Floral Abortion Research Articles

Estimate of chickpea production (Cicer arietinum L.) as a function of plant phenology

Chickpea is a crop of the indeterminate type which can be an advantage to estimate in advance the production of this crop. The lack of water, cold or heat are the most limiting factors for the success of this culture; in the emergency phase, situations of waterlogging or extreme drought lead to an irregular installation of the culture, on the other hand, drought, excess water and extreme heat during the reproductive period, cause floral abortion and/or shorter cycles, and consequently, smaller income. Chickpea yield essentially depends on the number of seeds per unit area, which in turn depends on the length of the reproductive period. This is a problematic situation that proves the complexity of estimating the yield in leguminous crops in relation to species of determined habit. We try to know the dates of development of chickpeas, namely when the vegetative apex becomes reproductive (Beginning of Flowering, BF) and when the last flower of the apex no longer develops (End of Flowering, EF), this knowledge is fundamental anticipate and estimate the productive potential. Portugal is a country with a typical Mediterranean climate that has high capacity to produce grain legumes and the chickpea breeding program started at Plant Breeding Station, Elvas, Portugal in 1986. Since this data we have determined the dates of the BF and EF and, due to the difference between the two, the Reproductive Period (RP); the longer this period, the greater the number of pods and seeds per plant, and, as a consequence, greater final productions. In this way, over the course of 24 years, we have been recording the dates of entry into flowering and the end of flowering according to the thermal sum in Growing Degree Days (GDD) of by genotype, by trial and by year. In this analysis it was found that the BF is achieved when the sum of the GDD reaches 757 ºC, for maximum temperatures of 23 ºC, and the EF for sums of 1224 ºC and maximum temperatures of 30 ºC, that is, when temperatures above 28 ºC are registered, for two or three days in a row, is an indicator that the EF is approaching. It may happen later if precipitation occurs when the temperature reaches those values, but it varies from genotype to genotype. The new varieties, Elipse, Electra, Eleia, Eladir and Elfo confirm this situation, with the ELEIA variety standing out earlier in flowering.

An Overview of the Role of Smallholders in Oil Palm Production Systems in Changing Climate

Oil palm production contributes tremendously to the economies of tropical countries, a location where cultivation takes place. The cultivation of oil palm is usually dominated by smallholders and produces about 40% of global palm oil demand. Therefore, in this study, we aim to investigate the role of smallholder oil palm growers in ensuring palm oil production in a changing climate. This study was based on a conventional literature review. Relevant articles were retrieved using search terms such as “climate change” or “oil palm” or “climate change and oil palm” OR “oil palm smallholders” OR “oil palm growers”. The documents were selected by (i) examining the title of the document, (ii) the abstract (iii) and the content of the document sequentially. Only documents that meet the inclusion criteria were selected for the review. The results of this study demonstrated that global climatic changes have a greater negative effect on oil palm production in the tropics. Rising temperatures result in water stress to the palms, as does variability in rainfall, which reduces productivity, declining floral abortion, increase in pests and diseases infestation, and yield loss. Oil palm smallholder growers contribute immensely to global food security. Smallholders are estimated to manage approximately 40% of the global oil palm planted area, producing 40% of the global palm oil demand. In Africa, smallholders produced more than 60% of palm oil demand, 33% in Papua New Guinea, and 40% in Malaysia. In Latin America, where 87% of oil palm growers are smallholders, they produce over 60% of the demand for palm oil. Oil palm production creates jobs and poverty alleviation, provides the most efficient oil, provides vitamins for body-building, and provides nutritious and healthy food. This study recommends long-term and short-term policies on climate change and oil palm, improved regional academic leadership, with a focus on collaboration with scientists in consumer countries, improved institutional research, and collaboration in research between producer and major consumer countries.

Foliar Application of Salicylic Acid to Mitigate Water Stress in Tomato.

