Low Vigor Research Articles

Osmopriming, antioxidative action, and thermal stress in sunflower seeds with different vigor levels

The osmopriming technique can reduce the period between sowing and the emergence of seedlings in the field, as well as favor seed performance under stress conditions. This study aimed to evaluate the effect of osmopriming on the physiological performance and antioxidative enzymatic activity of sunflower seeds with different vigor levels and exposed to thermal stress. Three sunflower seed lots of the cultivar Hélio 250 were used. Initially, the seeds were evaluated by germination and vigor tests to characterize the lots. Subsequently, they were primed in a polyethylene glycol 6000 solution at -2.0 MPa and 15 °C for 8 h. Then, the primed and unprimed seeds were tested for physiological quality (germination, first germination count, percentage and emergence speed index of seedlings, and seedling dry matter) and determination of the activity of the enzymes superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POX) under three temperatures: 15 °C (sub-optimal), 25 °C (optimal), and 35 °C (supra-optimal). The physiological tests allowed classifying lots 1, 2, and 3 into three different vigor levels, i.e., high, medium, and low, respectively. Osmopriming favored the performance of sunflower seeds in terms of germination and vigor at all the analyzed temperatures. This effect was more pronounced in lots of lower physiological quality at sub-optimal and supra-optimal temperatures. Sub-and supra-optimal temperatures led to a reduction in the physiological performance of seeds, mainly in less vigorous lots. In general, osmopriming favored an increase in the activity of the enzymes SOD, CAT, POX, and APX, mainly in low vigor seeds exposed to sub and supra-optimal temperatures. Osmopriming of sunflower seeds in PEG 6000 at -2.0 MPa for 8 hours is efficient to improve the performance of less vigorous lots under stress due to the sub- and supra-optimal temperatures, favoring an increase in the activity of enzymes of the antioxidative system.

Toona sureni (blume) merr. Seeds invigoration using 60Co Gamma-Rays irradiation

Deteriorated seeds can be improved by invigoration treatment, including gamma-ray irradiation by Cobalt-60 (60Co). The purpose of this study was to determine the proper dose of gamma-ray irradiation (60Co) to increase the decreased vigor of suren (Toona sureni (Blume) Merr.) seeds. This study uses a factorial completely randomized design (CRD) with aging and irradiation as the treatments. Aging factors consisted of 0, 2, and 4 days. Irradiation factor consisted of 7 levels, namely 0, 5, 10, 20, 40, 80, and 100 Gy, repeated four times. The parameters observed were the electrical conductivity, germination percentage, germination speed, and seedling height. The results showed that Seed aging treatment significantly affected Suren seed germination with 75% (2 days aging) and 56% (4 days aging) germination. The 40 Gy dose of gamma-ray irradiation could increase germination percentage and germination speed of low suren seed vigor increasing 51.42% and 60.21%, respectively. Simultaneously, the cell membrane damage of stored suren increased with gamma-ray irradiation treatment of more than 40 Gy based on electrical conductivity. In seeds with high germination, such as seeds without aging and seed aging for two days with a germination percentage of 80% and 75%, respectively, the invigoration treatment was not effective. Invigoration treatment was effective in increasing the deteriorated or low viability and vigor of the suren seeds.

Magnetic Field Treatments Improves Sunflower Yield by Inducing Physiological and Biochemical Modulations in Seeds.

Magnetic seed enhancement has been practicing as a promising tool to improve germination and seedling growth of low vigor seeds stored under suboptimal conditions, but there is still ambiguity regarding the prospects for magnetism in oilseeds. Present study elucidates the potential of magnetic seed stimulation to improve sunflower germination, growth and yield. Germination and emergence tests were performed to optimize the strength of the magnetic field to sunflower seed enhancement. The seeds were directly exposed to magnetic field strengths of 50, 100 and 150 millitesla (mT) for 5, 10 and 15 min (min) and then standard germination tests were performed. Secondly, the emergence potential of untreated seeds was compared with seed exposed to hydropriming, priming with 3% moringa leaf extract (MLE), priming with magnetically treated water (MTW) for 10 min and priming with 3% MLE solution prepared in magnetically treated water (MTW + MLE). Germination, emergence, seedling growth and seed biochemical properties were used to select the best treatment for field evaluation. The results of the study revealed that magnetic seed treatment with 100 mT for 10 min and seed priming with 3% MLE solution in magnetically treated water (MTW + MLE) significantly improved emergence, crop growth rate and sunflower yield.

