Post-flowering Period Research Articles

Maize Responses to High Night Temperature During Postflowering and Early Grain Filling: Effects on Yield Components, Kernel Growth and Dry Matter Allocation

ABSTRACTWarm night frequency has increased steadily in the last years across maize production regions, but high night temperature (HNT) effects on growth, grain yield and maize dry matter allocation (DMA) to different plant organs remain poorly understood. In this study, we aimed to (i) analyse the DMA among reproductive and vegetative organs, (ii) evaluate the individual kernel weight through its determinants, rate and duration of grain filling and (iii) quantify changes in grain yield per plant and its components due to HNT during the postflowering and early grain‐filling period. Field‐grown maize was subjected to HNT induced by shelters during a 15‐ or 30‐day period after silking, encompassing the postflowering period (HNT15) and extending the heating into early grain filling (HNT30), respectively. The HNT was applied from 1900 to 0700 h while control plots remained at ambient night temperature (ANT). Kernel number per plant was decreased under both temperature regimes (i.e., HNT15 and HNT30); however, significant reductions in grain yield were only observed under HNT30. The DMA during the heating period was differentially affected by the duration of heating. While DMA to the stem was likewise reduced by both heating treatments, the partition to the uppermost ear was only reduced under HNT30. Related to the lack of response to HNT treatments of the rate and duration of grain filling, the individual kernel weight was not reduced. The source‐sink ratio was not affected by HNT, meanwhile, the apparent reserve use was significantly reduced under HNT30. Our results demonstrate that the magnitude of HNT effects is subjected to the duration of the heating period, but also depends on the intensity of heating explored across seasons, especially for kernel number and grain yield.

Effects of Deep Vertical Rotary Tillage on Soil Water Use and Yield Formation of Forage Maize on Semiarid Land

Forage maize is one of the most important feed crops for livestock production, and is mainly grown in northwest China. However, their growth is often stressed by limited soil water availability due to the arid climate. To provide more soil moisture, a high-efficiency tillage technique was required to make crops effectively use soil moisture in deep soil layers. Deep vertical rotary tillage is a promising choice for this purpose. In this study, a long-term (2020–2022) field experiment consisting of three treatments, i.e., traditional tillage (TT), deep rotary tillage (DT), and deep vertical rotary tillage (VRT), was carried out in semiarid areas of Loess Plateau, northwest China, to investigate the effects of VRT on soil water storage (SWS), phase crop evapotranspiration (ETc) during the pre- and post-flowering periods, dry matter accumulation, grain yields and the water use efficiency (WUE) of forage maize. The results showed that VRT significantly improved the absorption of soil moisture from deep layers, especially in dry years. During the pre-flowering period of a dry year (2020), VRT decreased SWS by 7.6%–10.0% in the 60–180 cm layer, and by 17.6%–18.5% in the 180–300 cm layer, respectively, compared to DT and TT. As a result, VRT increased ETc during the pre-flowering period by 6.1% and 9.2%, respectively. In wet years (2021 and 2022), VRT increased total ETc by 2.0%–7.9% in 2021, and by 10.1%–14.9% in 2022, respectively. On average, VRT increased the dry matter weight per plant by 1.0%–7.8%, grain yields by 2.4%–38.6%, biomass yields by 3.4%–16.2%, and WUE by 10.1%–30.0%, respectively. Particularly, the benefit of VRT for increasing yields and WUE was more noticeable in dry years. It can be concluded that VRT is a drought-tolerant and yield-boosting tillage technique that is suitable for rain-fed forage maize in semiarid areas of Loess Plateau, northwest China.

Nitrogen deficiency in maize fields of the Southern Pampas does not affect kernel number but reduces weight per kernel.