Salicylic acid (SA) is an important plant regulator reported as a mitigator of water deficit in plants, however without a recommendation for use in field conditions. Thus, this research aims to validate the use of SA under field conditions in regions with low water availability. For that, we evaluated CO2 assimilation (A), stomatal conductance (gs), transpiration (E), water use efficiency (WUE), and carboxylation efficiency (A/Ci) at 15, 30, and 45 days of continuous stress water deficit, as well as the application of salicylic acid (0.0; 0.5; 1.0; 1.5; 2.0 mM) in tomato plants subjected to continuous water deficit (45 days), in two years (2019 and 2020). The water deficit reduced the A, gs, E and A/Ci, while the foliar application of SA increased these parameters in all evaluated times, resulting in similar or even higher values than in plants without water deficit. Water deficit caused floral abortion in tomato plants, without the application of SA, reducing the number of fruit production. In contrast, plants that received about 1.3 mM of SA increased A and A/Ci and translocated the photo-assimilates, mainly to flowers and fruits, reducing floral abortion and increasing fruit production. Thus, foliar application of SA was efficient in mitigating the deleterious effects of water deficit in tomato plants regarding the gas exchange and fruit production.

Half Friend, Half Enemy? Comparative Phytophagy between Two Dicyphini Species (Hemiptera: Miridae).

Simple SummaryOmnivorous predators, such as some mirids, are important biological control agents in several vegetable crops since they are generalists and can survive in the crop in the absence of prey. Nesidiocoris tenuis is a mirid used worldwide and its phytophagy is well known, which is not the case for the Palearctic Dicyphus cerastii. To use the latter in biological control it is crucial to evaluate the damage it causes to plants. We compared these two mirid species, under laboratory and semi-field conditions, regarding the damage they caused to plants and fruit, and their location on the plant versus on the fruit. Both species produced plant damage (scar punctures on leaves and necrotic patches on petioles) and caused flower abortion, at a similar level, however, only N. tenuis produced necrotic rings. Overall, N. tenuis females produced more damage to tomato fruit than D. cerastii. There was an increased frequency of D. cerastii females found on the plants over time, which did not happen with N. tenuis. Our results suggested that although D. cerastii caused less damage to tomato fruit than N. tenuis, it did feed on the fruit and could cause floral abortion, which requires field evaluation and caution in its use.Despite their importance as biological control agents, zoophytophagous dicyphine mirids can produce economically important damage. We evaluated the phytophagy and potential impact on tomato plants of Dicyphus cerastii and Nesidiocoris tenuis. We developed a study in three parts: (i) a semi-field trial to characterize the type of plant damage produced by these species on caged tomato plants; (ii) a laboratory experiment to assess the effect of fruit ripeness, mirid age, and prey availability on feeding injuries on fruit; and (iii) a laboratory assay to compare the position of both species on either fruit or plants, over time. Both species produced plant damage, however, although both species produced scar punctures on leaves and necrotic patches on petioles, only N. tenuis produced necrotic rings. Both species caused flower abortion at a similar level. Overall, N. tenuis females produced more damage to tomato fruit than D. cerastii. There was an increased frequency of D. cerastii females found on the plants over time, which did not happen with N. tenuis. Our results suggested that, although D. cerastii caused less damage to fruit than N. tenuis, it still fed on them and could cause floral abortion, which requires field evaluation and caution in its use in biological control strategies.

Nitrogen nutrition contributes to plant fertility by affecting meiosis initiation

Nitrogen (N), one of the most important plant nutrients, plays crucial roles in multiple plant developmental processes. Spikelets are the primary sink tissues during reproductive growth, and N deficiency can cause floral abortion. However, the roles of N nutrition in meiosis, the crucial step in plant sexual reproduction, are poorly understood. Here, we identified an N-dependent meiotic entrance mutant with loss of function of ELECTRON TRANSFER FLAVOPROTEIN SUBUNIT β (ETFβ) in rice (Oryza sativa). etfβ displayed meiosis initiation defects, excessive accumulation of branched-chain amino acids (BCAAs) and decrease in total N contents in spikelets under N starvation, which were rescued by applying excess exogenous inorganic N. Under N starvation, ETFβ, through its involvement in BCAA catabolism, promotes N reutilization and contributes to meeting N demands of spikelets, highlighting the impact of N nutrition on meiosis initiation. We conclude that N nutrition contributes to plant fertility by affecting meiosis initiation.

