Duration Of Growing Season Research Articles

Assessment of the genetic parameters of soybean genotypes for precocity and productivity in the various cultivation conditions

Soybean (Glycine max [L.] Merr) plays a crucial role in the advancement of agriculture in Kazakhstan, serving as a promising food crop and feed source. The primary challenge in boosting soybean production in Northern Kazakhstan lies in the absence of soybean cultivars suited to the region's conditions. As such, the foremost focus of breeding initiatives should be on creating soybean varieties that possess both early maturity and satisfactory yield potential. The objective of this research was to assess the impact of maturity time (MT) on both the yield formation and the adaptive characteristics of soybean varieties from different origins. This evaluation was conducted by analyzing the outcomes of their testing under diverse cultivation conditions in the northern region of Kazakhstan. The soybean cultivars that were examined, originating from various sources, were classified into three primary groups. These groups varied in terms of their growing season duration as well as their yield levels. The way the alleles of the E1–E4 flowering genes were spread out in the identified clusters showed that for soybean varieties where recessive alleles of the E1–E4 genes build up, the growing season usually shorter. Cultivars of Chinese, Russian, and domestic selections isolated as a result of the research were good initial material for use in local breeding programs. Within the framework of the clusters, an environmental assessment of soybean accessions was carried out, which made it possible to determine their degree of plasticity and, in general, their adaptive potential in the conditions of Northern Kazakhstan. The best cultivars were the Chinese selection ‘Dongnong 63’ and the Russian selection ‘SIBNIIK 315’. Hence, the present study successfully discovered soybean cultivars that possess exceptional adaptability and flexibility. These cultivars hold significant potential for cultivation and practical use in the specific environmental circumstances of northern Kazakhstan.

Ranking of spring bread wheat genotypes according to the heading date and growing season duration in different ecogeographic environments

Background. Adaptation of spring bread wheat cultivars to climate change requires a study of the factors affecting the length of their growing season in various environments. An attempt is made to analyze regularities in the effect of ecogeographic conditions on the correlations shown by the duration of the growing season and interphase periods in spring bread wheat genotypes.Materials and methods. Correlation coefficients were studied for the impact of the environment and temperature on the duration of the interphase periods from sprouting to heading (SH) and from heading to yellow ripeness (HR) versus the period from sprouting to yellow ripeness (SR) in VIR’s wheat collection across 18 sites located in Russia and Uzbekistan from 41 to 60°N and from 30 to 135°E. The effect of the genotype and year on SH and HR was studied, and agrometeorological regression models of SH and HR were constructed, based on the data obtained during the studies of the collection in St. Petersburg in 1945–2021.Results. For the sites below 52–54°N, the SR/SH correlation coefficient was generally higher than SR/HR, and in the upper latitudes it was vice versa. The change in the ratio of coefficients occurred due to an increase in the interannual variability of HR at lower temperatures. The effect of HR on SR became greater than that of SH at temperatures below 18°С during HR. The data of a long-term study in St. Petersburg demonstrated that the effect of the genotype on SH was 18.9%, with 68.9% of the year, and the effect of the factors on HR was 4.1 and 71.3%, respectively. Regression models showed that HR was determined by temperature for at least 81%, while SH had a lower coefficient of determination by weather (56%).Conclusion. Ranking of wheat genotypes according to their heading time reflected their differentiation in earliness. A significant contribution of HR was conspicuous under temperatures below 18°C after heading at latitudes above 52–54°N.

Sunflower (Heliánthus ánnuus) Yield and Yield Components for Various Agricultural Practices (Sowing Date, Seeding Rate, Fertilization) for Steppe and Dry Steppe Growing Conditions

