Early Sowing Time Research Articles

Crop Density and Sowing Timing Effect on Tan Spot Occurrence in Spring Wheat

Tan spot (Pyrenophora tritici-repentis) is presenting a persistent challenge to the plant health and yield of all wheat-growing regions. This research is focused on tan spot disease management in spring wheat when planted at three distinct times and with three different seeding rates without the use of fungicides. Across all years, higher seed rates (500 and 600 seeds per m2) generally resulted in lower tan spot intensity compared to the lower seed rate (400 seeds per m2). Significant differences in tan spot intensity were observed across seed rates at all sowing times. In 2021, the percentage of the AUDPC was significantly higher in the late sowing time (324.58%), with about a 2-fold difference compared with the early (167.48%) and optimal sowing time (191.80%). This suggests that delayed sowing significantly exacerbates disease occurrence. The combined effect of sowing time and year on the AUDPC was notably significant. The AUDPC of the tan spot in all seed rates was the highest in the late sowing time plots in comparison to the ideal and initial planting dates plots. Our results demonstrate how important seed rate and sowing timing are in determining the degree of tan spot in spring wheat. Growing crop methods may be improved by taking these elements into account to better control tan spots. More agricultural methods and environmental aspects should be investigated in future studies to create all-encompassing tan spot control plans.

Sowing Date and Seed Rate Influence on Septoria Leaf Blotch Occurrence in Winter Wheat

Septoria leaf blotch (SLB), caused by Zymoseptoria tritici, is one of the most important foliar diseases of wheat. The management of this disease is assisted by selecting a sowing time and seeding density that is less favorable to the pathogen. The aim of this research was to evaluate the severity of SLB on winter wheat cv. ‘Etana’ sown at three different sowing times and three seed rates. The severity assessments were performed on the upper two leaves three times during the growth stages using the phenological growth stage key developed by the Biologische Bundesanstalt, Bundessortenamt, and Chemical industry (BBCH), namely stages 37–41, 59–65, and 75. The area under the disease progress curve (AUDPC) was evaluated in each plot. In 2022, seed rates showed significant differences (p = 0.0047), while sowing times did not show significant differences. In contrast, both seed rate and sowing time showed significant effects in 2021 (p = 0.0004 for sowing time and p < 0.0001 for seed rate). During the 2021 growth stage BBCH 75, late sowing times exhibited a significant reduction in SLB on the first leaf. The reduction ranged from 47.0% to 52.6% compared to the optimal sowing time, and from 59.2% to 66.2% compared to the early sowing time. At optimal sowing times (between 11 September and 25 September), seed rates of 400 and 450 seeds/m2 resulted in a low SLB. At late sowing times in 2022, a lower SLB (43.2% compared to the early sowing time) was obtained from seed rates of 400 seeds/m2. No significant interaction was observed between sowing time and seed rate across both study years. In the absence of interaction, the effects of sowing time and seed rate on SLB severity were independent and not additive. In 2022, the highest values of AUDPC were recorded for the early sowing time and the highest seed rate. Increasing the seed rate (450 seeds m−2) gave higher AUDPC at early sowing time with significant differences compared to other seed rates at optimal or late sowing times. In conclusion, our findings highlight the significant influence of sowing time and seed rate on SLB severity in winter wheat. Understanding these factors can inform agricultural practices to better manage SLB. Future research should explore additional agronomic practices and environmental factors to develop comprehensive strategies for SLB management.

Improving the elements of cultivating technology for Sarepta mustard (Brassica juncea L.) on leached blackearth of Western Ciscaucasia