Antitranspirants Partially Mitigate Auxin Herbicide Injury on Tomato Plants

The use of dicamba and 2,4-D products on herbicide-tolerant crops has resulted in numerous cases of off-target movement and injury to sensitive plants, including tomato (Solanum lycopersicon L.). Two greenhouse studies were conducted to determine whether ‘Big Beef’ (‘BB’) or ‘Florida 91’ (‘FL’) tomato plants pretreated with an antitranspirant, including Moisture-Loc (ML) at 100 mL·L−1, TransFilm (TF) at 50 g·L−1, or Wilt-Pruf (WP) at 100 mL·L−1, mitigated injury from synthetic auxin herbicides. Dicamba or 2,4-D was applied at a rate corresponding to 1/200 of the manufacturer’s labeled rate of 0.56 kg ae/ha or 1.06 kg ae/ha, respectively. At 2 weeks after treatment (WAT), plants treated with ML or WP before either herbicide exhibited injury symptoms, but they were always less severe than those treated with the herbicide alone for both cultivars. However, shoot length measurements indicated that none of the antitranspirants consistently provided protection against herbicide injury at 2 WAT. By 12 WAT, ML or WP used before either herbicide increased the number of live reproductive organs compared with dicamba or 2,4-D alone for both cultivars. Floral abortion on tomato plants was also reduced when ML or WP was applied before an herbicide treatment by 12 WAT. Although WP and ML did not provide complete protection against synthetic auxin herbicide injury, the concept of using film-forming barriers may be useful in mitigating some of the short-term effects of drift on plants.

Effects of Exogenous Salicylic Acid on Drought Response and Characterization of Dehydrins in Impatiens walleriana.

Impatiens walleriana is a valued ornamental plant sensitive to drought stress. We investigated whether the foliar application of 2mM salicylic acid (SA) can protect potted I. walleriana plants from drought stress. The plants were divided into: watered plants, drought-stressed plants, watered plants treated with SA and drought-stressed plants treated with SA. The number of flowers and flower buds, relative water content (RWC), contents of malondialdehyde (MDA) and proline (Pro) and the activities of superoxide dismutases, catalases and peroxidases were recorded at different time points. Three dehydrin sequences were identified in de novo assembled leaf transcriptome: IwDhn1, IwDhn2.1 and IwDhn2.2. Drought stress caused wilting, floral abortion, reduction of RWC and increased MDA—an indicator of lipid peroxidation. In response to drought, Impatiens accumulated Pro and induced chloroplastic Cu/ZnSOD and two peroxidase isoforms. The most remarkable drought response was strong induction of IwDhn2.1 and IwDhn2.2. Rehydration restored RWC, Pro level, Cu/ZnSOD activity and dehydrins expression in drought-stressed plants approximately to the values of watered plants.SA had ameliorating effects on plants exposed to drought, including prevention of wilting, preservation of RWC, increased Pro accumulation, modulation of antioxidative activities and remarkable decrease of lipid peroxidation, but without effects on flowers’ preservation.

The effect of water deficit on inflorescence period at palm oil productivity on peatland

Various factors influence palm oil production, including planting material, environment (climate and soil), and cultivation management. The environment occupies a crucial position that can affect crop production potential even with optimal cultivation management. Unfavorable climatic conditions, for instance, drought, can cause water deficit, which has implications for crop productivity. This paper aims to get a comparative study for the effect of water deficit on the inflorescence period, namely the sex determination phase (29 months before harvesting) and floral abortion (10 months before harvesting). The research was carried out on oil palm plantations on peatland in Riau, Indonesia, with the characteristic annual rainfall of 2000 mm/ year. This study employs a simple regression analysis on panel data of five years and two estates for data analysis. The result highlights that the increase of a 100 mm water deficit on oil palm peatland plantation impacts the decrease in productivity by 6% in the sex determination phase. In contrast, in the floral abortion phase, the decline in productivity is more significant, namely 7%. The analysis also indicated that the research deficit had more impact on the bunch number than the bunch weight.