Evaluación de calidad de suelos plataneros a través de la actividad microbiana en el sur del lago de Maracaibo, estado de Zulia, Venezuela

The microbial activity can serve as an indicator of the general state of the soil, since it is the reflection of optimal physical and chemical conditions for the development of the metabolic processes of microorganisms that act on the soil, which is why it constitutes an indicator of the dynamics and resource health. With the objective to evaluate the soil quality through microbial activity in banana plantations at the south of Lake Maracaibo, a study was carried out in different production units located in the municipality of Colón of the Zulia state. Lots of banana plants of high and low vigor (AV and BV), for this purpose composite samples the soil at 0-20 cm depth were taken. It was determined: microbial carbon, soil basal respiration, and microbial and metabolic quotient. The results showed that vigor parameters: number of hands per bunch; pseudostem circumference and height of the succession child were significantly higher in VA than in BV, while for microbial carbon, basal soil respiration, and microbial and metabolic ratios, no statistically significant differences were found between vigor lots. The high microbial activity was closely related to the soil texture and, in turn, this positively influenced the biometric parameters of the plants.

Groundwater extraction reduces tree vitality, growth and xylem hydraulic capacity in Quercus robur during and after drought events

Climate change is expected to pose major direct and indirect threats to groundwater-dependent forest ecosystems. Forests that concurrently experience increased rates of water extraction may face unprecedented exposure to droughts. Here, we examined differences in stem growth and xylem hydraulic architecture of 216 oak trees from sites with contrasting groundwater availability, including sites where groundwater extraction has led to reduced water availability for trees over several decades. We expected reduced growth and xylem hydraulic capacity for trees at groundwater extraction sites both under normal and unfavourable growing conditions. Compared to sites without extraction, trees at sites with groundwater extraction showed reduced growth and hydraulic conductivity both during periods of moderate and extremely low soil water availability. Trees of low vigour, which were more frequent at sites with groundwater extraction, were not able to recover growth and hydraulic capacity following drought, pointing to prolonged drought effects. Long-term water deficit resulting in reduced CO2 assimilation and hydraulic capacity after drought are very likely responsible for observed reductions in tree vitality at extraction sites. Our results demonstrate that groundwater access maintains tree function and resilience to drought and is therefore important for tree health in the context of climate change.

Is Precision Viticulture Beneficial for the High-Yielding Lambrusco (Vitis Vinifera L.) Grapevine District?

The best Lambrusco wines are often obtained by blending a representative of the Lambrusco family (i.e. Lambrusco Salamino) with a smaller fraction of Ancellotta, a teinturier variety possessing an extraordinary quality of accumulating color. Due to the economic importance of the Lambrusco business and the rising interest in precision viticulture, a two-year trial was carried out in seven vineyard plots growing both the named varieties. A RapidEye satellite image taken on 9 August 2018, led to vigor maps based on unfiltered normalized difference vegetation index (NDVI). In both the years, ground truthing was performed on the test vines chosen within each vigor area for soil features, vegetative growth, yield, grape, and final wine composition. For data pooled over sites and years, Ancellotta showed a very clear response to NDVA-based vigor mapping as low vigor areas always achieved improved ripening in terms of higher total soluble solids (+1.24 Brix), color and phenols (+0.36 mg/kg and + 0.44mg/kg, respectively), and lower malate (-1.79 g/L) vs high vigor. Such a behavior was shown even in those cases where NDVI of different vigor levels and pruning weight were not closely correlated and, most notably, low vigor matched with a slightly higher yield as compared to high vigor plots. Overall, the high yielding Lambrusco Salamino was less responsive in terms of vine performance and grape composition versus intra-vineyard variability. This study highlights that, in Ancellotta, adjusting the vine balance toward ostensible lower vigor (i.e pruning weight ≤ 1 kg/m) would result in a superior choice in terms of improved ripening and wine profiles would not be detrimentally impacted by the yield level which, in fact, increased in some cases.