Nitrogen (N) requirement of maize has been increasing over the past decades, but there has been a lack of adjustment in fertilization management practices across different regions in Argentina. The higher N requirement in modern hybrids is associated with a higher post-flowering N accumulation. Additionally, soil fertility in the Argentina Pampas has consistently decreased in recent years. Whether the effects of N deficiency are expressed in the post-flowering period is still unclear at field level. The objective of this work was to quantify the yield reduction attributed to N deficiency and to identify the physiological basis of this effect at the field level for typical high-tech farms across the south-eastern Pampas of Argentina. Nineteen experiments were conducted during the 2020/2021 growing season in the south-eastern Pampas, evaluating two N managements i) Farmers' N level; ii) High N input. Results showed that the additional N input increased grain yield by an average of 6.4% (average grain yield difference of 712 kg ha−1). Weight per kernel was the only yield component that responded to N fertilization. Farmers' N management did not affect N accumulation or growth-related variables such as leaf area index, green leaves per plant, PAR interception, nitrogen sufficiency index until flowering, but the farmers' N level reduced these variables during the grain filling period leading to differences in aerial biomass and N accumulated at physiological maturity. Farmers' N level led to decreased post-flowering N uptake during grain filling period, which reduced the photosynthetic capacity of the canopy. These findings suggest that N management strategies and models need to be reviewed for high-tech maize systems.

Yield and quality traits of wheat and rapeseed in response to source-sink ratio and heat stress in post-flowering

The probability of occurrence of high temperatures and cloudiness events increases during the post-flowering period of temperate crops in the southern cone of South America. Several studies have evaluated the effect of high temperature or shading on wheat and rapeseed, but little is known about the impact of the combined effect of both stresses on the yield and grain quality of these crops during the post-flowering phase. This study aims to analyze the sensitivity and stability of wheat and rapeseed grain yield and quality in response to shading, high temperature and the combined stresses during post-flowering in two contrasting environments. Field experiments were carried out using the same wheat and rapeseed genotypes in environments with high (Valdivia, Chile) and medium (Buenos Aires, Argentina) yield potential. The treatments consisted of i) control, ii) shading stress, iii) heat stress and iv) combined shading and heat stress during the central hours of day. Portable chambers were placed on the plots at 7–10 days from anthesis in wheat and 14 days from the beginning of flowering in rapeseed, throughout 10 days. Grain yield was significantly reduced for the combined stress in wheat (−46%) and rapeseed (−39%) in Buenos Aires, but there were no differences between treatments in any crop in Valdivia. Combined stress in rapeseed produced a trade-off between grain number (−40%) and grain thousand weight (+43%) in Valdivia, while grain thousand weight was penalized (−25%) in Buenos Aires. For wheat there were no differences in grain protein in both locations, while for rapeseed protein increased due to the combined stress in Buenos Aires (+15%), no effects were recorded for grain oil in either location. Our results showed a high stability of grain weight in rapeseed to single and combined environmental stresses, with better environmental conditions during grain filling.

Weather conditions affect pollinator activity, fruit set rate, and yield in Japanese apricot

Japanese apricot blooms in mid-winter, and thus severe weather conditions, including low temperatures, sometimes limit pollinator activity and consequently decrease fruit set rate and yield. Plant physiology is also affected by weather conditions. In this study, we aimed to evaluate the effect of pollinator activity on fruit set rate and yield, in comparison with the effects of meteorological factors. First, we conducted field experiments in 2021 and 2022 at Wakayama prefecture. The results showed that honey bee visitation increased as ambient temperature increased. Fruit set rate also increased under warm conditions when Japanese apricot was naturally pollinated by honey bees. In contrast, hand-pollinated flowers were not affected by ambient temperature. These results revealed that low temperature during the flowering period decreased pollinator visitation but did not affect plant fertilization ability. To compare pollinator activity with meteorological factors over a long period, including the pre- and post-flowering periods, we used a state-space model describing the time series of fruit set rate. The model using fruit set rate data and meteorological records over 15 years (2007–2021) at the Japanese Apricot Laboratory showed that the pre-blossom temperature and number of days suitable for pollination significantly affected the fruit set rate. Another model for the time series of fruit yield using the fruit yield records over 46 years (1976–2021) in Wakayama prefecture showed that fruit yield was affected by number of suitable pollination days, pre-blossom temperature, and sunshine duration before harvest. Moreover, the introduction of Western honey bees into orchards had considerable effects on fruit yield. These results indicate that pollinator activity (which is responsive to weather conditions) and pre-blossom temperature have a significant influence on fruit set rate and yield in Japanese apricot.