Increasing interest among agricultural producers in Sarepta spring mustard as a promising, multi-purpose crop requires improving the elements of its cultivation technology to obtain consistently high yields. The current study was carried out in 2021–2022 on the experimental fields of the central experimental base of the FSBSI “FRC “All-Russian Scientific Research Institute of Oil Crops by the name of Pustovoit V. S.”. The purpose of the research was to study and scientifically substantiate individual elements of the technology (sowing time, seed sowing rate and level of mineral nutrition) for Sarepta mustard’s cultivation on seed productivity of the crop grown on leached blackearth (chernozem) of Western Ciscaucasia. There has been established that the highest yield (1.42 t/ha) and oil yield (0.60 t/ha) of the crop is obtained at an early sowing time (the first term (early) is in the 2nd decade of April) with a minimum seed sowing rate (1.3 million units/ha). Sarepta spring mustard’s single feeding of with ammonium nitrate at a dose of N60 in the seedling phase has helped to obtain maximum yield of 2.08 t/ha and 0.87 t/ha of oil. But the largest oil content in seeds (47.1 %) was identified in the variant with the application of nitrogen fertilizer at a dose of N30 fractionally in equal parts, i.e. in the stages of germination (N15) and booting (N15). Foliar treatment of Sarepta spring mustard with helium mixtures (Micro gel at a dose of 1 l/ha and Brassica gel at a dose of 2 l/ha) in the booting stage allowed obtaining the highest yield of 1.85 t/ha, with 47.9 % of oil in seeds and 0.80 t/ha of oil yield.

Evaluation of the quantitative and qualitative characteristics of sugar beet cultivars in different sowing times and transplanting and direct-seeding systems

To study the characteristics of sugar beet cultivars in transplanting and direct-seeding systems on three different sowing times (March 29, April 8, and April 18), a split plot experiment based on randomized complete blocks in three replications was carried out in Miandoab and Bokan regions, Northwest of Iran in 2016. The results showed that the highest nitrogen content was observed between the two test locations in the Bukan area. Results showed that the low root sodium, alkalinity, and molasses content was recorded for transplanting system. The minimum content of root sodium, nitrogen, and molasses sugar was observed in the plants sown on March 29. The Dorotea cultivar showed the highest root yield, sugar yield, and white sugar yield and the lowest root nitrogen and molasses sugar content compared to Isabella and Ekbatan. The highest white sugar content, coefficient of sugar extraction, sugar yield, root yield, and white sugar yield were recorded in the transplanting system with the sowing time of March 29; however, the highest content of root potassium and sugar content was observed in the transplanting system sown on April 18. The highest root yield was observed in the Dorotea cultivar, with a sowing time of March 29. Among the locations in the cultivar and planting system interaction treatments, the highest sugar content was found in the Bukan area's Dorotea cultivar in the transplanting system. Finally, the highest sugar yield was related to the transplanting system on March 29 in the Bukan area. It can be stated that an early sowing time (March 29), transplanting, and Dorotea variety were identified as the most appropriate treatments to improve the economic traits of sugar beet.

The Impact of Sowing Time and Biostimulant Application on Seed Production in Italian Ryegrass

This research was performed to determine the effects of different sowing times (ST1, ST2, and ST3) and biostimulant (Pi-NFS) doses (0, 100, 250, 500 ml da-1) on seed yield components of Italian ryegrass ryegrass (Lolium multiflorum L.) in the continental condition of Eskişehir, Turkey. The results indicated that the main factors significantly affected the seed yield components except for the effect of sowing time on plant height, however, the interaction effect of these factors was significant only on the number of the reproductive tillers and seed yield. There was no significant difference between the ST1 and ST2 in terms of the number of the reproductive tillers, thousand seed weight, and seed yield. Likewise, the values of these components did not differ significantly in the doses of 250 and 500 ml da-1. The highest seed yield was derived from the dose of 500 ml da-1 at ST2 and the values obtained from the doses of 250 and 500 ml da-1 at the ST1 were in the high seed yield group. It was concluded that early sowing time and the doses of 250 to 500 ml da-1 biostimulant application resulted in high seed yield in Italian grass. On the other hand, the dose of 500 ml was more effective in case of delayed sowing time like ST2.

Earlier sowing combined with nitrogen fertilization to adapt to climate change effects on yield of winter wheat in arid environments: Results from a field and modeling study