Correlation between vigor by accelerated aging at pre-sowing and soybean seedling emergence in the field

Although the accelerated aging test is widely used to determine seed vigor, there are methodological variations in seed exposure time at 41 °C. Therefore, the objective was to indicate the most appropriate seed exposure time to segregate lots that also exhibits a correlation with seedling emergence in the field, and establish vigor levels using the aforementioned test. Soybean seed samples were collected at pre-sowing, representing 100 lots in the 2016/2017 growing season and 125 lots in the 2017/2018 season from different warehouses in 4 regions of Santa Catarina state (SC). Physiological quality was evaluated by germination, accelerated aging (24 and 48 h at 41 °C) and field emergence tests. The results were submitted to descriptive statistical analysis and Pearson’s correlation analysis (p < 0.05). The rank sum index, associated with the Scott-Knott clustering method, was used to classify physiological quality. The average germination percentage was 90 and 91% in the 2016/2017 and 2017/2018 growing seasons, respectively. Vigor obtained an average of 86 (2016/2017) and 85% (2017/2018), when seeds were submitted to accelerated aging for 48 h, and 89% (both seasons) for 24 h. In regard to field emergence, the average was 85 and 80% in the 2016/2017 and 2017/2018 growing seasons, respectively. Considering the 225 lots, the greatest correlation with field emergence was observed in vigor - 48 h (r = 0.71 p < 0.05). Rank sum classification made it possible to establish vigor-based categories, whereby batches with over 85% vigor by 48-h accelerated aging were classified as high vigor, 70 to 84% medium vigor, and under 70% low vigor.

Plant resilience and physiological modifications induced by curettage of Esca-diseased grapevines

The re-emergence of Grapevine Trunk Diseases (GTDs), mainly Esca, has been observed in most of the world’s vineyards during the last two decades. Development of necrosis in grapevine wood, especially white-rot, is typically associated with Esca-diseased plants. One of the different methods being used in attempts to eradicate GTDs is curettage. This old cultural practice, which consists in surgically removing the necrotic wood, specifically white-rot, retaining only the non-necrotic tissue of Esca-diseased grapevine, is used in some European vineyards (Spain, France, Italy, Portugal), and is being increasingly reintroduced since 10 years ago in France. We, therefore, wanted to study the effect of curettage on vigour, fertility and berry quality, and year after year plant recovery. Our study synthetizes a 3-year experiment on Esca-diseased cv. Sauvignon blanc grapevines curetted in a commercial plot in the Bordeaux region. Asymptomatic control grapevines were compared to Esca-diseased grapevines without curettage (with typical foliar symptoms), and with curetted Esca-diseased grapevines (without foliar symptoms). Even if the curetted grapevines recovered lower vigour and fertility than the control plants, their grape berry quality was comparable, unlike for Esca-diseased grapevines. This cultural practice proved particularly effective in helping Esca-symptomatic grapevines to recover asymptomatic after treatment. Over time, curettage induces the resilience of grapevines, allowing them to recuperate their full physiological functioning, thereby compensating for Esca’s detrimental impact on berry quality.

Effects of declining oak vitality on ecosystem multifunctionality: Lessons from a Spanish oak woodland

Mediterranean oak woodlands are currently facing unprecedented degradation threats from oak decline. The Iberian oak decline “Seca”, related to Phytophthora infection, causes crown defoliation that may adversely affect ecosystem services (ESs). We aim to improve our understanding of how Seca-induced declines in crown foliation affect the provision of multiple ecosystem services from understory vegetation. We selected holm (Quercus ilex) and cork oak (Q. suber) trees in a Spanish oak woodland and evaluated three proxies of canopy effects. One proxy (crown defoliation) solely captured Seca-dependent effects, one proxy solely captured Seca-independent effects (tree dimensions such as diameter and height), while the third proxy (tree vigor) captured overall canopy effects. We then used the best-performing proxies to assess canopy effects on key ecosystem services (ESs) such as above-ground net primary production (ANPP), grass and legume biomass, species diversity, litter decomposition rates, and a combined index of ecosystem multifunctionality.We found that both types of canopy effects (i.e. Seca-dependent and Seca-independent effects) were related, indicating that ANPP was disproportionally more affected by Seca when defoliated trees were large. Responses of other ESs were mostly not significant, although lower species diversity was found under trees with intermediate vigor. Our results underline that a Seca-related decline in canopy density triggered a homogenization of ecosystem service delivery on the ecosystem scale. The ecosystem functions (EFs) under trees of low vigor are similar to that in adjacent open microsites indicating that the presence of vigorous (i.e. old and vital) trees is critical for maintaining EFs at a landscape level. Our results also highlight the importance of quantifying not only defoliation but also tree dimensions as both factors jointly and interactively modify canopy effects on ecosystem multifunctionality.