Cold priming the chickpea seeds imparts reproductive cold tolerance by reprogramming the turnover of carbohydrates, osmo-protectants and redox components in leaves

Chickpea, a vital food legume, shows high sensitivity to cold stress at reproductive stage, and temperatures below 20/10 °C, (as day/night temperature) at this stage result in disruption in developmental and functional aspects of reproductive components, causing floral abortion, poor pods and significant yield losses. In the present study, chickpea seeds (a cold sensitive genotype GPF2) were cold primed at 5 °C ± 1 °C in the dark for 30 days, followed by gradual air-drying at 15 °C to the original moisture content (11–13%). The crop was raised in the month of November from non-primed and primed seeds in the outdoor environment (temperature profile: 11.7 °C; mean day/night temperature; 1300–1500 μmol m−2 s−1 light intensity, 65–70% relative humidity), until the onset of budding and flowering (45 days after sowing). Subsequently, the plants were separated into different sets to impose following treatments in controlled environment a) control (at optimum temperature; a set of plants were grown at optimum temperature (25/18 °C) until maturity, b) cold-stressed; a set of the plants were grown at low temperature (15/8 °C) until maturity, c) raised from cold-primed seeds but grown at optimum temperature (25/18 °C) until maturity, d) raised from cold-primed seeds and exposed to low temperature (15/8 °C), until maturity. The plants were tested for various traits in the leaves at 0–25 days after exposure to stress. Cold stress resulted in damage to membranes, photosynthetic ability (as loss of chlorophyll, photosystem II function and chlorophyll fluorescence, stomatal conductance), photo-assimilation capacity (as sucrose metabolism), hydration status (as leaf water content), production of osmolytes (as disruption in metabolism of proline, trehalose, glycine betaine, and GABA production) and decreased the redox status of the cells (as decrease in activity and expression of various enzymatic and non-enzymatic antioxidants. Reproductive function was markedly decreased, as was evident from reduction in pollen viability, pollen germination, stigma receptivity and ovule viability). Pod number and seed weight plant−1 showed 65.5 and 68.4% reduction because of cold stress. The plants raised from cold-primed seeds were remarkable benefitted at reproductive stage, which showed significantly improved pollen and stigmatic function, resulting in considerable recovery of the pod number and seed weight plant-1. The benefits of the cold priming were possibly related to improved leaf function (hydration status, photosynthetic and carbon fixation ability), which increased the sucrose concentration in the leaves to support the reproductive function, along with enhanced anti-oxidative capacity and osmo-protectants’ production, which were significantly more in cold-stressed plants, grown from cold-primed seeds, compared to the controls. Our findings in this regard are novel and suggest an effective strategy to enhance cold tolerance in chickpea.

Genome-wide transcriptome analysis reveals the molecular mechanism of high temperature-induced floral abortion in Litchi chinensis

BackgroundWarm winter and hot spring attributed to global warming affected floral development and may induce floral abortion, resulted in poor flowering in litchi. To identify genes potentially involved in litchi floral abortion, six RNA-sequencing (RNA-Seq) libraries of the developing panicles (DPs) under low temperature (LT) conditions and the shrinking panicles (SPs) under high temperature (HT) conditions were constructed.Results3.07–8.97 × 106 clean reads were generated. Digital expression of the DPs with that of the SPs was compared. As a result, 1320 up-regulated and 981 down-regulated differentially expressed genes (DEGs) were identified. From the enriched GO-term, 54 temperature responsive DEGs, 23 hormone homeostasis- or biosynthesis-related DEGs, 137 hormone signal transduction or responsive DEGs, and 18 flowering-related DEGs were identified. Partial Least Squares Structural Equation Modeling (PLS-SEM) analysis indicated that the effects of hormone-related DEGs on NACs, MYBs, WRKYs were stronger than that on flowering-related DEGs. Expression pattern analysis of the inflorescence in ‘Nuomici’ and ‘Huaizhi’ under LT and HT conditions showed that genes homologous to AIL6 (LcAIL6), LHY (LcLHY), MED16 (LcMED16), SKIP20 (LcSKIP20), POD20 (LcPOD20) in the two cultivars had similar expression trends.ConclusionThis study elucidated the transcriptome in the HT-induced floral abortion and identified key genes involved in the process. NACs, MYBs, WRKYs may act as central players involved in the HT-induced floral abortion underlying hormonal control. Increased transcript in LcLHY, LcMED16, LcSKIP20, LcPOD20 and decreased transcript in LcAIL6 might be related to the inhibition of floral development. Our studies provided potential genes for the future molecular breeding of new cultivars that can reduce floral abortion under warm climates, and a novel clue to reveal the relationship of biological processes based on the RNA-seq data using PLS-SEM.