Variation of yield and physiological characteristics of Lathyrus sativus L. populations under terminal drought

Grass pea is one of the oldest native crops grown in vast geographical regions of Iran, however ‎little is known about its tolerance to water shortage during post flowering period. We conducted ‎field experiments in 2018 and 2019 to study the effects of terminal drought on growth, yield, and ‎some physiological characteristics of grass pea (Lathyrus sativus L.) ecotypes. Nine local grass pea ‎ecotypes (Baft_1, Baft_2, Bardsir, Dehbakri, Kuhbanan, Rabor, Sirjan, Shiraz, and Torbat ‎Heydarieh), collected from different climatic regions in the east, southeast, and south of Iran, were ‎exposed to either normal irrigation or terminal drought (water withholding after flowering). Normal ‎irrigation was applied after 60 mm water evaporation from class A evaporation pan for the whole ‎growing season. Terminal drought decreased seed and biological yields, relative to normal ‎irrigation, with Baft_2 and Rabor the superior ecotypes in both treatments. Among yield traits, pod number per plant had very high correlation with seed and biological yields in either irrigation regime and was the highest in high yielding ecotypes. Leaf surface area, relative water content (RWC) and starch content decreased while soluble sugars and proline content increased by terminal drought. The highest yielding ecotypes, Baft_2 and Rabor had not the highest leaf area and RWC though they had the highest starch content under normal and sugars content under terminal drought. Also they had the greatest water use efficiency in both years and watering regimes. Proline content, RWC and sugar contents did not significantly correlate with seed or biological yield under terminal drought. Our results suggest that drought tolerance in ‎grass pea is closely associated with better utilization of water and plant photosynthetic capacity, as reflected in high starch ‎accumulation and conversion to sugars, perhaps as an osmotic adjustment factor. Also, high yielding ecotypes allocated higher dry matter to reproductive tissues.

Mapping rapeseed planting areas using an automatic phenology- and pixel-based algorithm (APPA) in Google Earth Engine

The timely and rapid mapping of rapeseed planting areas is desirable for national food security. Most current rapeseed mapping methods depend strongly on images with good observations obtained during the flowering stages. Although vegetation indices have been proposed to identify the rapeseed flowering stage in some areas, automatically mapping rapeseed planting areas in large regions is still challenging. We developed an automatic phenology- and pixel-based algorithm (APPA) by integrating Landsat 8 and Sentinel-1 satellite data. We found that the Normalized Rapeseed Flowering Index shows unique spectral characteristics during the flowering and post-flowering periods, which distinguish rapeseed parcels from other land-use types (urban, water, forest, grass, maize, wheat, barley, and soybean). To verify the robustness of APPA, we applied APPA to seven areas in five rapeseed-producing countries with flowering images unavailable. The rapeseed maps by APPA showed consistently high accuracies with producer accuracies of (0.87–0.93 and F-scores of 0.92–0.95 based on 4503 verification samples. They showed high spatial consistency at the pixel level with the land cover Scientific Expertise Centres (SEC) map in France, Crop Map of England in United Kingdom, national-scale crop- and land-cover map of Germany, and Annual Crop Inventory in Canada at the pixel level. We propose APPA as a highly promising method for automatically and efficiently mapping rapeseed areas.

Deciphering Main Climate and Edaphic Components Driving Oat Adaptation to Mediterranean Environments.

Oat, Avena sativa, is an important crop traditionally grown in cool-temperate regions. However, its cultivated area in the Mediterranean rim steadily increased during the last 20 years due to its good adaptation to a wide range of soils. Nevertheless, under Mediterranean cultivation conditions, oats have to face high temperatures and drought episodes that reduce its yield as compared with northern regions. Therefore, oat crop needs to be improved for adaptation to Mediterranean environments. In this work, we investigated the influence of climatic and edaphic variables on a collection of 709 Mediterranean landraces and cultivars growing under Mediterranean conditions. We performed genotype–environment interaction analysis using heritability-adjusted genotype plus genotype–environment biplot analyses to determine the best performing accessions. Further, their local adaptation to different environmental variables and the partial contribution of climate and edaphic factors to the different agronomic traits was determined through canonical correspondence, redundancy analysis, and variation partitioning. Here, we show that northern bred elite cultivars were not among the best performing accessions in Mediterranean environments, with several landraces outyielding these. While all the best performing cultivars had early flowering, this was not the case for all the best performing landraces, which showed different patterns of adaption to Mediterranean agroclimatic conditions. Thus, higher yielding landraces showed adaptation to moderate to low levels of rain during pre- and post-flowering periods and moderate to high temperature and radiation during post-flowering period. This analysis also highlights landraces adapted to more extreme environmental conditions. The study allowed the selection of oat genotypes adapted to different climate and edaphic factors, reducing undesired effect of environmental variables on agronomic traits and highlights the usefulness of variation partitioning for selecting genotypes adapted to specific climate and edaphic conditions.

