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We performed active and passive measurements of diurnal cycles of chlorophyll fluorescence on potato crops at canopy level in outdoors conditions for 26 days. Active measurements of the stationary fluorescence yield (Fs) were performed using Ledflex, a fluorescence micro-LIDAR described in Moya et al. (Photosynth Res 142:1–15, 2019), capable of remote measurements of chlorophyll fluorescence under full sun-light in the wavelength range from 650 to 800 nm. Passive measurements of solar-induced fluorescence (SIF) fluxes were performed with Spectroflex, an instrument based on the method of filling-in in the O2A and O2B absorption bands at 760 nm (F760) and 687 nm (F687), respectively.Diurnal cycles of Fs showed significant variations throughout the day, directly attributed to changes in photosystem II yield. Contrasting patterns were observed according to illumination conditions. Under cloudy sky, Fs varied in parallel with photosynthetically active radiation (PAR). By contrast, during clear sky days, the diurnal cycle of Fs showed a “M” shape pattern with a minimum around noon.F687 and F760 showed different patterns, according to illumination conditions. Under low irradiance associated with cloudy conditions, F687 and F760 followed similar diurnal patterns, in parallel with PAR. Under high irradiance associated with clear sky we observed an increase of the F760/F687 ratio, which we attributed to the contributions in the 760 nm emission of photosystem I fluorescence from deeper layers of the leaves, on one end, and by the decrease of 687 nm emission as a result of red fluorescence re-absorption, on the other end.We defined an approach to derive a proxy of fluorescence yield (FYSIF) from SIF measurements as a linear combination of F687 and F760 normalized by vegetation radiance, where the coefficients of the linear combination were derived from the spectral transmittance of Ledflex. We demonstrated a close relationship between diurnal cycles of FYSIF and Fs, which outperformed other approaches based on normalization by incident light.

Ledflex is a fluorometer adapted to measure chlorophyll fluorescence at the canopy level. It has been described in detail by Moya et al. (2019), Photosynthesis Research. https://doi.org/10.1007/s11120-019-00642-9. We used this instrument to determine the effect of water stress on the fluorescence of a fescue field under extreme temperature and light conditions through a 12 days campaign during summer in a Mediterranean area. The fescue field formed part of a lysimeter station in "las Tiesas," near Albacete-Spain. In addition to the fluorescence data, the surface temperature was measured using infrared radiometers. Furthermore, "Airflex," a passive fluorometer measuring the filling-in of the atmospheric oxygen absorption band at 760 nm, was installed in an ultralight plane and flown during the most critical days of the campaign. We observed with the Ledflex fluorometer a considerable decrease of about 53% of the stationary chlorophyll fluorescence level at noon under water stress, which was well correlated with the surface temperature difference between the stressed and control plots. Airflex data also showed a decrease in far-red solar-induced fluorescence upon water stress in agreement with surface temperature data and active fluorescence measurements after correction for PS I contribution. Notwithstanding, the results from airborne remote sensing are not as precise as in situ active data.

Resumen La cantidad de energía solar absorbida por una hoja es en gran parte función de la concentración foliar de los pigmentos fotosintéticos. Por lo tanto, bajas concentraciones de clorofila pueden limitar el potencial fotosintético y por consiguiente la síntesis de compuestos primarios de una planta. En este trabajo se describe un método no destructivo para estimar las concentraciones de clorofila de foliolos de los cultivares de papa: SA-2563, Pumamaqui y Purranca, basada en la interacción entre la luz y la vegetación, que utiliza la primera derivada de sus respectivos espectros de reflectancia. Como referencia, se utilizaron las unidades SPAD adquiridas por un medidor de clorofila SPAD-502 que fue previamente validado. Correlaciones mayores al 90% entre las amplitudes de las señales obtenidas de derivar los espectros de reflectancia de foliolos en longitudes de onda alrededor de 720 nm y las concentraciones de clorofila medidas con un SPAD-502, evidencian el potencial del método basado en reflectancia de la vegetación como indicador seguro para estimar parámetros bioquímico-fisiológicos de las plantas. Abstract The amount of solar energy absorbed by plants is largely a function of the foliar concentration of photosynthetic pigments. Consequently, low concentrations of chlorophyll can directly limit the photosynthetic potential and thus the primary production of plants. This study describes a non-destructive method aiming to estimate the chlorophyll concentrations on potato leaves from the cultivars SA-2563, Pumamaqui and Purranca. This method is based on the interaction between light and vegetation and uses the first derivative of spectral reflectance from the crop canopy. For reference, we used the SPAD units obtained with a previously validated SPAD-502 chlorophyll meter. We found correlations greater than 90% between the amplitudes of signals obtained by deriving the spectral reflectance of leaves at wavelength about 720 nm and the chlorophyll concentrations obtained by the SPAD-502. Overall, this study showed the potential of techniques based on vegetation reflectance as robust indicators for estimating plant biochemical-physiological parameters.