Climate change effects on crop production are of high concern in arid regions that are suffering from increased drought. We parameterized the APSIM-Wheat (The Agricultural Production Systems sIMulator) model using data of two field experiments conducted in 2017 at two locations (Karaj and Khomein) in Iran differing in temperature and precipitation. The experiment was a split plot with four replications. Main plots measured 17 m by 5 m with four irrigation regimes of full irrigation (I1), deficit irrigation from grain filling (I2,), from beginning of flowering (I2), and during the whole growth period (I4). Sub-plots measured 3 m by 5 m with nitrogen (N) levels of 200 (N1), 100 (N2) and 50 (N3) kg/ha of urea (46 % N). N1 resulted in highest wheat biomass, grain yield, harvesting index and leaf area index (LAI), with the differences between the N levels decreasing with increasing water deficit period. The model was parameterized for both localities with data of treatment I1 +N1, then evaluated over 11 combinations of irrigation and nitrogen rates. Root mean square of errors (RMSE) were 0.3 and 0.15 t/ha for wheat biomass and grain yield, and 3.54 days for wheat phenology and 0.28 for LAI simulations. After model calibration, we ran the model with 20 general circulation models (GCMs) under two representative concentration pathways (RCP 4.5 and RCP 8.5), and crop production was projected for three future time periods. For 2010–2039, models simulate a marginal increase in wheat yield, however, with 2040–2069 and 2070–2099, most models simulate a decreased growing season length and grain yield. Nitrogen application was found to decrease the drought impact. Additionally, model simulation suggests that earlier sowing time and excessive irrigation are of benefit in adapting to climate change impact. Thus, in arid environments where additional irrigation is not an option, increased nitrogen application in combination with an earlier sowing time could be an effective adaptation strategy for future wheat production.

Role of priority effects in invasive plant species management: Early arrival of native seeds guarantees the containment of invasion by Giant ragweed.

Empirical evidence shows that early arrival of native species, which induces the priority effects, can contribute to invasive plant species containment. However, more systematic studies are required to test the applied relevance of the priority effect. This study therefore aimed at testing the priority effects generated by different sowing times of seeds of nine native species on one target invasive plant species, that is, Giant ragweed (Ambrosia trifida). This study hypothesized that, when sown earlier, some native species will be able to substantially contain A. trifida through resource preemption. An additive competition design was used to test the competitive effects of native species on A. trifida. Depending on the sowing times of native and invasive plant species, three priority treatments were conducted: all species sown at the same time (T1); native species sown 3 weeks before A. trifida (T2); and native species sown 6 weeks before A. trifida (T3). Priority effects created by all nine native species significantly affected the invasibility of A. trifida. The average value of the relative competition index (RCIavg) of A. trifida was the highest when native seeds were sown 6 weeks early and decreased with decreasing early sowing time of native plants. The species identity effect was not significant on RCIavg if natives were sown at the same time or 3 weeks earlier than A. trifida invasion, but it was significant (p=.0123) if they were sown 6 weeks earlier than A. trifida. Synthesis and applications. The findings of this study clearly show that native species, when sown early, provide strong competition and resist invasion through prior utilization of resources. The consideration of this knowledge might improve A. trifida invasion management practices.

The Impact of the Sowing Time on Peanuts Yield`s Components in Marginal Sandy Soils in Southern Oltenia, Romania

Marginal sandy soils are frequently characterized by low fertility, low organic matter, moderate to high acidity and low cationic exchange capacity, limiting the options of smallholding farmers for various crops. To investigate the impact of the sowing time on grain yield, yield components, protein and oil content of peanuts cultivated in marginal sandy soils in Southern Oltenia, Romania, a bifactorial experiment in a randomized complete block design with three replications was conducted during 2015-2017 at the Research Development Station for Plant Culture on Sands Dăbuleni. The first factor was sowing time (the 25th April as early sowing and the 5th May as late sowing) and the second factor was peanut cultivar (Dăbuleni, Viorica, Viviana). According to the results of the experiment the sowing time had significant impact on the pods number per plant, the production of pods and the grain oil content. Analyzing the interaction between the sowing time and the cultivar there were significant differences only in the pod number per plant in 2015 and the production of pods in 2016. In all peanut’s genotypes studied, early sowing led to higher yields of pods compared to late sowing, probably due to the shortening of the vegetation period of the crop by late sowing on the 5th May, which led also to less dry matter and lower oil content accumulated in peanut grains. Therefore, the results suggested that early sowing time is the most recommended for peanuts growth and quality yield in sandy marginal areas.