Microscopic and pharmacognostic standardization of Astragalus scorpiurus Bunge.

The aim of the current study was to assess and compare the microscopic and pharmacognostic features of the selected parts of Astragalus scorpiurus Bunge. It is an annual and prostrate herb. Anatomy of leaves, stem, and root depicted a typical dicot structure. It will provide information regarding standardization and authentication. The powder drug study (Light Microscopy and Scanning Electron Microscopy) revealed the presence of xylem and phloem vessels, epidermal fragments, cortical cells, fibers, parenchyma tissue, calcium oxalate crystals, nonglandular trichomes, anomocytic stomata, and so on. It will be helpful in identification and quality control. Pollen and seeds micro-morphological features were observed through LM and SEM. These will play a vital role in the taxonomical identification of taxa and provide satisfactory information for taxonomists. Fluorescence analysis revealed different colors under visible and UV light. Extractive values were determined. Powder of the plant parts revealed high extraction in methanol followed by ethanol. Elemental and nutritional profiling were evaluated during two phenological periods that is, vegetative and postflowering period. There were significant phenological variations in mineral and nutritional status of the herb. These parameters are crucial for drug prescription and drug designing. These also provided information regarding nutraceutical and therapeutic value of this herb.

The effects of pollinizers on pollen tube growth and fruit set of European plum (Prunus domestica L.) in a Nordic climate

Norwegian plum production is characterized by climatic limitations, different flowering time, deficiently of wholly-adapted cultivars and appropriate pollen donors for cultivars that can be grown in this region. This study evaluated the progamic phase of fertilization and fruit set in four European plum cultivars (´Mallard´, ´Edda´, ´Jubileum´, and ´Reeves´) after crossing with different pollinizers over two years (2018/2019). Reproductive parameters, in vitro pollen germination, number of pollen tubes in the upper part of the style and locule of the ovary, number of pistils with ovule penetrated by pollen tube, fruit set in all crossing combinations, and fruit set in open pollination of pollen recipient cultivars showed different adaptability of both recipient and donor cultivars to the specific ecological conditions prevailing in Western Norway. The pollinizers ´Victoria´, ´Opal´ and ´Č. Lepotica´ proved to be a very good pollinizers for cultivar ´Jubileum´, while pollinizers ´R. C. Souffriau´ and ´Valor´ for the cultivar ´Reeves´. Cultivars ´Opal´, ´R. E. Prolific´ and ´Mallard´ are excellent pollinizers for ´Edda´ in conditions of higher temperatures during flowering period and post-flowering period. Cultivar ´Č. Lepotica´ proved to be the best pollinizer for ´Edda´ in conditions when the temperatures were lower. Cultivars ´Opal´ and ´R. E. Prolific´ can be considered as good pollinizers for ´Mallard´.

Assessment of heat stress and cloudiness probabilities in post-flowering of spring wheat and canola in the Southern Cone of South America