A new record of the powdery mildew Phyllactinia chubutiana, nom. cons. (= Oidium insolitum, Ovulariopsis insolita) was documented on pearl berry [Vallesia glabra (Cav.) Link]. No teleomorph was observed. This novel record was identified as a member of Ovulariopsis, based on the morphological characteristics of the anamorph (hyphae, conidiophores, and conidia), and its hemi-endophytic mycelium in V. glabra correspond to P. chubutiana, nom. cons. A Phyllactinia-specific primer pair was designed for the ITS region of the nuclear rDNA. Phylogenetic analyses confirmed the identity of the powdery mildew specimens found in V. glabra in Sinaloa, Mexico. This is the first ever report of this powdery mildew in V. glabra, and the second report world-wide on a member of the Apocynaceae.

The Human Dopamine Transporter (hDAT) plays an essential role in modulating the Influx/Efflux of dopamine, and it is involved in the mechanism of certain neurodegenerative diseases such as Parkinson’s disease. Macromolecules adopt many conformations in solution depending on their structure and shape, which determine their dynamics and function. In this context, several studies have reported important meta-states for Dopamine transport: outward-facing open state (OFo), the outward-facing closed state (OFc), the holo-occluded state closed (holo), and the inward-facing open state (IFo). Furthermore, experimental assays have shown that different phosphorylation conditions can affect the rate of dopamine absorption. This work presents a protocol using hybrid simulation methods to study the conformational dynamics and stability of meta-states of hDAT under different phosphorylation states. With this protocol, we explored the conformational space of hDAT, identified the meta-states, and evaluated the free energy differences and the transition probabilities between them in each of the phosphorylation cases. We also presented the conformational changes and correlated them with those described in the literature. The results suggest that the phosphorylation corresponding to NP-333, where (all sites [Ser/Thr](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4380854/) from residue 2 to 62 and residue 254 to 613 are phosphorylated, except residue 333) is the one that would affect dopamine transport the most, corroborating the experimental results. Furthermore, our results showed that just single phosphorylation/dephosphorylation could alter intrinsic protein motions affecting the sampling of one or more meta-states necessary for dopamine transport. In this sense, the modification of phosphorylation influences protein movements and conformational preferences, affecting the stability of meta-states and the transition between them and, therefore, the transport.

Agricultural UAV-based remote sensing tools to facilitate decision-making for increasing productivity in developing countries were developed and tested. Specifically, a high-quality multispectral sensor and sophisticated-yet-user-friendly data processing techniques (software) under an open-access policy were implemented. The multispectral sensor—IMAGRI-CIP—is a low-cost adaptable multi-sensor array that allows acquiring high-quality and low-SNR images from a UAV platform used to estimate vegetation indexes such as NDVI. Also, a set of software tools that included wavelet-based image alignment, image stitching, and crop classification have been implemented and made available to the remote sensing community. A validation field experiment carried out at the International Potato Center facilities (Lima, Peru) to test the developed tools is reported. A thorough comparison study with a wide-used commercial agricultural camera showed that IMAGRI-CIP provides highly correlated NDVI values (R2≥ 0.8). Additionally, an application field experiment was conducted in Kilosa, Tanzania, to test the tools in smallholder farm settings, featuring high-heterogeneous crop plots. Results showed high accuracy (> 82%) to identify 13 different crops either as mono-crop or as mixed-crops.