The dynamics of the productivity of the sunflower hybrid “Baiterek 17” were studied for rainfed conditions of the steppe and dry steppe zones of Kazakhstan for two fertilizer levels (without fertilizers and with the application of a nitrogen-phosphorous fertilizer), two sowing dates, and three seeding rates. The growing season duration varied among zones and was affected by sowing dates. An increase in duration (3–5 days) was observed for the early sowing date and fertilized treatments, regardless of the zone. Increasing the seeding rate for all treatments by sowing date and fertilizer application reduced the duration of the growing season by 3–6 days. The fertilizer application did not affect the formation of seedlings in the study areas. In the dry steppe zone, from 2.5 to 4.8 plants/m2 were formed before harvesting, with an increase in the number of plants at the high seeding rate (57,000 seeds/ha). In the steppe zone, the same pattern was preserved: from 3.5 to 4.9 plants/m2 at a seeding rate of 65 thousand seeds/ha. The maximum diameter and weight of the flower head were found for the early sowing date and fertilized treatments at a low seeding rate, with a strong effect on the yield for both the steppe and dry steppe zones in 2022. On average, for both years, the highest yield for the dry steppe zone was obtained for the sowing date of 15 May and at a seeding rate of 57,000 seeds/ha, while for the steppe zone, the highest yield was obtained for the 10 May planting date and at a sowing rate of 65,000 seeds/ha. Improving plant nutrition and increasing the plant density up to a seeding rate of 65,000 seeds/ha for the early sowing dates (10 May) increased the plasticity in the steppe zone. For the dry steppe zone, the plasticity of the hybrid decreased, but the highest plasticity was also obtained for an earlier sowing date (15 May) and at a seeding rate of 57,000 seeds/ha crop. The study shows that the hybrid “Baiterek 17” has a high ecological plasticity under changing environmental conditions and, with an increase in moisture availability, it requires intensive agricultural practices (fertilization, increased seeding rate, and early sowing dates) to obtain a high yield.

Productivity and growing-season stability in common bean (Phaseolus vulgaris L.) under contrasting ecogeographic conditions

Background. Studying the effect size of the environment versus breeding-oriented plant traits is relevant under climate change. Identification of stable accessions while evaluating the source material in contrasting environments can increase the efficiency of breeding practice.Materials and methods. Thirty common bean accessions from the VIR collection were sown for 3 years in the contrasting environments of Maikop and Astrakhan. Eight useful agronomic traits were studied according to VIR’s guidelines. Statistical processing was carried out using ANOVA, correlation and regression analyses. Environmental stability of productivity was assessed according S. A. Eberhart and W. A. Russell (1966).Results and discussion. The study of the variability of traits showed the stability of the sowing-to-ripening period duration (average coefficient of variation: 10.9%) and 1000 seed weight (17.3%). The effect of the genotype was the determining factor only for 1000 seed weight (67.6% of the variance). The growing season duration, number of pods per plant, number of seeds per pod, and productivity depended more on the environments. Productivity formation patterns were basically the same at both sites: productivity of an accession depended on the number of pods, and 1000 seed weight was negatively related to the number of seeds per pod. The growing season in Maikop depended on the flowering-to-ripening period (r = 0.73); in Astrakhan, on the sprouting-to-flowering period (r = 0.85). The duration of the sowing-to-sprouting and sprouting-to-flowering periods significantly correlated with mean temperatures (r = –0.87 and 0.87, respectively), while the flowering-to-ripening period did not depend on the mean temperature.Conclusion. Accessions relatively stable in their productivity and duration of the growing season were identified. They demonstrated both determinant and indeterminate growth, attesting to the prospects of breeding work with different common bean groups.

Past and future changes in the start, end, and duration of the growing season in Poland

The aim of the study was to determine the direction and rate of the projected changes of the start, end, and duration of the growing season in Poland in two-time horizons: 2021–2050 and 2071–2100. The main part of the paper was preceded by an analysis of changes in the start and end dates and the duration of the growing season in Poland in the period 1966–2020. The growing season in Poland is projected to be the shortest in mountain areas and in the north-eastern regions of Poland, where the date of growing season start is the latest and the date of the growing season end is the earliest. Whereas the longest growing season due to the projected earliest start and latest end dates is expected in the southwestern Poland. In the case of the coast, its late end will be of the greatest importance for its duration as a result of the warming effect of the sea in the autumn–winter period. The most intensive changes are forecasted in the long-term perspective in the case of the scenario regarding a high level of greenhouse gas emissions. The forecasts show that outside mountain areas, the growing season duration will vary from less than 255 days in the northeastern regions to more than 290 days in southwest and western Poland. In the duration of the mountains, the growing season will vary from 180 days on Kasprowy Wierch to 188 days on Śnieżka. This suggests significant changes in agroclimatic conditions in Poland.

An analysis of yield dynamics in Peredovik sunflower variety in the conditions of the North Caucasus Region

The results of observations for 1971–2002 were used to analyze the long-term trends of yield and the duration of the growing season in the sunflower variety Peredovik. The regression analysis has shown that the growing season duration decreases with the increase in the sum of temperatures above 15 °C. The yield of sunflower was negatively associated with the sums of temperatures and the sums of precipitation in May–August, and positively with the precipitation in April. According to the regression analysis in differences, the main factor influencing the yield variability was the hydrothermal coefficient for the period with temperatures above 20 °C, the second factor was spring precipitation. The possible presence of a non-linear trend in yield dynamics that is not related to weather and climate conditions has been revealed. With the sustained tendency of the last 30 years towards an increase in temperatures and a decrease in precipitation in April, the growing season will keep shortening and the yield decreasing.