Episodes of heat stress constrain crop production and will be aggravated in the near future according to short and medium-term climate scenarios. Global increase in cloudiness has also been observed, decreasing the incident solar radiation. This work was aimed to quantify the probability of occurrence of heat stress and cloudiness, alone or combined, during the typical post-flowering period of wheat and canola in the Southern Cone of South America. Extended climate series (last 3–5 decades with daily register) of 33 conventional weather stations from Argentina, Brazil, Chile and Uruguay (23 to 40°S) were analysed considering the period from September to December. Two different daily events of heat stress were determined: (i) maximum daily temperature above 30 °C (T > 30 °C) and (ii) 5 °C above the historical average maximum temperature of that day (T + 5 °C). A cloudiness event was defined in our work as incident solar radiation 50% lower than the historical average radiation of that day (R50%). The T > 30 °C event increased its probability of occurrence throughout the post-flowering phase, from September to December. By contrast, the risk of T + 5 °C event decreased slightly, just like for R50%, and the higher the latitude, the lower the probability of R50%. The T > 30 °C plus R50% combined stresses reached greater cumulated probabilities during post-flowering, compared to T + 5 °C plus R50%, being 42% vs 15% in northernmost locations, 26% vs. 19% in central (between 31 and 35°S) and 28% vs. 1% in southernmost locations, respectively. A curvilinear relationship emerged between the monthly probability of combined stresses and the number of days with stress per month. In summary, T > 30 °C was the most frequent thermal stress during post-flowering in wheat and canola. Both combined stresses had a noticeable risk of occurrence, but T > 30 °C plus R50% was the highest. Evidence of the recent past and current occurrence of heat stress individually, and its combination with cloudiness events during post-flowering of temperate crops, serves as a baseline for future climate scenarios in main cropped areas in the Southern Cone of South America.

TIBA and nitrogen incorporation, senescense and yield in a symbiotically grown vining dry bean (Phaseolus vulgaris L.) genotype

The growth regulator 2, 3, 5 triiodobenzoic add (TIBA) was applied foliarly at the beginning of flowering (R1 stage) to a vining dry bean (Phaseolus vulgaris L.) genotype, grown symbiotically in a low nitrogen containing soil. Profiles of root nodule nitrogenase and leaf nitrate reductase activities, as well as of leaf chlorophyll content throughout the postflowering period, indicate that TIBA reduced the duration of nitrogen incorporation and caused early senescence. An increase in the number of pods per plant as well as in dry matter harvest index, supports the theory that TIBA causes bean plants to shift from vegetative to reproductive growth. No seed yield increase occurred as a result of TIBA application. Symbiotic nitrogen fixation alone may not provide sufficient nitrogen to allow optimal development of an increased number of pods. Further trials under higher soil nitrogen levels are suggested.

The Effect of Different Phenological Periods and Harvest Times on the Essential Oil Ratio and Components of Basil Genotypes

The basil is an annual medicinal plant that can be harvested more than once in the growing season. This study aimed to examine the variation of essential oil ratios and components of five different basil genotypes harvested in different phenological periods (pre-flowering, full-flowering, and post-flowering periods.). When the basil was harvested in the pre-flowering period, it could be harvested three times. In parcels left to full-flowering, basil genotypes have reached full-flowering twice in one vegetation period. The parcels left to the post-flowering period were harvested once. Essential oils were obtained separately from the flowers and leaves of the plants by hydrodistillation. Essential oil ratios in flowers and leaves for all phenological periods varied between 0.28-3.19 %. The ratio of essential oil in the parcels with multiple harvests was higher in the second and third harvests compared to the first harvest. It was determined that the ratio of essential oil in the parcels with multiple harvests was higher in the second and third harvests compared to the first harvest. The main components of the basil genotypes were determined as linalool, methyl cinnamate, eugenol, g-muurolene, and eucalyptol in all harvesting periods. In the post-flowering period harvested once, the linalool ratio of the basil genotypes ranged from 20.32-54.63 %. On the other hand, methyl cinnamate could not be detected in some genotypes like in the two and three times harvests, the highest ratio was found as 46.10 %. The linalool ratio of genotypes harvested twice in the full flowering period varied between 24.20-65.91 %, while the methyl cinnamate in some genotypes ranged from 0.04 to 53.26 %. The linalool ratio in the parcels with three times harvests in the pre-flowering period varied between 22.47-59.0 %. The methyl cinnamate ratio varied between 0.04-51.38 %. It was determined that the proportions of the main components decreased in the second and third harvests in the parcels harvested more than once.

Does the photo-thermal environment limit post-flowering maize growth?