This study aimed at estimating carbon footprint (CF) and assessing mitigation options for selected tropical crops using excel-based models, parameterized with data collected through closed-ended questions questionnaires, combined with a reference trial (RT). Most of the estimates using structured interviews were similar to those measured in the RT and the literature. Total average emission intensities ranged from 24 to 290 kg CO2eq·Mg−1, where the extreme values corresponded to cassava in the RT (24 kg CO2eq·Mg−1) and maize in interviewed farmers in Barranca province (290 kg CO2eq·Mg−1). Overall, fertilizer production and application contributed to 77% of total greenhouse gas (GHG). Transportation generated emissions comparable to field estimates. Farm emissions can be reduced in 17 to 27% with incorporation of mitigation practices. The methodology used in this study constitute a useful and easily applicable tool to assess ex-ante the impact of policies and decisions on CF under farm conditions. It can also be used by different stakeholders for different purposes; including but not limited to: label products offered in the market with GHG emission estimates, make decisions to regulate the emissions in the agricultural sector, and to enable farmers to negotiate prices and incentives for environmental preservation with quantitative information. Keywords: Peru, Emissions, Maize, Sweet potato, Cassava, Fertilizers

Bacillus circulans E9 (now known as Niallia circulans) promotes plant growth-producing indole-3-acetic acid (IAA), showing potential for use as a biofertilizer. In this work, the use of a low-cost medium containing industrial substrates, soybean, pea flour, Solulys, Pharmamedia, yeast extract, and sodium chloride (NaCl), was evaluated as a substitute for microbiological Luria Broth (LB) medium for the growth of B. circulans E9 and the production of IAA. In Erlenmeyer flasks with pea fluor medium (PYM), the maximum production of IAA was 7.81 ± 0.16 μg mL

A biofungicide is a natural product that can be derived from various sources such as, among others, microorganisms, higher plants, animal products, phytochemicals, semiochemicals, and antagonist microorganisms. One of the most important approaches for the production of biofungicides is the combination of biocontrol agents. This study showed the inhibition growth of Alternaria alternata and Fusarium solani treated with cell-free extracts of P. fluorescens. Using thin-layer chromatography and plate assays it was also demonstrated that the cell-free extracts of P. fluorescens contained siderophores and derivates of 4-diacetylphloroglucinol and phenazine. Moreover, the combination of cell-free extracts of P. fluorescens and chitosan [50–1.5% (v/v)] had a synergistic effect since they notably inhibited the mycelial growth of A. altenata and F. solani. Various morphological alterations to the mycelia and conidia of the treated fungi as a result of this combination were also observed. The present study could be a starting point to control other fungal phytopathogens using different cell-free extracts and chitosan as biocontrol agents.

La soya es una de las leguminosas más importantes en el mundo. En años recientes en el norte de Sinaloa se ha observado incidencia de mancha foliar en la etapa de llenado de grano e inicio de la madurez. El objetivo del presente trabajo fue identificar el agente causal de esta enfermedad. Se colectaron muestras de foliolos sintomáticos en ocho lotes comerciales de soya, de los cuales se obtuvieron ocho aislados fúngicos, y se identificaron morfológica y molecularmente. Se realizaron pruebas de patogenicidad en plantas de soya var. Nainari y se confirmaron los postulados de Koch, mediante el reaislamiento de los aislados originales. Los análisis morfológicos determinaron al género Curvularia asociado a la mancha foliar de la soya. El análisis filogenético del gen gadph permitió la identificación de Curvularia ahvazensis, C. muehlenbeckiae, C. spicifera y Curvularia sp. Estas especies resultaron patogénicas en soya var. Nainari mostrando variación en virulencia, pues el área foliar afectada varió de 3 a 31%. Los resultados abren nuevas líneas de investigación relacionadas con el impacto de la enfermedad en el rendimiento y calidad de la cosecha de la soya en Sinaloa.

Canopy temperature (CT) as a surrogate of stomatal conductance has been highlighted as an essential physiological indicator for optimizing irrigation timing in potatoes. However, assessing how this trait could help improve yield prediction will help develop future decision support tools. In this study, the incorporation of CT minus air temperature (dT) in a simple ecophysiological model was analyzed in three trials between 2017 and 2018, testing three water treatments under drip (DI) and furrow (FI) irrigations. Water treatments consisted of control (irrigated until field capacity) and two-timing irrigation based on physiological thresholds (CT and stomatal conductance). Two model perspectives were implemented based on soil water balance (P1) and using dT as the penalizing factor (P2), affecting the biomass dynamics and radiation use efficiency parameters. One of the trials was used for model calibration and the other two for validation. Statistical indicators of the model performance determined a better yield prediction at harvest for P2, especially under maximum stress conditions. The P1 and P2 perspectives showed their highest coefficient of determination (R2) and lowest root-mean-squared error (RMSE) under DI and FI, respectively. In the future, the incorporation of CT combining low-cost infrared devices/sensors with spatial crop models, satellite image information, and telemetry technologies, an adequate decision support system could be implemented for water requirement determination and yield prediction in potatoes.