Determination of Yield and Yield Components of Chickpea Varieties Grown in Winter and Early Spring in Sırnak-Idil Conditions

The aim of this study was to determine chickpea varieties that can be grown at different sowing times in Şırnak-Idil conditions and their important agricultural and vegetative properties. The study was carried out in two sowing times (winter and early spring) with 10 chickpea varieties (Azkan, Arda, Aksu, Botan, Hasanbey, Arslanbey, Caner, Onur, Seçkin and Sezgin) according to the randomized complete blocks, split plot experimental design, with 3 replications, sowing times as main plots, varieties as subplots in 2020/2021 growing season. As a result of the research, in different growing periods of various chickpea varieties the number of days until flowering; plant height, first pod height, number of branches, number of pods, hundred seed weight, and seed yield varied between 77.83 and 147.03 days, between 30.52 and 39.65 cm, between 19.33 and 19.96 cm, between 2.89 and 3.01 per plant, between 10.46 and 27.38 per plant, between 33.28 and 37.75 g and between 78.34 and 112.41 kg da-1, respectively. As a result of the research, it was determined that winter sowing time were superior to early spring sowing time in terms of yield and yield components. Winter sowing time can be recommended in similar ecologies where the research is carried out. In addition, Aksu, Hasanbey, Sezgin and Onur cultivars in the study were superior to other cultivars in the year the experiment was conducted in terms of yield and some yield-related characteristics.

Značaj suzbijanja korova i roka sjetve u proizvodnji kivana (Cucumis metuliferus E. Meyer Ex. Naudin) na području istočne Slavonije

Seed germination, growth, flowering and yields of kiwano (Cucumis metuliferus E. Meyer Ex. Naudin) were examined in eastern Slavonia during 2021 growing season. The objective of this study was to determine agro-morphological diversity within kiwano growing under different weed management practices and sowing time. The experiment was arranged as a 3 x 3 factorial design with three replications. Factors included three weed management options (wheat straw mulch, cultivation and un-weeded control) and three planting dates (early, mid and late May). A typical summer weed community that develops during experiment dominated with bristly foxtail (Setaria verticilata (L.) P. Beauv.) and redroot pigweed (Amaranthus retroflexus L.) while the others were with lower relative density and frequency per unit area and with the lower impact on the crop. Weed control was very effective compared to weedy check. However, sowing date appears as a critical factor in kiwano production, influencing not only emergence, growth and flowering, but also fruit number and size. This study concluded that mid sowing time and cultivation as a weed control measure has a highest agronomic potential for a kiwano production following by mid and early sowing time with mulch as a weed control measure.

The Influence of Different Seeding Application Rates and Sowing Time on Maize Hybrids’ Productivity in the Conditions of the Republic of Bashkortostan’s Southern Forest-Steppe Zone

Maize takes the leading place in yield and is one of the most common crops in the world. Selection of the optimal seeding application rate and time is among the central issues in maize cultivation technology and is highly relevant. The research made in 2018–2020 aimed at improving the maize technology block for grain (seeding application rate and sowing time, southern forest-steppe, the Republic of Bashkortostan). For this purpose, a field experiment was launched in a fourfold replication. The experimental design included hybrids: Nur, Mashuk 171, Baikal and Mashuk 220 with a planting density of 60 (control), 70, 80, and 90 thousand pcs/ha. The experiment revealed a high correlation dependence of the yield of green mass and grain on the sowing time (r = 0.876–0.915 and r = 0.951–0.963). In the conditions of the Republic of Bashkortostan’s southern forest-steppe, Baikal and Mashuk 171 hybrids are recommended to be used for animals and poultry diets and the planning of maize cultivation technological schemes at early sowing time (May 10) and a seeding application rate of 80 thousand pcs/ha. The results of the research apply to the formation of agricultural feeding diets.

Agronomic interventions affect the growth, yield, and essential oil composition of German chamomile (Matricaria chamomilla L.) in the western Himalaya