After canopy closure and in the absence of limitations by water or nutrient availability, crop growth rate (CGR) of maize (Zea mays L.) is ultimately constrained by the daily incident radiation and temperature of the environment. Sustaining maximal canopy photosynthetic capacity after-flowering is, then, a necessary but not a sufficient condition to increase maize dry-matter production. The aim of the present study was to determine the extent of the photo-thermal environment limitation to CGR during the post-flowering period in current maize crops. Dynamic of CGR was studied in two well-irrigated and nourished maize field experiments (Exp. 1 and Exp. 2 for 2010−11 and 2011−12 cropping seasons, respectively) on conventional crops (i.e. full-season hybrid planted early in the season) at Balcarce, Argentina (37° 45’ S, 58° 18’ W; 130 m a.s.l.). Two independent methods were performed to benchmark the CGR of these conventional crops during the post-flowering period: i) empirical CGR values obtained under the same weather conditions from younger maize crops, and ii) theoretically estimated potential CGR, obtained as a function of daily incident radiation and potential radiation use-efficiency (RUE). Conventional crops reached the maximal CGR near flowering in mid-January, being 51.2 g m−2 d−1 and 58.8 g m−2 d−1 in Exp. 1 and Exp. 2, respectively. Afterwards, CGR decreased progressively towards crops maturity late in March. Estimates, from either the empirical or the theoretical method, indicated that although attainable-CGR decreases progressively towards the end of the cropping season, it sustains higher values than those achieved by conventional crops after flowering. Differences in attainable vs. actual-CGR was almost exclusively attributable to RUE, which, in turn, could not be explained solely by the post-flowering foliar nitrogen withdrawal. Differences between actual (1987 g m−2 in Exp. 1 and 1614 g m−2 in Exp. 2) and potential post-flowering dry-matter production defined gaps that were in the range 18.2%–47.8%. From these results, it can be concluded that the photo-thermal environment is not, at least so far, the limiting factor to the post-flowering maize growth. Further research is needed, however, to analyze the viability of increasing potential yield of maize through the closure of these estimated gaps.

Adjusting sowing date and cultivar shift improve maize adaption to climate change in China

This study investigates the impact of climate change on spring and summer maize (Zea mays) yield and evaluates several adaptation measures to overcome the negative impact of climate change on maize production in China. The results showed that the grain-filling duration of maize would be shortened 6–15 days in the future as a result of climate change. Thus, potential maize yield would decrease by 2–32%, and rainfed maize yield would decrease by 0–24% during 2010–2099 relative to 1976–2005. In response to climate change, adaptive measures should be taken to overcome its projected impact. The adoption of new cultivars while maintaining the same pre-flowering and post-flowering duration in the future as in the present would help to improve potential maize yield by 50–61% in three time slices (2030s, 2050s, and 2070s) and would be a better choice for high yields in the future. The cultivars that would maintain the same post-flowering duration in the future as in the present would be a better choice than the cultivars that would maintain the pre-flowing periods for summer maize in China. Adjusting sowing dates would be another important way to extend post-flowering periods and further improve maize yield. If the maize cultivar currently used was adopted, delaying the sowing date would improve the potential maize yield by 2–25%. If future maize cultivars that maintained the growing period even as warmer temperatures accelerate phenological development were adopted, delaying the sowing date would improve the potential maize yield by 0–8.9%. The interactive effect of sowing and cultivars was quantified. Based on the findings of this study, future maize cultivars maintaining the growing period were adopted, and delaying the sowing date could still improve potential maize yield worldwide. Two regional adaptation strategies to climate change could offset the potential reduction of maize production worldwide, which would provide farmers and policy-makers with explicit guidance.

Genotype × environment interaction on the yield of spring oilseed rape (Brassica napus) under rainfed conditions in Argentine Pampas

AbstractOilseed rape seed yield has increased in the last 40 years in most countries, but this yield gain has not been accompanied by greater yield stability. The current study aimed to quantify the genotype by environment (G × E) interaction on oilseed rape yield, identify genotypes with broad adaptability and the main environmental drivers related to seed yield. A weighted two-stage mixed-model analysis was applied to official multi-environment trials of nine spring genotypes (G), in three locations (L) during 6 years (Y) on central and southern Argentine Pampas under rainfed conditions. Best linear unbiased prediction of seed yield ranged from 0.37 to 3.73 kg/ha. Fixed effect L × Y was highly significant and G variability was estimated as 130 kg/ha of standard deviation. Contrasting genotypes were identified by Shukla's stability index and two of those showed the best yield performance in the wettest year. Factor analysis explained 0.75 of total variation and discriminated genotypes with broad and specific adaptability, as well as combined environments according to the similarities in seed yield of the evaluated genotypes. Environmental loadings of Factor 2 were linearly associated with cumulative rainfall in the post-flowering period (up to 230 mm). It is concluded that (i) a significant G × L × Y interaction underlies the high variability of seed yield, (ii) two genotypes (G6 and G7) with high yield stability were identified, and (iii) G × E effects are associated with post-flowering rainfall.