Chitosan is a biopolymer with various favorable properties (biotic/abiotic stress mitigation, qualitative improvement, bio-fertilizer, bio-stimulant and postharvest management) to meet multiple agricultural objectives. Grapevine is an important crop and has an enormous impact on the world’s economy due to its derived products, notably the different wine styles. In viticulture, chitosan application made significant developments towards higher contents of beneficial metabolites in grape berries as well as stress and postharvest management during recent decades, although the reports are limited. Recent investigations by our group demonstrated chitosan as a potential elicitor molecule at a molecular level and opened the possibility to use chitosan for trunk disease management; moreover, there are not yet any methods to combat trunk diseases in grapevine. The present viewpoint aimed to summarize the different aspects of chitosan application in grapevine in facilitating the development of inclusive and more integrated sanitary viticulture practices in a sustainable manner.

The cuticle is a critical barrier covering the surface of plant aerial organs. It is associated with important physiological and biological fruit traits, but few studies on this structure have been conducted in tropical fruit such as mango. Here, we have reported on a detailed investigation on the cuticle of six cultivars of mangoes (Kent, Tommy Atkins, Manila, Ataulfo, Criollo and Manililla), by combining several advanced microscopy tools and chemical analyses. All mango cultivars exhibited high variability in cuticle architecture, epicuticular wax layer (EWL) deposition, and different pattern of changes in cutin monomers. Mango cultivars exhibited different water transpiration rates, firmness and fruit quality appearance during postharvest shelf life (PSL), which could not be simply explained by an isolated cuticle structural feature. However, mango cuticles of premium mangos such as Kent, Tommy and Ataulfo displayed prominent cuticle deposition during PSL compared to other cultivars. Tommy fruit with large wax deposition, marginal number of lenticels and prominent cuticle thickening during PSL, exhibited lower percentage of weight lost by transpiration and less visual deterioration of all mango cultivars studied. In contrast, Criollo fruit, with a significant number of lenticels, small EWL, and marginal cuticle thickening during PSL were associated with the highest rate of water transpiration, fruit deterioration, and abscisic acid content. Our results partially explain the resistance patterns to fruit fly attack documented in earlier studies, clearly showing that cultivars such as Criollo are highly susceptible whereas Tommy, Kent, and Ataulfo are resistant because of the cuticle characteristics described in this study.

Cicer microphyllum Benth. is a wild legume that is adapted to the extremely adverse climatic conditions of the cold Himalayan deserts. This rare species is a crop wild relative (CWR) that could be used for chickpea (Cicer arietinum L.) breeding programs to improve abiotic stress tolerance. However, the availability of C. microphyllum biological material is very limited due to its high altitude and remote location. These factors make in vitro plant tissue culture an excellent alternative for the conservation and propagation of this species. In this study, an efficient and reproducible in vitro regeneration protocol was established for C. microphyllum. This process enabled the regeneration of multiple shoots through indirect organogenesis from excised embryos. In addition, the effects of combinations of auxin and cytokinin concentrations in Murashige and Skoog (MS) medium were tested. The highest percentage of callus induction was observed on MS with α-Naphthaleneacetic acid (NAA) and 6-Benzylaminopurine (BAP), and the addition of AgNO3 to MS with NAA and BAP significantly improved shoot morphogenesis. The highest root percentage was observed on half-strength MS with Indole-3-butyric acid (IBA). Regenerated plantlets had a 65% survival rate 25 d after transplanting to garden soil, vermiculite, and vermicompost (1:1:1) potting mix. This protocol can be routinely used in large-scale propagation and possibly in germplasm conservation of this rare and important CWR species for additional use in chickpea breeding programs.