Frost Conditions Due to Climate Change in South-Eastern Europe via a High-Spatiotemporal-Resolution Dataset

Frost incidents comprise significant extreme weather events owing to climate change, possibly endangering the agricultural sector of the already impacted south-eastern European area. Thus, the comprehensive evaluation of the frost conditions under the climate regime for eleven countries was conducted by calculating relevant frost agroclimatic indicators under three time horizons (1985 to 2015, 2005 to 2035 and 2015 to 2045). The Frost Days (FD), Free of Frost Days (FFD), Last Spring Frost (LSF) and First Autumn Frost (FAF) were estimated daily over a grid of 25 × 25 km. We demonstrated that the FD will be reduced according to the balanced A1B emissions scenario over the entire examined area with the mountainous and continental regions being most affected. From 2005 to 2035, a higher LSF reduction is expected over Greece and Albania and the earlier FAF in high altitude areas. All examined regions are projected to face delayed FAF, from 2015 to 2045. In general, all countries will face an increase in the growing season duration owing to the increase of the FFD.

ВИЗНАЧЕННЯ ТРИВАЛОСТІ ВЕГЕТАЦІЙНОГО ПЕРІОДУ ЛІНІЙ РОЗЛУСНОЇ КУКУРУДЗИ (ZEA MAYS L. EVERTA STURT.) ЗА КЛАСИФІКАЦІЄЮ ФАО

Topicality. The of the growing season is the main breeding trait, which determines the practical use of the initial material of popcorn in a particular agroclimatic zone. Thus, so the differentiation of samples on this trait is important and relevant. Issues. Most methods for determining FAO index of popcorn lines and hybrids (Zea Mays L.) are based on the standard with a certain maturity group, while for maize (Zea Mays L. everta Sturt.) such standards are not available. Purpose. To determine the FAO index of new popcorn lines on three indicators: the number of leaves per a plant, the effective temperature sum during the growing season, and the growing season duration. Materials and Methods. The initial material was 46 popcorn lines in S5, which were developed in the Food Maize Breeding Laboratory at the Institute of Grain Crops of NAAS of Ukraine. The field trials were carried out at the Synelnykove Breeding and Research Station during 2020–2021. The FAO index of popcorn lines was determined according to Adryushchenko and Kryvytsky’s method. Results. We have determined the growing season duration of new popcorn lines according to the FAO classification by three indicators: the number of leaves per a plant, the effective temperatures sum during the growing season and the number of days until full ripening. Conclusions. It was noted that the indicator values that determine the maturity group of S5 popcorn lines can vary with growing conditions. Therefore, when only one indicator is used, we cannot obtain the accurate results. It is possible to reliably identify the maturity groups of initial material by the means of the proposed method of FAO determination on three indicators. Based on the results of the research, the new popcorn lines were divided into 3 groups. It was found that the mid-early ripening group (FAO 240-250) includes 4 lines in S5 - IKR 2-1, IKR 11-9, RV 3 and RV 1; to the mid-ripening group (FAO 320-390) – 32 lines in S5, including RR1, RR11, RS 13, RB 3, RK 43, RK 32, IKR 11-3, etc.; to the mid-late ripening group (FAO 400 - 410) - 10 lines in S5, including RV 18, RV 11, RP 61, RS 3, RV 6, etc.. It is proposed to select the lines of mid-early and mid-ripening groups for developing the new popcorn hybrids with full-value food popcorn grain. The formed working collection includes 80.4 % of samples of these maturity groups. Key words: breeding, popcorn, line, FAO maturity index, growing season, effective temperature sum.

Characterizing Seasonal Radial Growth Dynamics of Balsam Fir in a Cold Environment Using Continuous Dendrometric Data: A Case Study in a 12-Year Soil Warming Experiment