Different Sources and Concentrations of 6-BA in Chemical Thinning of Post-flowering in Apple Trees

Aims: Evaluate the efficiency of sources and dosages of 6-benzyladenine in the chemical thinning of the apple tree ‘Fuji Suprema’, as well as possible histological changes in the fruits produced, in the Midwestern region of the state of Santa Catarina.
 Study Design: The experiment was arranged in a randomized block design and replicated six replications.
 Place and Duration of Study: The experiment was carried out in the municipality of Caçador, Brazil (latitude 26º46 'S, longitude 51º W, altitude 960 meters), during the growing season of 2016/2017.
 Methodology: Two commercial products based on 6-BA (Benzyladenine), Exilis® and Maxcel®, both with 2% BA in their composition, were tested and applied individually in post-flowering period (in fruits of 5-10 mm), which were compared with plants with no thinning and manual thinning. Treatments were as follows: Control (no thinning); manual thinning; Exilis® (1.5, 3.0, 4.5 and 6.0 L ha-1) and Maxcel® 4.5 L ha-1), using a spray volume equivalent to 1000 L ha-1. The fruit set and the number of fruit per cm2 branch, was reduced in treated plants, regardless of the concentration of BA or formulation used. The productivity ranged from 38 to 56.5 t ha-1 in the treatments of Exilis®, 60.5 t ha-1 in manual scaling and 24.5 t ha-1 in the Maxcel® 4.5 L ha-1, characterizing excessive thinning. BA is efficient in fruit thinning in 'Fuji Suprema' apple trees, being the reduction of fruiting, and increase of fruit size, proportional to the applied concentration. There may be differentiated efficiency of the product by its formulation, even though they have concentrations of active ingredient equivalent. Exilis® was efficient in thinning of apple "Fuji Supreme", when applied to fruit 5 to 10 mm in diameter reduced the need for manual thinning, without causing toxicity. BA can promote the increase in the cell density of fruits produced in proportion to the applied concentration.

Influence of Post-Flowering Chemical Thinning on Development and Fruit Quality of 'Fuji Suprema' and 'Maxigala' Apple Trees

Aims: Evaluate possible alterations in the development, anatomy and quality of fruits from 'Maxi Gala' and 'Fuji Suprema' apple plants treated with Metamitrom (MM) and Benzyladenine (BA) alone or in combination, applied at different stages of fruit development in the Midwestern region of the state of Santa Catarina.
 Study Design: The experiment was arranged in a randomized block design with five replicates. Place and duration of Study: The experiment was carried out in the municipality of Caçador-SC, Brazil, during the growing season of 2016/2017.
 Methodology: Two products, BA (with hormonal action) and MM (photosynthesis inhibitor) were applied individually or in a tank mix in post-flowering periods (in fruits of 5-10 mm and 15-20 mm in equatorial diameter), which were compared with plants with no thinning and manual thinning of both cultivars. Treatments were as follows: Control (no thinning) MM, BA, MM + BA (in fruits of 5-10 mm in diameter); MM, BA, MM + BA, manual thinning (in fruits of 15-20 mm in diameter). The phenological stage of F2 (Full flowering (FF) was observed on September 28, 2016 for both cultivars. Evaluations of the anatomical characteristics of fruits at the time of harvest did not show any alteration in cell size (mean cell area - μm2) and cell density (number of cells per fruit section area); the mean fruit mass was higher in MM 350 mg L-1 (5-10 mm), MM 350 mg L-1 + BA 40 mg L-1 (5-10 mm), and MM 350 mg L-1 (15-20mm) treatments. In the 'Fuji Suprema' cultivar, except for control treatments, MM 350 mg L-1 (5-10mm) and BA 80 mg L-1 (5-10mm), a significant reduction in production was observed (kg plant-1 and fruit-1). While in 'MaxiGala', all the thinning treatments reduced yield per plant. The cultural thinning practice, fruit load management, adapting the number of fruits according to plant size is the most important factor that producers are able to influence. Thinning reduces fruit load in the plant, which allows remaining fruits the possibility of greater growth and size gain. The combination of MM + BA is efficient in the thinning of apple fruits, especially when applied at the beginning of fruit development (5-10 mm in diameter). The application of chemical thinners, such as MM and BA, may influence the early stages of fruit development.