Mezcal je destilat koji se proizvodi spontanom fermentacijom mošta dobivenog kuhanjem stabljika biljke Agave spp. i prešanjem dobivene smjese. Mošt agave sadržava velike količine fruktoze i fenolnih spojeva, a fermentacija se najčešće odvija pri stresnim i nekontroliranim uvjetima. Kvasci koji mogu rasti u takvim uvjetima obično imaju povoljna biološka i industrijska svojstva koja ih čine otpornijim, poput svojstva flokulacije. U ovom je radu sedam sojeva kvasca Saccharomyces cerevisiae izoliranih iz mošta agave izloženo temperaturama od 10 do 40 °C i uzgojeno u podlogama u prisutnosti fruktoze ili glukoze. Brojanjem kolonija u tzv. „microdrop“ testu potvrđeno je da su kvasci koji su rasli u podlozi s dodatkom fruktoze imali veću otpornost na stres uzrokovan niskom temperaturom (10 °C), u usporedbi s kvascima uzgojenim pri 40 °C. Soj kvasca koji je najbolje podnio stres (Sc3Y8) i komercijalni vinski kvasac (Fermichamp) uzgojeni su u tekućoj podlozi za fermentaciju i dugotrajno izloženi toplinskom stresu, radi određivanja njihove sposobnosti flokulacije. Tijekom fermentacije u podlozi s fruktozom povećalo se nakupljanje metabolita na kraju procesa, osobito pri 40 °C, te je proizvedeno 2,3 puta više glicerola (8,6 g/L), 1,3 puta više etanola (43,6 g/L) i 3,4 puta više octene kiseline (7,3 g/L) nego tijekom fermentacije u podlozi s glukozom. Pomoću konfokalnog mikroskopa utvrđene su morfološke promjene u kvascu, kao što su agregacija stanica i prisutnost ožiljaka na stijenci nastalih uslijed pupanja kvasca, osobito u soju Sc3Y8 izloženom temperaturi od 40 °C. Potvrđeno je da ovaj soj kvasca za proizvodnju pića mezcal flokulira u prisutnosti iona kalcija. Analizom ekspresije gena FLO1, FLO5 i FLO11 uključenih u regulaciju flokulacije potvrđeno je da je došlo do indukcije transkripcije u oba soja kvasca S. cerevisiae, naročito gena FLO5 u soju Sc3Y8., Mezcal is a distillate produced by spontaneous fermentation of the must obtained from stalks of Agave spp. plants that are cooked and pressed. Agave must contains a high amount of fructose and phenolic compounds, and fermentation usually occurs under stressful (and uncontrolled) environmental conditions. Yeasts capable of growing under such conditions usually display advantageous biological and industrial traits for stress tolerance such as flocculation. In this study, seven Saccharomyces cerevisiae strains isolated from mezcal must were exposed to temperatures ranging between 10 and 40 °C, and to different sugar sources (fructose or glucose). Yeasts grown in fructose increased their stress tolerance, determined by colony count in a microdrop assay, under low temperature (10 °C) compared to the growth at 40 °C on solid cultures. The most stress-tolerant mezcal strain (Sc3Y8) and a commercial wine (Fermichamp) strain, used as control, were grown under fermentation conditions and exposed to long-term temperature stress to determine their performance and their potential for flocculation. Compared to glucose, fermentation on fructose increased the metabolite accumulation at the end of culture, particularly at 40 °C, with 2.3, 1.3 and 3.4 times more glycerol (8.6 g/L), ethanol (43.6 g/L) and acetic acid (7.3 g/L), respectively. Using confocal microscopy analysis, we detected morphological changes such as aggregation and wall recognition at the level of budding scars in yeast, particularly in the Sc3Y8 strain when it was exposed to 40 °C. The analysis confirmed that this mezcal strain was positive for flocculation in the presence of Ca2+ ions. Analysis of FLO1, FLO5 and FLO11 gene expression implicated in flocculation in both Saccharomyces strains showed a strong transcriptional induction, mainly of the FLO5 gene in the mezcal Sc3Y8 strain.

Resumen: En N. Kazantzakis la religión tuvo una gran preocupación personal y literaria. Varias de sus obras pasan por el tema de la fe. Sin embargo, para Kazantzakis la fe religiosa se constituye en un problema filosófico. Quizá en su obra hay varias respuestas para el mismo y gran problema.