German chamomile (Matricaria chamomilla L.) makes favourable use of environmental conditions when sown at the optimum time; however, less information is there in the literature about agronomic interventions in the Indian western Himalaya. Therefore, a field study was conducted for two successive years (2018-2019 and 2019-2020) to examine the effects of agronomic interventions on agro-morphological characters, essential oil (EO) yield, and chemical constituents of German chamomile cultivated in the Indian western Himalayan region. The experiment consisted of twelve treatments comprising of four sowing times (November 20, December 10, December 30, and January 20) in combination with foliar application of 3 salicylic acid (SA) levels (0 ppm, 25 ppm, and 50 ppm) replicated thrice in a factorial complete randomized block design (FRBD). Agro-morphological and yield characteristics were significantly higher in early sowing and SA applications but decreased with later sowing times. Days taken to develop each development stage declined with late sowing and vice-versa, while essential oil yield was 29.96 and 8.99% higher in early sowing (November 20) and 50 ppm SA application, respectively. Significantly higher α- bisabolol oxide A (5.80%) and bisabolone oxide A (14.74%) were recorded in late sowing (January 20) and early sowing time (November 20), respectively. The outcomes from the study presents innovative knowledge, a solution for farmers and industrialists to satisfactorily produce German chamomile by sowing at the proper time to get maximum yield and quality essential oil.

Effect of future climate change on the water footprint of major crops in southern Tajikistan

Danghara, a major food production area in southern Tajikistan, is currently suffering from the impact of rapid climate change and intensive human activities. Assessing the future impact of climate change on crop water requirements (CWRs) for the current growing period and defining the optimal sowing date to reduce future crop water demand are essential for local/regional water and food planning. Therefore, this study attempted to analyze possible future climate change effects on the water requirements of major crops using the statistical downscaling method in the Danghara District to simulate the future temperature and precipitation for two future periods (2021–2050 and 2051–2080), under three representative concentration pathways (RCP2.6, RCP4.5, and RCP8.5) according to the CanESM2 global climate model. The water footprint (WFP) of major crops was calculated as a measure of their CWRs. The increased projection of precipitation and temperature probably caused an increase in the main crop’s WFP for the current growing period, which was mainly due to the green water (GW) component in the long term and a decrease in the blue water (BW) component during the second future period, except for cotton, where all components were predicted to remain stable. Under three scenarios for the two future periods, a 10 ​d early sowing time was defined as an optimal sowing date, in which the WFPs of potato and winter wheat decreased from 5.7% to 4.8% and 3.4% to 2.2%, respectively. Although the WFP of cotton demonstrated a stable increase, according to the optimal sowing date, a decrease in irrigation demand or BW was expected. The results of our study might be useful for developing a new strategy related to irrigation systems and could help to find a balance between water and food for environmental water demands and human use.

Cold stress at seedlings stage of buckwheat optimizes development of both roots and aboveground biomass and limits the excessive vegetative growth interfering with seed formation (an analytical review)

Buckwheat, sown in warmed soil, quickly sprouts, grows and successfully competes with annual weeds. However, such agronomic practice does not always lead to a good grain yield, because a powerful, abundantly flowering buckwheat plants often give only a minimal amount of seeds due to a lack of moisture in the upper layer of soil during flowering. This behavior of buckwheat is described as "overgrowth (with poor seed formation)". This phenomenon is caused by the relative weakness of the root system of this species: the specific feature of buckwheat is a very fast transition to formation of secondary roots, which gives advantages at the first stages of development, but restricts the roots growth later. Buckwheat flowering is stretched in time. First half of this developmental stage which is most important for the grain yield is coincided with the most intensive vegetative growth. The lowered temperature at the seedlings stages slows the growth of the aboveground biomass and accelerates the growth of the roots that at later stages favorably affects the conditions for seeds development and, respectively, the grain yield. It explains why early sowing time is favorable for the grain yield of buckwheat.

Effects of Environment and Sowing Time on Growth and Yield of Upland Cotton (Gossypium hirsutum L.) Cultivars in Sicily (Italy)

Cotton is one of the most important industrial crops in the world. Though widely cultivated in Sicily (Italy) in the past, cotton growth on the island has disappeared today due to a complex variety of agronomic, economic and socio-political reasons. In recent years, increased interest in natural fibers worldwide has led to a revival in cotton plants in the Mediterranean area. The aim of this paper was to assess the response of Gossypium hirsutum L. cultivars to different environments and sowing times. Elsa and Juncal were selected from the most promising cotton cultivars regarding earliness and productivity. Plants were tested with three sowing times and in two Sicilian environments. Cotton yield and yield components were significantly affected by experimental station, sowing time and cultivar. Lint yield of cultivars was 1.60 t ha−1 on average, and the highest value of 1.99 t ha−1 was obtained from an early sowing time. The three indices of agronomic earliness varied significantly based on treatments. In conclusion, the evaluation of response genotype-by-environment under different sowing times could represent a strategy to obtain optimal cotton seed and lint yields, although other general aspects, such as labor costs, land availability and capital resources, should be also considered when evaluating the reintroduction of the species in Sicily.