Identification of Genes Involved in Low Temperature-Induced Senescence of Panicle Leaf in Litchi chinensis.

Warm winters and hot springs may promote panicle leaf growing and repress floral development. To identify genes potentially involved in litchi panicle leaf senescence, eight RNA-sequencing (RNA-Seq) libraries of the senescing panicle leaves under low temperature (LT) conditions and the developing panicle leaves under high temperature (HT) conditions were constructed. For each library, 4.78–8.99 × 106 clean reads were generated. Digital expression of the genes was compared between the senescing and developing panicle leaves. A total of 6477 upregulated differentially expressed genes (DEGs) (from developing leaves to senescing leaves), and 6318 downregulated DEGs were identified, 158 abscisic acid (ABA)-, 68 ethylene-, 107 indole-3-acetic acid (IAA)-, 27 gibberellic acid (GA)-, 68 cytokinin (CTK)-, 37 salicylic acid (SA)-, and 23 brassinolide (BR)-related DEGs. Confirmation of the RNA-Seq data by quantitative real-time PCR (qRT-PCR) analysis suggested that expression trends of the 10 candidate genes using qRT-PCR were similar to those revealed by RNA-Seq, and a significantly positive correlation between the obtained data from qRT-PCR and RNA-Seq were found, indicating the reliability of our RNA-Seq data. The present studies provided potential genes for the future molecular breeding of new cultivars that can induce panicle leaf senescence and reduce floral abortion under warm climates.

Inferring vascular architecture of the wheat spikelet based on resource allocation in the branched headt (bht-A1) near isogenic lines.

Substantial genetic and physiological efforts were made to understand the causal factors of floral abortion and grain filling problem in wheat. However, the vascular architecture during wheat spikelet development is surprisingly under-researched. We used the branched headt near-isogenic lines, FL-bht-A1-NILs, to visualise the dynamics of spikelet fertility and dry matter accumulation in spikelets sharing the same rachis node (henceforth Primary Spikelet, PSt, and Secondary Spikelet, SSt). The experiment was conducted after grouping FL-bht-A1-NILs into two groups, where tillers were consistently removed from one group. Our results show differential spikelet fertility and dry matter accumulation between the PSt and SSt, but also showed a concomitant improvement after de-tillering. This suggests a tight regulation of assimilate supply and dry matter accumulation in wheat spikelets. Since PSt and SSt share the same rachis node, the main vascular bundle in the rachis/rachilla is expected to bifurcate to connect each spikelet/floret to the vascular system. We postulate that the vascular structure in the wheat spikelet might even follow Murray's law, where the wide conduits assigned at the base of the spikelet feed the narrower conduits of the distal florets. We discuss our results based on the two modalities of the vascular network systems in plants.

Distribución espacial de las poblaciones de huevos de Bactericera cockerelli Sulc. en el cultivo de tomate de cáscara (Physalis ixocarpa Brot.)

La producción de tomate de cáscara ha sufrido pérdidas económicas del 70% al 80% por la presencia de amarillamiento y aborto floral cuyo agente causal se le atribuye al insecto Bactericera cockerelli Sulc. Las alternativas de control de este insecto han carecido de eficacia, por lo tanto, el objetivo del trabajo fue determinar la distribución espacial de las poblaciones de huevos de B. cockerelli en cuatro parcelas de tomate de cáscara, por medio de la geoestadística, en Luvianos, Estado de México en el año 2016-2017. Se determinó el semivariograma experimental para ajustarse a un modelo teórico (esférico, exponencial o gaussiano) a través de los programas Variowin 2.2, su ajuste se validó con el método de validación cruzada y se obtuvieron los mapas de agregación de la plaga a través del Krigeado ordinario con el programa Surfer 9.0. Los resultados demostraron que las poblaciones de huevos de B. cockerelli presentan una distribución de tipo agregada, que fue corroborada por los mapas de densidad. Las infestaciones no se presentaron en el 100% de la superficie de las parcelas experimentales, lo cual resulta interesante para dirigir las medidas de control sobre áreas específicas de infestación.

Genome-wide association analyses of plant growth traits during the stem elongation phase in wheat.