Every year, more than 500,000 new cases of cervical cancer are reported, making it the fourth leading cause of cancer globally. Although human papillomavirus (HPV) vaccines show promise as a protective measure, HPV-related cancers remain a public health problem since the vaccines, which are only specific to certain viral types, are unavailable for mass distribution. Furthermore, the effects of toxicity following ionizing radiation therapy have reoriented views toward the search for radiosensitizers that can reduce toxicity as a consequence of decreased radiation doses. Here, we isolated ergosterol peroxide (EP) from Pleurotus ostreatus and purified it to test its potential effects in vitro. We thus observed that a gradual increase in EP dose correlates with a loss of viability in HeLa and CaSki cervical cell lines. Dose/response curves were constructed using cervical cancer cell lines, as well as normal human peripheral blood mononuclear cells. The selectivity of EP in human lymphocytes and cervical cancer cell lines was tested, and no toxicity was found in normal cells. A combination of treatments revealed a radiosensitizer effect in HeLa cells, when measuring the exposure to EP followed by irradiation with 137Cs. Our findings suggest that EP may be effective as a radiosensitizer in treating cervical cancer.

Somatic embryogenesis (SE) is a valuable model for understanding the mechanism of plant embryogenesis and a tool for the mass production of plants. However, establishing SE in avocado has been complicated due to the very low efficiency of embryo induction and plant regeneration. To understand the molecular foundation of the SE induction and development in avocado, we compared embryogenic (EC) and non-embryogenic (NEC) cultures of two avocado varieties using proteomic and metabolomic approaches. Although Criollo and Hass EC exhibited similarities in the proteome and metabolome profile, in general, we observed a more active phenylpropanoid pathway in EC than NEC. This pathway is associated with the tolerance of stress responses, probably through the reinforcement of the cell wall and flavonoid production. We could corroborate that particular polyphenolics compounds, including p-coumaric acid and t-ferulic acid, stimulated the production of somatic embryos in avocado. Exogen phenolic compounds were associated with the modification of the content of endogenous polyphenolic and the induction of the production of the putative auxin-a, adenosine, cellulose and 1,26-hexacosanediol-diferulate. We suggest that in EC of avocado, there is an enhanced phenylpropanoid metabolism for the production of the building blocks of lignin and flavonoid compounds having a role in cell wall reinforcement for tolerating stress response. Data are available at ProteomeXchange with the identifier PXD019705.

Crop efficiencies associated with intercepted radiation, conversion into biomass and allocation to edible organs are essential for yield improvement strategies that would enhance genetic properties to maximize carbon gain without increasing crop inputs. The production of 20 potato landraces&mdash, never studied before&mdash, was analyzed for radiation interception ( &epsilon, i ), conversion ( &epsilon, c ) and partitioning ( &epsilon, p ) efficiencies. Additionally, other physiological traits related to senescence delay (normalized difference vegetation index (NDVI) s l p ), tuberization precocity ( t u ), photosynthetic performance and dry tuber yield per plant (TY) were also assessed. Vegetation reflectance was remotely acquired and the efficiencies estimated through a process-based model parameterized by a time-series of airborne imageries. The combination of &epsilon, i and &epsilon, c , closely associated with an early tuber maturity and a NDVI s l p explained 39% of the variability grouping the most productive genotypes. TY was closely correlated to senescence delay (r P e a r s o n = 0.74), indicating the usefulness of remote sensing methods for potato yield diversity characterization. About 89% of TY was explained by the first three principal components, associated mainly to t u , &epsilon, c and &epsilon, i , respectively. When comparing potato with other major crops, its &epsilon, p is very close to the theoretical maximum. These findings suggest that there is room for improving &epsilon, c to enhance potato production.

Mycotoxins from the Fusarium genus are widely known to cause economic losses in crops, as well as high mortalities rates among immunocompromised humans. However, to date, no correlation has been established for the ability of Fusarium to cause cross-kingdom infection between plants and humans. The present investigation aims to fill this gap in the literature by examining cross-kingdom infection caused by Furasium strains isolated from non-immunocompromised or non-immunosuppressed humans, which were subsequently reinfected in plants and on human tissue. The findings document for the first time cross-kingdom infective events in Fusarium species, thus enhancing our existing knowledge of how mycopathogens continue to thrive in different hosts.