Maize–fababean rotation under double ridge and furrows with plastic mulching alleviates soil water depletion

Double ridge and furrows with plastic mulching (PM), an effective drought-resistant farming technology, has been widely used in the semi-arid areas of China, and increased crop yields by more than 30%. However, where this technology has been applied in successive years, the annual balance of soil water has been affected and the risk of soil desiccation exacerbated. A 6-year field experiment had been conducted on the semiarid Loess Plateau to find a new mode of ecological security and economic efficiency under PM conditions. The two treatments were (i) PM with continuous maize cropping (PM-C) and (ii) PM with maize–fababean rotation (PM-R). The vertical variation of soil water along profile and the interannual variation of soil water, cumulative water consumption, biomass and yield, benefit and water economic yield were investigated. The results showed that the depth of soil water consumption of PM-C was extended downward by 60 cm from 2009 to 2014, but it did not vary in PM-R; the maximum depth of soil water consumption were 280 cm and 220 cm in PM-C and PM-R, respectively. Compared with the pre-seeding stage in 2009, soil water storage in the 0–300 cm depth in 2014-HA for PM-C decreased by 163.59 mm, comprising 5.21 mm in the 0–140 cm soil layer and 158.37 mm in the 140–300 cm layer. However, in the PM-R treatment, the soil water storage in the 0–300 cm depth in 2014-HA increased by 28.36 mm, resulting from an increase of 47.86 mm in the 0–140 cm soil layer and a decrease of 19.50 mm in the 140–300 cm layer. PM-R significantly improved crop water consumption in the post-flowering period, and the ratio of water consumption in post-flowering to total significantly increased by 19.54–51.09% (P < 0.05). The biomass and grain yield for PM-R were significantly lower than for PM-C, by 21.36 and 59.14%, respectively. However, there were no significant differences in benefit, mainly because the price of fababean was higher. The soil water depletion in 6 years of PM-R decreased significantly and therefore water economic yield was significantly higher than for PM-C. This suggested that PM-R alleviated the over-consumption of deep soil water and the water depletion depth, which caused by continuous maize cropping in PM-C, and so achieved significantly higher water economic yield by reducing soil water depletion and provided stable economic benefit. Consequently, PM-R represents a sustainable ecological, economic, secure and replicable planting mode.

Researches on hybrid Phlomis x termessi P.H. Davis in Göynük province of Antalya

In this study that was conducted during the vegetation period of 2016, determination to morphological characteristics and volatile components in volatile components in the leaves and flowers of Phlomis x termessi P.H. Davis were aimed. For determining to volatile components leaves and flowers were collected from Göynük-Antalya in three different periods that were pre-flowering, flowering and post-flowering periods and volatile components were determined through SPME (solid-phase microextraction method) analysis. 57 different volatile components were identified from P. x termessi, while it was also found that the rate of volatile components was higher during the flowering period, and α.-pinene, limonene, β- caryophyllene and germacrene-D were found to be the main components. Furthermore, with a view to measuring the morphological features of P. x termessi, width-height of 50 leaf samples and the length of leaf stalks were measured; while the calyx height of 50 calyxes samples collected, the length of calyx teeth, bracteole length and the length of corolla were measured and the mean values were calculated. As result of morphological characteristics, means of leaf length, leaf width, petiole, calyx, calyx teeth, bracteole and corolla were measured as 4.55±1.65, 1.78±0.89, 2.56±1.55, 1.17±0.18, 0.35±0.11, 1.31±0.40 and 2.04±0.30 respectively.