Effect of weed control technologies on chickpeas (Cicer arietinum L.) and weeds

Purpose. In our experiment, effect of weed technologies on chickpeas (Cicer arietium L.) was set up in 2018 and 2019 at the Szeged-Othalom experimental area.Methods. In the first year we applied mechanical weed control in addition to pre-emergence herbicide (May 19, 2018) and 6–8 leaf chickpeas (June 20, 2018) in addition to post-emergence herbicide treatments. The year 2019 was different in that after the pre-emergence treatment (April 10, 2019), the post-emergence treatment of chickpeas with 6–8 leaf condition (May 15, 2019) was repeated in the budding state (June 18, 2019). The yield components one way analysis of variance was prepared using SPSS 22 software and graphic representation of the development of the plants was carried out Svab's cumulative yield analysis.Results. The effect of the treatments of 2018 and 2019 on the yield elements of chickpeas can be illustrated graphically in Figure 1 and Figure 2. For both years, the data are from plots of the ʻRealeʼ variety, where the 100% level is made up of the yield elements of the weed-free plots, and the yield elements of the other treatments are compared to this. Figure 1 shows that the number of shoots per unit area (1 m2) of weed-free plots that did not control weeds was 15%, the number of pods 45%, the number of seeds 58% and the weight of seeds 49% less than the weed-free control plots the same crop elements. Weeds were also significantly present in the plots treated only with pre-emergence treatment in the second half of the growing season, so the number of shoots per unit area was 3 %, the number of pods 23 %, the number of seeds 34% and the seed weight 35 % lower, as on weed-free plots. In the case of herbicide treatments, the decrease in yield elements was much smaller: the number of plants per unit area by 1%, the number of shoots by 3–10%, the number of pods by 5–12%, the number of seeds by 13–18%, the seed weight was by 1–5% less than on mechanically weed-controlled plots. Conclusions. Our two-year weed survey results show that the later sowing time of chickpeas favored warm-loving weeds. This is in complete agreement with the opinion of Nagy (2017), who found that sowing time determines the predominant weed species in a given area. At the same time, the statement of Kurnik (1970) was not confirmed, since in our experiment we proved in the case of ʻRealeʼ cultivar that the later sowing stock in 2018 gave higher yields than the plots with earlier sowing time in 2019. The changing weather caused by climate change makes the site characteristics of the given period much more unpredictable, so the yield is determined much more by the field factors developed during the growing season than by the calendar period.

Results and prospects of European radish breeding

Relevance Currently, the first place goes to the creation of new high-yielding varieties and hybrids F1 crops that meet the requirements of modern industrial technologies. Heterosis hybrids have high yield, marketability, equalization, friendly yield and resistance to disease. Methods When developing new varieties and hybrids of radish suitable for mechanized harvesting, attention should be paid to the strength of the attachment of the leaf outlet and its upright position, the uniformity of immersion in the soil and the easy pull-out of root crops. Studies were performed in a protected (heated film greenhouse) and open ground in All-Russian Scientific Research Institute of Vegetable Growing – Branch of the FSBSI Federal Scientific Vegetable Center. Results The results of breeding work with European radish are presented. According to the results of expert evaluation, the state register of breeding achievements included two varieties of European summer radish – Bianca, Sirius and one hybrid of European winter radish – Tsyganskiy Baron F1. The new varieties are distinguished by uniformity in shape, length, diameter of the root crop, compact leaf rosette, form a root crop in a short and long daylight, recommended for cultivation under film shelters and in the open ground (early spring and summer sowing time). As a result of repeated inbreeding, inbred lines of European winter radish (brought to the seventh generation) were created, characterized by high equalization of the root crop, with strict self-compatibility. These lines were included in the process of creating heterosis hybrids. Evaluation of the obtained hybrids was carried out in the open ground. A hybrid of radish European winter Tsyganskiy Baron F1 – medium-ripe, flat-rounded root, black, weighing 220-260 g. Perspective hybrid in relation to the standard has a more aligned form of the root, with a rich black color and smooth surface. Tsyganskiy Baron F1 on the above indicators exceeds the standard night, resistant to stressful conditions.