Impact of accelerated aging process on seed quality and biochemical changes of Dendrocalamus sikkimensis Gamble

Dendrocalamus sikkimensis Gamble is a large-sized sympodial bamboo species with clustering culms and few culms. Although, profuse seeding occurred in this species during mast flowering, seed viability was very low under ambient storage conditions. Present investigation focuses on the changes in seed viability and seedling growth during accelerated ageing and associated changes in biochemistry of seeds. The seed incubation was at 42 ± 1 °C and 100% relative humidity for 0, 1, 3, 5 and 8 days. Initial germination of 51.49% in the fresh seeds declined to 11.7% after 8 days of accelerated ageing, which indicated that the seeds are of low vigour and will lose viability rapidly under natural conditions. Biochemical analysis indicated a decrease in sugar, starch and protein, starch content with the progression of accelerated ageing. The sudden decline of seed viability and germination during seed ageing can be due to biochemical changes. There was decline in the acid and alkaline phosphatase and peroxidase activity and increase in α and β-amylase activity with seed ageing. Therefore, the reduction in seed viability of D. Sikkimensis seeds can be due to changes in the biochemical characteristics and function of enzymes involved in seed reserve food depletion. The quantification of seed fat and fatty acid methyl esters also supported the same.

Nitrate Uptake and Transport Properties of Two Grapevine Rootstocks With Varying Vigor.

In viticulture, rootstocks are essential to cope with edaphic constraints. They can also be used to modulate scion growth and development to help improve berry yield and quality. The rootstock contribution to scion growth is not fully understood. Since nitrogen (N) is a significant driver of grapevine growth, rootstock properties associated with N uptake and transport may play a key role in the growth potential of grafted grapevines. We evaluated N uptake and transport in a potted system using two grapevines rootstocks [Riparia Gloire (RG) and 1103 Paulsen (1103P)] grafted to Pinot noir (Pommard clone) scion. Combining results of nitrate induction and steady-state experiments at two N availability levels, we observed different responses in the uptake and utilization of N between the two rootstocks. The low vigor rootstock (RG) exhibited greater nitrate uptake capacity and nitrate assimilation in roots after nitrate resupply than the more vigorous 1103P rootstock. This behavior may be attributed to a greater root carbohydrate status observed in RG for both experiments. However, 1103P demonstrated a higher N translocation rate to shoots regardless of N availability. These distinct rootstock behaviors resulted in significant differences in biomass allocation between roots and shoots under N-limited conditions, although the overall vine biomass was not different. Under sufficient N supply, differences between rootstocks decreased but 1103P stored more N in roots, which may benefit growth in subsequent growing seasons. Overall, greater transpiration of vines grafted to 1103P rootstock causing higher N translocation to shoots could partially explain its known growth-promoting effect to scions under low and high N availability, whereas the low vigor typically conferred to scions by RG may result from the combination of lower N translocation to shoots and a greater allocation of biomass toward roots when N is low.

Effect of seed coating polymers on performance in soybean (Glycine max. L) Var. JS335

Seed coating especially film coating, is one such technique which has gained commercial importance owning to its practical utility as an effective delivery system as seed protectant and fortifying chemicals which maintain good germinability and vigour in field as well as laboratory viz.,strong seedlings grow faster than less vigorous ones, are more tolerant to adverse conditions in the seedbed and are better to resist diseases. Seeds of soybean cv. JS-335 were coated with polymer ((DISCO AG SP RED L-200), protectant (thiram and carboxin), bioagent (Mycorrhiza) and polymer untreated seeds as control. It was observed that, irrespective of the treatments, the seed quality parameters declined progressively with the increase in storage period (12 months). Under field conditions, higher vigour (2348) was noticed in seed treated with polymer (DISCO AG SP RED L-200) + Thiram + Quick roots **/ Mycorrhiza and lower vigour was seen inno polymer treatment or water + thiram. The field emergence (%) revealed that all the three polymer seed coating treatments were on par at 30 DAS (78.07 %, 77.19 % and 77.19 %) and 50 DAS (80.99 %, 80.11 % and 79.56 %) when compared to control treatment i.e., no polymer treatment or water + thiram at 30 DAS (71.68 %) and 50 DAS (71.30 %), respectively. Among the yield attributes, significant difference was observed in seed yield/plant with treatment polymer (DISCO AG SP RED L-200) + Thiram + Quick roots **/ mycorrhiza registering highest (22.20 g) yield, while the lowest (18.40 g) yield was observed in polymer untreated or water + thiram.