SummaryOne of the primary objectives of wheat breeding was to increase grain yield. Floral abortion during the stem elongation phase (SEP) leads to a loss of more than 50% of the grain number potential. In this study, we quantified 75 plant growth‐associated traits at seven stages during the SEP and mapped 15 696 single nucleotide polymorphism (SNP) markers in 210 accessions of wheat (Triticum aestivum). Our genomewide association study identified trait‐associated SNPs that are shared among various stages of the SEP, as well as SNPs that are shared between plant growth traits and grain yield in the field. The genomic selection analysis shows variation among the prediction abilities of various traits and stages. Furthermore, we found that the allelic variants of Ppd‐D1 (chromosome 2D) and Rht‐D1 (chromosome 4D) loci affect some plant growth traits (e.g. leaf area and spike length). These results have identified a narrow time window within the SEP in which plant growth traits can be manipulated to alter grain yield. This suggests that there may be multiple ways to regulate plant growth during the SEP, to ultimately influence grain number in wheat.

Etiología de la pudrición de cormos de gladiolo en almacén en Cuautla Morelos, México

<p>Las ventajas de México como productor florícola recaen en su diversidad de climas y su cercanía al mercado norteamericano. Actualmente la exportación de flores y plantas ha quedado consolidada, tal como es el caso del gladiolo al estar libre de arancel. Los principales estados productores son Puebla, Estado de México y Morelos. La producción comercial de la flor de corte de gladiolo se inicia a través de la plantación del cormo; el cual es afectado por diversos patógenos que ocasionan su pudrición, como los del género <em>Penicillium</em> que ataca durante el almacenamiento, provocando desarrollo limitado de raíces y aborto floral. Éste<em> </em>provoca infecciones a través de heridas y sitios de ruptura; se encuentra presente en un 90% de material vegetal aparentemente sano. Los objetivos de este trabajo fueron aislar e identificar cultural, morfológica y molecularmente, así como realizar pruebas de patogenicidad para determinar las especies de <em>Penicillium</em> causantes de la pudrición. A partir de cormos variedad GrandPrix® (10/12) con diferentes niveles de deterioro morfológico y de acuerdo a una escala hedónica visual de siete puntos. Se aisló e identificó a <em>P. verrucosum</em> Dierckx y <em>P. rugulosum</em> Thom como causantes de la pudrición de cormos, este último reportado por primera vez como fitopatógeno en gladiolo.</p>

High Night Temperatures During the Floral Bud Stage Increase the Abscission of Reproductive Structures in Cotton

AbstractCotton‐producing regions throughout the world often experience high night temperatures (HNTs), affecting flowering and yield in cotton (Gossypium hirsutum). The objective of this study was to quantify the effects of high nighttime temperatures on the physiological and biochemical characteristics of cotton during the floral bud and flowering stages. Growth chamber experiments were conducted in 2011–2012 and treatments included a control (day/night temperature of 32/24 °C) and two HNT treatments (32/29 °C from 8:00 pm to 12:00 am) for 3 weeks from the beginning of each phenological stage, i.e., first floral bud (B1) and first flower (F1). The results indicated that increased night temperatures (NTs) during the floral bud and flowering stages increased the rate of flower production per plant. However, no increase was observed in the final number of reproductive structures because the rate of floral abortion also increased for both treatments compared to the control. Additionally, the increase in night temperature during the floral bud stage reduced the sucrose content in the flower, resulting in decreased pollen viability and premature abortion of reproductive structures while the onset of flowering period was also delayed and lower accumulation of reproductive dry matter was observed. HNTs during the flowering stage reduced the number of seeds per locule and the number of seeds per boll. In general, higher than optimum NTs affected sucrose metabolism of the cotton flower and consequently its pollen viability. As a result the flowering period was delayed and a reduction in reproductive dry matter accumulation was observed due to premature abortion of reproductive structures. Finally, cotton is more sensitive to HNT at floral bud stage and this finding may be important to adjust cotton planting date, management and breeding.