The effect of sowing time on the growth of chia (Salvia hispanica L.): What do nonlinear mixed models tell us about it?

Chia (Salvia hispanica L.) is an annual short-day plant whose growth has not been studied extensively in low-altitudes and at temperatures outside of its optimal range. The objective of this study was to describe the growth dynamics of a chia crop from an experimental plantation in south-east Mexico, on three different sowing dates. The chia grew at temperatures (18–37°C) and an altitude (9 m a.s.l.) outside of the recommended conditions (20–30°C, 500–1000 m a.s.l.). Three individual-plant responses were measured weekly, before seed harvest: height, number of leaves and number of inflorescences. Three theoretical nonlinear growth models were fitted to the data, a different model for each response. Mixed-effect model parameters were estimated by maximum likelihood, and the goodness of fit for each model was evaluated using two criteria: Modeling Efficiency and Root Mean Square Error. Chia seed yield was also measured in each treatment. Estimated parameters for plant height confirmed that medium sowing time (MST) and late sowing time (LST) plants had smaller heights than the early sowing time (EST) plants. Moreover, at the end of their life cycle, EST plants had a greater number of leaves and inflorescences, and higher seed yield. All of these differences were associated to the extended time of vegetative growth of EST plants favored by optimal photoperiod and temperature. Growth dynamics of chia during its ontogenic phases was explored, in more detail, with relative growth parameters derived from fitted models: a decrease in photoperiod influences the beginning of the reproductive phase, with the consequent reduction in speed of vegetative growth. In addition, nonlinear mixed-effects models can be useful in understanding the relation between growth parameters, plant maturity, and the suitable time for chia seed harvest. Our results suggest chia crops are adaptable to non-conventional environmental conditions.

Influence of Agricultural Management on Phytochemicals of Colored Corn Genotypes ( Zea mays L.). Part 2: Sowing Time.

Among the agronomic practices carried out in corn cultivation, the early sowing time is increasingly used by farmers of temperate regions to improve yield and reduce mycotoxin contamination of corn grains. The present study determined the influence of sowing time on the phytochemical content of grains of 10 colored genotypes of corn. There was a significant improvement of both grain yield (+26%), thousand kernel weight (+3%), and test weight (+2%) in plots sown early. The early sowing also significantly influenced the chemical composition of corn grains, with an increase in the concentration of cell-wall-bound phenolic acids (+5%) and β-cryptoxanthin (+23%) and a decrease in the concentration of lutein (-18%) and total anthocyanins (-21%). Environmental conditions that occurred during grain development significantly influenced the phytochemical content of corn grain, and early spring sowing could impart advantages in terms of both productivity and content of some antioxidants of whole-meal corn flour.

Reakcja ozimych odmian lnianki siewnej (Camelina sativa (L.) Crantz) na zróżnicowany termin siewu

In the seasons 2012/2013 - 2014/2015 an experiment was conducted in the fields of the Experimental Station Variety Examination in Przeclaw. The evaluated factors were as follows: (A) - sowing time (early, optimal, delayed) and (B) – Polish winter varieties of false flax (Maczuga, Luna, Przybrodzka). The study showed that early sowing time contributed to the lengthening of the vegetation period of plants, especially in relation to delayed sowing date. During the winter, the plant losses amounted on average to 11.3 pcs.∙m-2. The highest plant density before harvest was recorded in the plots of the optimal sowing date. The early sowing time contributed to the increase in the value of SPAD (Soil Plant Analysis Development) and the number of silicles per plant as well as seed yield. Sowing the seeds in the optimal time was increased lodging while delayed caused an increase in the MTA (Mean Tip Angle) and LAI (Leaf Area Index) index and plant height as well as the number of seeds per silicle. The thousand seeds weight was 0.85 g and was not significantly modified by experimental factors. The varieties were differed in most of the studied traits, including yield seeds. The results of the research carried out indicate that in the area of the research, the best time sowing the seeds of winter false flax is the first decade of September.