Growth and dry matter partition wheat plants in response to seed vigor and water restriction

Abstract: The quality of the seeds and the occurrence of stresses are decisive for the development of the crops. Thus, the work aimed to verify the effect of seed vigor on growth and dry weight partition of wheat plants subjected to water stress. For growth evaluation, the experimental design was completely randomized, in a 2 x 2 x 8 factorial scheme (vigor level x water regime x collection time), with four replications. To evaluate the yield of the seeds, the design was completely randomized, in a 2 x 2 factorial scheme (level of vigor x water regime), with four replications. Total dry weight, dry weight production rate, relative growth rate, leaf area ratio, leaf area, solar energy conversion efficiency, dry weight partition and harvest index were evaluated. Total dry weight production, dry weight production rate, leaf area, leaf weight ratio, solar energy conversion efficiency and yield were higher for plants from highly vigorous seeds under field capacity. The yield was higher for plants with high vigor compared to those with low vigor in field capacity.

Effect of seed vigor and sowing densities on the yield and physiological potential of wheat seeds

Abstract: Initial seed vigor and sowing density interact in establishment of plants in the field, and can thus affect expression of the plasticity of the wheat crop and the yield and physiological quality of the seeds produced. The aim of this study was to evaluate the effect of seed vigor levels in combination with sowing densities on the yield and physiological potential of wheat seeds. The cultivars BRS Gralha-Azul and BRS Sabiá were used in a randomized block experimental design in a 2 × 4 factorial arrangement, with four replications. The treatments consisted of seeds of high and low vigor and four sowing densities (150, 250, 350, and 450 seeds.m-2). The following evaluations were made: seed yield, germination, first germination count, seedling length, seedling dry matter, accelerated aging, emergence speed index, and seedling emergence in sand. An increase in sowing density favors the seed yield of both cultivars; however, it reduces the vigor of the seeds produced by the cultivar BRS Gralha-Azul, especially of the seeds produced by plants originating from high vigor seeds. For the cultivar BRS Sabiá, an increase in sowing density decreases the germination performance of seeds produced by plants originating from low vigor seeds.

Poblaciones de fitonematodos asociados al vigor de plantas de plátano

Introducción. La fracción biótica del suelo es el componente esencial en los procesos ecológicos y pueden ejercer influencia en la productividad agrícola de los cultivos. Objetivo. Identificar la población de fitonematodos asociados al vigor de las plantas de plátano en la zona de sur del lago de Maracaibo, Venezuela. Materiales y métodos. Se seleccionaron ocho lotes de plantas de plátano (Musa AAB cv. Hartón) de 2 ha, ubicados en el sur del lago de Maracaibo, los cuales se dividieron en dos áreas o lotes de 1 ha, durante octubre y diciembre del año 2018. La designación de los lotes por vigor (AV= alto vigor y BV= bajo vigor) se realizó con base en los parámetros del número de manos por racimo, circunferencia de la planta madre y altura del hijo de sucesión, en veinte plantas próximas a la cosecha, por cada uno. La muestra de suelo se recolectó a 15 cm de profundidad en tres plantas recién florecidas por lote y para las raíces se realizó una microcalicata por planta hasta 30 cm de profundidad. Para la extracción nematológica en suelo se empleó el método de levigación de oostenbrink con embudo de Baermann y en raíz el método de licuado. Posteriormente, se cuantificó por género los especímenes encontrados. Resultados. Se encontró una población en el suelo (14 140 individuos) más significativa (p<0,05) que en la raíz (2670 individuos). Al comparar la población total por vigor no se observó diferencia estadística entre AV (395) y BV (305). Se determinaron doce géneros taxonómicos en las muestras de raíz y en suelo. Los especímenes más predominantes en AV fueron Helicotylenchus multicinctus y Radopholus similis y en los lotes BV fue Pratylenchus sp. Conclusión. Se observó una alta diversidad de la nematofauna presente tanto en los suelos como en raíces del cultivo.