Potatoes&mdash, a global food security and staple crop&mdash, is threatened by dry spells in drought-prone areas. The use of physiological thresholds to save water while maintaining a reasonable tuber yield has been proposed, but their effects on physiological performances and usefulness under different irrigation methods are yet to be evaluated. In this study, photosynthetic traits were monitored to assess the effect of water restriction and rewatering under drip (DI) and furrow (FI) irrigations. The treatments consisted of two maximum light-saturated stomatal conductance (g s _ m a x ) irrigation thresholds (T2: 0.15 and T3: 0.05 mol H 2O m &minus, 2 s &minus, 1 ) compared with a fully irrigated control (g s _ m a x &gt, 0.3 mol H 2O m &minus, 1 ). DI used less water than FI but promoted early senescence and low percentage of maximum assimilation rate (PMA) at late developmental stages. FI caused no yield penalization in T2 and higher recovery of carbon isotope discrimination and PMA than DI. It is suggested that moderate water quantities of early and frequently water pulses in the irrigation, promote short-term water stress memory improvement, senescence delay and more capability of recovery at late stages.

Low radiation is one of the most important factors which limits potential yield in potato. Under humid conditions, the dominance of diffuse radiation not only imposes challenges for radiation use efficiency in crops but also limits the water status surveillance through non-invasive methods like infrared radiometry. This study was carried out in the humid desert of the Peruvian central coast with the aim to relate maximum stomatal conductance (gs_max, an important water status indicator) with leaf and air temperature (dT) and crop water stress index (CWSI). In a potted trial, gs_max vs. dT were compared along the day in well-irrigated (field capacity) and water restricted (half field capacity) plants. In an additional field experiment, CWSI was validated by testing two irrigation timing treatments with pre-established gs_max threshold (0.15 [T1] and 0.50 [T2] mol H2O m−2 s−1) against a control (frequently irrigated). An acute stomatal closure sensitivity was detected which drove a gs_max fall (gs↓) near the solar noon. The intense stomatal closure caused a dT rise which showed positive higher values (> 2 °C) after gs↓. The significant yield reduction of T1 in relation to the control (− 38.2 ± 10.7%) highlighted that gs_max values > 0.15 must be used to warrant a high potato yield. These findings support the use of CWSI values ≤ 0.3–0.4 as thresholds for an appropriate irrigation in potatoes with assessments taken at around 15:00 hours, time in which plants have accumulated enough radiation allowing an appropriate detection of thermal emission under humid conditions.

China is the largest worldwide potato producer where around half of the crops is planted in the semi-arid region frequently affected by water restriction. While innovative methods are needed for water-saving irrigation methods, the use of low-cost and environmental-friendly technology must be prioritised. In this study, potato production under drip irrigation (DI, commonly adopted to save water) was compared with partial root-zone drying furrow irrigation (PRD) using the same water volume per irrigation, in both methods. Two initiation timings (early and late) were tested under shelter and field conditions, the water supplied during every irrigation being 50% of the crop water demand calculated for furrow full irrigation (FI, as control). The comparison of both methods was done through the assessment of tuber fresh-yield and estimated economic and environmental (carbon footprint and irrigation water use efficiency, WUEi) benefits. Late PRD and DI produced the highest WUEi without significant yield reduction. PRD produced 3.1% higher net benefit than DI with an estimated CO2 emission of 3659 kg ha−1 CO2 (14% lower than DI). The input-output ratio (total input costs/yield output) for PRD was 0.4, which was 10% lower than DI. The study’s results suggested that PRD, with no less than 50% of the water applied in FI per application, not only maintained yield but could also increase revenues while saving water and reducing CO2 emissions, compared to DI. Such results might help reduce the pressure on the water reserves in semi-arid potato-producing areas in China. Notwithstanding, a scaling-up of PRD technology must be tested in those regions to substantiate the findings of this preliminary study.

The Andean region is the most important center of potato diversity in the world. The global warming trend which has taken place since the 1950s, that is 2-3 times the reported global warming and the continuous presence of extreme events makes this region a live laboratory to study the impact of climate change. In this review, we first present the current knowledge on climate change in the Andes, as compared to changes in other mountain areas, and the globe in general. Then, the review describes the ecophysiological strategies to cope and adapt to changes in atmospheric CO2 levels, temperature and soil water availability. As climate change also has a significant effect on the magnitude and frequency of the incidence of pests and diseases, the current knowledge of the dynamics of vectors in the Andean region is discussed. The use of modeling techniques to describe changes in the range expansion and number of insect pest generations per year as affected by increases in temperature is also presented. Finally, the review deals with the use of crop modeling to analyze the likely impact of projected climate scenarios on potato yield and tuber initiation.