First register of occurrence of Frankliniella schultzei (Trybom, 1910) (Thysanoptera: Thripidae) in Cowpea (Vigna unguiculata (L.) Walp.) in the state of Piauí, Brazil

(L.) Walp.), known in the Brazilian northeast as “Feijao-de-corda” is a rustic Leguminosae with great productive capacity, cultivated mainly by small and average farmers in northern and northeastern Brazil. In these regions, this food constitutes the main source of protein for the population, thereby constituting great social importance. Cowpea is susceptible to many pests, which can cause considerable losses in its productivity. Among these pests are thrips (Thysanoptera), which still remain unknown by most of the producers and are responsible for floral abortion, causing losses in farming (Freire Filho et al, 2005). These insects have become important pests in Cowpea in the last few years, mainly in drought periods (Andrade Junior et al., 2002), especially by the middle of the year, when the weather is hot and the humidity rate is low in the Brazilian northeast. Thrips attack flowers more often, provoking floral abortion. In high numbers, they can also attack leaves and branches. However, attack on flowers causes greater damage and, as they hide inside the petals, the action of insecticides can be made difficult (Freire Filho et al., 2005).Throughout the world, 6000 species of thrips are known (Mound and Morris, 2007). Five hundred and twenty of them are recorded in Brazil (Monteiro et al

Changes in duration of developmental phases of durum wheat caused by breeding in Spain and Italy during the 20th century and its impact on yield.

Although the apical development of wheat has been widely described, studies analysing how genetic breeding over the 20th century influenced the developmental phases and its consequences on yield generation are lacking, especially for durum wheat under field conditions in Mediterranean environments. The aims of this study were to analyse the effects of breeding in Spain and Italy on crop development during the last century, to determine whether or not breeding significantly altered the developmental phases between sowing and maturity, and to evaluate the importance of each phase in determining the number of grains per spike of durum wheat (Triticum durum) cultivars representing the germplasm grown throughout the 20th century in Spain and Italy. Eight field experiments were carried out during 4 years in two contrasting latitudes (Lleida and Granada, Spain). Plant material consisted of 24 durum wheat cultivars (12 Italian and 12 Spanish) grown throughout the 20th century in Spain and Italy. In Spanish materials, breeding reduced the duration of the period from sowing to anthesis, placing the grain-filling period in better conditions. In those cultivars, the sub-phase sowing-terminal spikelet formation was reduced while the duration of the period from booting to anthesis was increased. The number of grains per spike increased by 23 % from old to modern cultivars, by changes in the number of grains per spikelet in both Spanish and Italian cultivars. Floral abortion from booting to anthesis diminished by 24 % from old to modern cultivars, and grain setting increased by 13 %. The results suggest that breeding reduced not only plant height, but also the time to anthesis. By extending the duration of the phase from booting to anthesis, which was associated with an increase in spike dry weight and grains per spike, it suggests that future increases in spike fertility could be achieved by enlarging that phase.

Sucrose synthase and acid invertase activities in relation to the floral structures abortion in pepper (Capsicum annuum L.) grown under low night temperature

Sucrose synthase and acid invertase activities in relation to the floral structures abortion in pepper (Capsicum annuum L.) grown under low night temperature

Detection and Identification of a Group 16SrIII-Related Phytoplasma Associated with Coffee Crispiness Disease in Colombia.

Coffee crispiness ("crespera"), a disease of uncertain etiology, has been endemic in coffee (Coffea arabica L.) plantations in Colombia for at least 60 years. Symptoms typically consist of bud proliferation, abundant short and narrow leaves, phyllody, floral abortion, monospermic fruit, and dwarfing of plants. In severe cases, coffee crispiness disease (CCD) can affect production significantly. In this study, association of a phytoplasma with CCD was indicated by the accumulation of Diene's stain, or 4', 6-diamidino-2-phenylindole fluorescence, only in phloem of affected plant tissues. The presence of polymorphic phytoplasma cells in phloem sieve tube elements was confirmed by transmission electron microscopy. The disease was transmitted successfully by grafting symptomatic shoots from CCD-affected C. arabica plants onto young, healthy rootstocks; however, symptoms failed to develop after mechanical inoculation of young plants with extracts derived from diseased plant tissues. A nested polymerase chain reaction (PCR) assay employing primer pairs P1/P7 followed by FU5/rU3 amplified a 16S ribosomal DNA product (941 bp) exclusively from DNA of diseased plants. Sequence and phylogenetic analysis of the nested PCR product identified the CCD phytoplasma as a new strain member of group 16SrIII (X-disease group). This is the first report of a phytoplasma infecting coffee plants.