Формування врожайності інтенсивних насаджень черешні (Cerasus avium L.) залежно від довжини інтеркаляра ВСЛ 2 в зоні Південного Степу України

The comparative evaluation of the predicted (biological) and actual yields of the sweet cherry Valerii Chkalov and Melitopolska Chorna, grafted on the interstem VSL 2 (the main rootstock is Mahaleb seedlings) was carried out in the intense orchards under the conditions of the Southern Steppe of Ukraine. The trees with the interstem VSL 2 length 30 cm appeared to be characterized by the highest spur density, displaying an increase by 19 and 11 %, as compared to tress with the interstem length 20 cm (control) and 50 cm respectively. Cv Melitopolska Chorna on the 2-4-year-old wood had the 1.3-1.6 times higher spur density than ‘Valerii Chkalov’. The analysis of the total number of spurs per tree showed that for VSL 2 length 20 and 30 cm, this index was, on the average, 1233 and 1252 pcs./tree respectively. Only when the interstem length increased to 50 cm, there was a decrease in the number of spurs per tree by 23 %. That can be explained by the reduction in vigour of the trees in this variant. The studied varieties proved to react to the change of VSL 2 length in different ways: the average yield of the ‘Valerii Chkalov’ – trees in 2014-2018 in the variants with the interstem length 20 cm (control) was equal to that with the length 30 cm – 8.9 and 9.0 t/ha respectively, but than lower with length of 50 cm – 8.6 t/ha. The trees of ‘Melitopolska Chorna’ with the interstem length 30 cm showed the highest yield – 10.1 t/ha. That surpassed the control variant by 26 %. The decrease of the yield in the variant the VSL 2 length 50 cm on the both studied strains can be explained by the lower vigour causing fewer amount of the spurs formed on a tree. In the conditions of the Southern Steppe of Ukraine the intense sweet cherry orchards during the years with the favourable weather conditions, turned out to be able to apply their productivity potential by 69-78 %.

Moisture Dependent Selected Engineering Properties of Deenanath Seeds in Relation to Development of Processing Machinery

Propagation of grasses through seeds is important in view of vigour and germination. Various grasses as Pennisetum pedicellatum Trin., Cenchrus ciliaris L., Chrysopogan fulvus have lower vigour and germination, due to which they need specific operations as defluffing, separation of true seeds, cleaning and grading by specific machines. In designing a machine for a specific use, physical properties and their behaviour with moisture play an important role. A study was conducted to assess the effect of moisture content at five levels [6.88 - 19.23 %, (d.b.)] on selected physical properties of defluffed Deenanath grass seed. The length, width, thickness, arithmetic mean diameter, and geometric mean diameter of defluffed Deenanath seed increased from 2.30 mm to 2.56 mm, 0.71 mm to 0.96 mm, 0.47 mm to 0.63 mm, 1.16 mm to 1.38 mm, and 0.90 mm to 1.15 mm, respectively, with increase in moisture content 6.88 % to 19.23 %. Bulk density, true density, and porosity decreased from 652.16 kg.m-3 to 585.78 kg.m-3, 852.63 kg.m-3 to 792.71 kg.m-3, and 25.62 % to 24.97 %, respectively, with increase in moisture content from 6.88 % to 19.23 per cent. The aspect ratio, sphericity, surface area, volume, and thousand-seed mass of the seed were in the range of 30.91 - 37.51 %, 0.39 - 0.45, 2.58 - 3.23 mm2, 3.71 - 4.97 mm3, and 0.480 - 0.523 g, respectively. Linear relationships with correlation coefficients higher than 0.90 were observed for the physical properties over the experimental range of moisture content.

Single count of radicle emergence, DNA replication during seed germination and vigour in alfalfa seed lots

Previous work on alfalfa seeds has illustrated the close association between the rate of germination and vigour. This study examined single early counts of radicle emergence (RE) as an indirect method to measure the rate of germination in alfalfa, and investigated cell cycle activities in the early stages of imbibition. The 6-hour interval counts of just germination (JG) and germination percentages (G) of 14 seed lots at 20, 17, 15 and 13°C were compared with final emergence and mean emergence time. Single counts of JG and G were strongly correlated with mean just germination time (MJGT), mean germination time (MGT) (P < 0.01) and field performance. The results indicate that single counts of RE after 24 hours at 20°C could be used to predic the vigour of alfalfa seeds. The embryo root tip cells of six seed lots with low, medium and high vigour were used for analysis of DNA replication by flow cytometry 3, 6, 12, 18 and 24 hours after imbibition. The 4C/2C ratio 18 hours after imbibition and the increase in 4C/2C ratio between 6 and 12 hours after imbibition was associated with the vigour of the seed lot and has the potential to predict seed vigour.