According to potato experts from ten Sub-Saharan Africa (SSA) countries working together in a community of practice (CoP) over a 3-years period, potato farmers across SSA can increase their current annual production of 10.8 million metric tons by 140% if they had access to high quality seed along with improved management practices. This paper describes this innovative new methodology tested on potato for the first time, combining modelling and a comprehensive online survey through a CoP. The intent was to overcome the paucity of experimental information required for crop modelling. Researchers, whose data contributed to estimating model parameters, participated in the study using Solanum, a crop model developed by the International Potato Center (CIP). The first finding was that model parameters estimated through participatory modelling using experts’ knowledge were good approximations of those obtained experimentally. The estimated yield gap was 58 Mg ha-1, of which 35 corresponded to a research gap (potential yield minus research yield) and 24 to farmers’ gap (research yield minus farmer’s yield). Over a 6-month period, SurveyMonkey, a Web-based platform was used to assess yield gap drivers. The survey revealed that poor quality seed and bacterial wilt were the main yield gap drivers as perceived by survey respondents.

Expansion of crop production into high-altitude native grasslands is occurring in the Peruvian High-Andes due to climate change and agricultural intensification, with little understanding of the consequences to the ecosystem. The objective of this study was to determine the impact of land-use changes on soil fertility and nutrient cycling to guide future land management. Comparisons were made between native grasslands and two alternative farming systems; the first was a system in which native grassland was replaced by an annual cash crop, maca (Lepidium meyenii Walp.), followed by a long fallow and the second was a long-standing perennial cultivated pasture. There was greater N mineralization, extractable Bray-1 P, and K⁺ in recently converted maca soils relative to adjacent native grassland soils most likely caused by tillage-induced nutrient mineralization and by incorporation of manure and native grassland residue during the first year of land preparation prior to planting maca. Soil fertility, as determined by an ex situ pot trial to measure plant yield, was correlated with plant cover, soil total organic carbon, and water stable aggregates (WSA) under fallow following maca, suggesting that soil erosion might be an issue in the long term. In cultivated pastures, we found an increase in long-term fertility driven primarily by the build-up of soil N and improved soil structure in the perennial grass-legume mixture compared with adjacent native grassland. Responsible management of the Puna agroecosystem requires restoration of plant cover after annual cropping of maca or the establishment of mixed perennial cultivated pasture.

Quarantine measures to prevent insect dispersion include modified atmospheres or hot water treatment (HWT) for mango. The effects of HWT on mango “Ataulfo” at mature-green and ripe stages on gene expression were evaluated by RNA-seq. 27,629 ORF were annotated according to the non-redundant database and most of the changes in gene expression due to the HWT occurred at the mature-green stage with 903 differentially expressed genes (Log2 fold-change ≥ 4, FDR

Soil organic C (SOC), the largest terrestrial C pool, has been shown to be sensitive to agricultural disturbance. In the Andean Puna, agricultural expansion is thought to be jeopardizing the large SOC stock sequestered in its soils. In this paper, we assessed the impact changes in land use have on C sequestration, fractionation and δ13C natural abundance featuring two case studies in the Peruvian Central Puna. We found SOC stocks greater than average temperate grassland soils (between 123 ± 4 and 136 ± 4 Mg C ha− 1 in the 0–30 cm soil profile); however, they did not differ between land uses. In the first case study, depletion of δ13C in mineral associated C in long fallow (> 7 yr) and maca (Lepidium meyenii Walpers) croplands was hypothesized to be caused by disruption of soil aggregates due to tillage and initial greater SOC concentration in maca plots. In addition, SOC loss was found in long fallow plots, and was correlated to steep and low plant cover plots; evidencing that soil degradation does not occur during cropping activity but due to erosion after land abandonment. In the second case study, a long-established perennial ryegrass (Lolium perenne L.) - white clover (Trifolium repens L.) association (> 40 yr) was studied. We did not find an increase in SOC stock under the cultivated pasture. However, we found a better soil aggregation and an increase of 17.3 and 12.2 g C kg− 1WSA in particulate organic C, and SOC within small macroaggregates in cultivated pasture soils. Soil δ13C natural abundance was about 1‰ depleted in all measured C fractions of cultivated pastures when compared to native grasslands, suggesting that pasture-fixed C forms labile and recalcitrant SOC fractions.