggested. We proposed that a low pod water potential, which might have led to disruptions in metabolic activities in the pods, is important in determining pod abortion. [Copyright &y& Elsevier]

Reproductive efficiency was successfully manipulated by the application of different concentrations of triadimefon at pre-flowering, flowering and post-flowering stages in chickpea (Cicer arietinum L.). Triadimefon improved the parameters determining reproductive efficiency. Yield was significantly improved due to reductions in flower and pod abscission by the application of triadimefon, which also lowered the ethylene levels in leaves, flowers and pods and delayed senescence. These findings suggest a relationship between ethylene level and reproductive efficiency in chickpea. Further, they indicate that triadimefon can be used for chemical manipulation of the reproductive efficiency of chickpea under field conditions. [ABSTRACT FROM AUTHOR]

The vector role of thrips in pollinating several fabaceous flowers has been studied. The flowring phenology showed a coincidence with the life cycle of the thrips species. The population dynamics of the thrips, crop-weed dispersal, the pollen carrying efficiency and the percentage of pod set are discussed. [ABSTRACT FROM AUTHOR]

Frost is one factor that causes extensive yield losses globally. A study was conducted to evaluate frost damage under field conditions and assess the genetic variation of flowers converting into pods. Diverse faba bean genotypes were evaluated under four growing seasons in a randomized complete block design: three at the University of Sydney, Narrabri, Australia (2014–2016) with three sowing dates, and one at the Agricultural Research Station, Dirab, Riyadh, Saudi Arabia (2016/2017) in one sowing. Visual methods were used to estimate frost damage and record the development of pods. Radiation frost in 2014 (Narrabri) damaged lower pods, while advection frost in 2016/2017 (Dirab) damaged upper pods. The radiation frost formed immediately above the ground; therefore, flowers and pods of taller plants minimized the damage because of their long distance from the ground. The earliest (mid-April) and middle sowing (7 May) suffered more by frost, while a delay in sowing (last week in May) led to frost escape or minor damage. The genotypes IX474/4-3 and 11NF010a-2 showed low sensitivity to frost at the vegetative and reproductive stages. Flowers developed at the beginning of flowering had a faster and higher pod formation rate (41–43%) than those formed later and contributed more to yields. Therefore, a severe frost at the beginning of flowering can cause a significant yield loss as these flowers are the most productive. The frost-tolerant genotypes, and faster and higher pod forming rates, identified in this study can be exploited to breed better varieties in the future. [ABSTRACT FROM AUTHOR]