Rootstock Genotypes Shape the Response of cv. Pinot gris to Water Deficit

Understanding the physiological basis underlying the water stress responses in grapevine is becoming increasingly topical owing to the challenges that climate change will impose to grapevine agriculture. Here we used cv. Pinot gris (clone H1), grafted on a series of tolerant (1103Paulsen; P), sensitive (SO4) and recently selected (Georgikon28; G28, Georgikon121; G121, Zamor17; Z17) rootstocks. Plants were either subjected to reduced water availability (WS) or maintained at pot capacity (WW). Photosynthetic (light response curves), stomatal and in vivo gas exchange analysis were carried out as well as dynamics of daily water use (WU), leaf area accumulation with affordable RGB imaging pipelines and leaf water potential. Significant genotypic variation was recorded between rootstocks for most of the traits analyzed under optimal conditions with P and SO4 showing a more vigorous growth, higher CO2 assimilation rate, stomatal conductance and stomatal density per unit of leaf area than G28, G121, Z17 (p < 0.001). Under WS, rootstocks induced different water stress response in Pinot gris, with G28 and G121 showing a higher sensitivity of water use to reduced water availability (WS) (p = 0.021) and no variation for midday leaf water potential until severe WS. P, Z17 and to some extent SO4 induced a pronounced near-anisohydric response with a general WU maintenance followed by reduction in leaf water potential even at high levels of soil water content. In addition, G28 and G121 showed a less marked slope in the linear relationship between daily water use and VPD (p = 0.008) suggesting elevated sensitivity of transpiration to evaporative demand. This led to an insensitivity for total dry weight biomass of G28 and G121 under WS conditions (p < 0.001). This work provides: (i) an in-depth analysis for a series of preferable traits under WS in Pinot gris; (ii) a characterization of Pinot gris × rootstock interaction and a series of desirable traits under WS induced by several rootstocks; (iii) the potential benefit for the use a series of affordable methods (e.g., RGB imaging) to easily detect dynamic changes in biomass in grapevine and quickly phenotype genotypes with superior responses under WS. In conclusion, the near-isohydric and conservative behavior observed for G28 and G121 coupled with their low vigor suggest them as potential Pinot gris rootstock candidates for sustaining grapevine productivity in shallow soils likely to develop terminal stress conditions.

EVALUATION OF SWEET CHERRY CULTIVARS UNDER THE CONDITIONS FROM THE SILVOSTEPPE AREA IN MOLDOVA

The promotion of a cherry assortment with constant yield, low vigour of the trees, self-fertility and high productivity, resistance to biotic and abiotic factors and with ripening at the extremities of the cherries maturation season, represents a permanent concern of researchers. In this context, considering the current patrimonial situation and the perspectives of growing sweet cherry trees in the Iasi area, under a privatized agriculture, the selection of new cultivars to be introduced in the assortment requires a special attention. Analyzing the values of the fertility index during the three years of study (2018 – 2020) it was observed that all the cherry cultivars excepting ‘Kordia’ are highly fertility with values between 30.0% and 66.2%. The cultivars ‘Bucium’, ‘Croma’, ‘Van’, ‘Maria’, ‘Stella’, ‘Cătălina’, ‘Margonia’ and ‘George’ have large fruits (over 7 g and over 22.5 mm) and ‘Kordia’ (6.3 g and 21.1 mm), ‘Scorospelka’ (6.2 g and 22.3 mm), ‘Cetăţuia’ (6.0 g and 22.0 mm) and ‘Rivan’ (5.9 g and 21.6 mm) have small fruits. For ‘Scorospelka’, ‘Cetăţuia’ and ‘Rivan’, the fruits are large in comparison with other early cultivars. The values of soluble dry substance (SDS) varied between 13.6% (‘Scorospelka’ and ‘Rivan’) and 18.9% (‘Maria’). However, statistically, cultivars ‘Maria’ (18.9%), ‘Bucium’ (18.3%) and ‘George’ (18.1%) recorded superior values in comparison with all the other cultivars.