Historical temperature records reveal that the boreal forest has been subjected to a significant lengthening of the thermal growing season since the middle of the last century, and climate models predict that this lengthening will continue in the future. Nevertheless, the potential phenological response of trees to changes in growing season length remains relatively undocumented, particularly for evergreen boreal tree species growing in cold environments. Here, we used the recently defined zero growth (ZG) concept to extract and characterize the metrics of seasonal radial growth dynamics for 12 balsam fir trees subjected to a 12-year soil warming experiment using high resolution radius dendrometer measurements. The ZG concept provides an accurate determination of growth seasonality (onset, cessation, duration, growth rates, and total growth) for these slow-growing trees characterized by significant shrinkage in tree diameter due to dehydration in the winter. Our analysis revealed that, on average, growth onset starts at day 152 ± 7 (±1 SE, 31 May–1 June) and ceases at day 244 ± 27 (31 August–1 September), for a growing season duration of about 3 months (93 ± 26 days) over a 12-year period. Growing season duration is mainly determined by growth cessation, while growth onset varies little between years. A large part (80%) of the total growth occurs in the first 50 days of the growing season. Given the dynamics of growth, early growth cessation (shorter growing season) results in a higher average seasonal growth rate, meaning that longer growing seasons are not necessarily associated with greater tree growth. Soil warming induces earlier growth cessation, but increases the mean tree growth rate by 18.1% and the total annual growth by 9.1%, on average, as compared to the control trees. Our results suggest that a higher soil temperature for warmed trees contributes to providing better growth conditions and higher growth rates in the early growing season, when the soil temperature is low and the soil water content is elevated because of snowmelt. Attaining a critical soil temperature earlier, coupled with lower soil water content, may have contributed to the earlier growth cessation and shorter growing season of warmed trees.

Influence of crops mineral nutrition on the biometric indicators of grain sorghum formation

The study of the elements of grain sorghum cultivation technology, in particular, the application of mineral fertilizers, is one of the main promising tasks, which will contribute to the formation of high crop productivity. The article shows the results of studies on the effect of various doses of mineral fertilizers on the the growing season duration, feld germination and biometric indicators of sorghum plants of grain varieties Dniprovsky 39 and Vinets in the Right-Bank Forest-Steppe of Ukraine. The studies were carried out in 2016–2020 in the conditions of the Bila Tserkva Experimental Breeding Station of the Institute of Bioenergy Crops and Sugar Beet of the National Academy of Sciences – the zone of the Right-Bank Forest-Steppe of Ukraine. It was found that the use of fertilizers at a dose of N30P30K30 and N60P60K60 increased the duration of the growing season of grain sorghum plants by 1–2 days compared to the control, and at a dose of N90P90K90 and N120P120K120 by 2–3. At the calculated dose of fertilizers, the growing season was the shortest and amounted to 114 days for the Dniprovsky variety 39 and 112 days for the Vinets variety. The greatest influence on the feld germination of seeds in the years of research was exerted by weather conditions – 27.1 % and fertilizers – 13.2 %, and the degree of influence of varieties was much less 9.5 %. The results of the correlation-regression analysis reveal a strong relationship between the stem diameter and plant height, as well as between the leaf surface area and plant height. It was found out that with the application of maximum doses of fertilizers (N90P90K90 and N120P120K120) and the estimated (N50P40K70) received the maximum growth and development of plants, so it is advisable to apply the estimated dose of fertilizers below the planned yield, which will reduce production costs. Key words: varieties, fertilizers, feld similarity, plant height, leaf area.

Obtaining the initial material for soybean breeding by physical mutagenesis

Relevance. Breeding of new highly productive, adaptive, technological soybean (Glycine max L.) cultivars plays an important role in increasing the fund of food protein. In this case, the key role belongs to the initial material. However the main problem of modern breeding has become a decrease in the genetic diversity of initial material of cultivated plants, including soybean. One of the ways to increase genetic polymorphism is the usage of induced mutagenesis. X-ray radiation is a highly effective physical mutagen that is successfully used in mutation breeding to increase the productivity of cultivated plants and acquire new traits by them. In this regard, the purpose of our work was to create a new initial material for soybean selection using ionizing radiation. The experiments were carried out in 2018–2020. The study materials were soybean cultivars SibNIIK 315, Milyausha, Chera 1, Samer 3, El’dorado, Zolotistaya.Methods. For induced mutagenesis, the air-dry seeds of the cultivars El’dorado and Zolotistaya distinguished in our studies by high productivity were exposed to X-ray radiation in doses of 105, 107, 1010 rad. After irradiation, the seeds were sown in the field. Field assessments, phenological observations were carried out according to the methodology of the State cultivar testing of agricultural crops.Results. The El’dorado cultivar showed less radiosensitivity. The largest number of mutant forms was obtained from it at the maximum dose of irradiation of seeds. The mutants were grouped according to their growing season duration and productivity. The group of highly productive early ripening mutant forms is of the greatest value for soybean breeding. Mutants MR-20/19, MR-22/19, MR-24/19, MR-28/19, MR-29/19 are 9–10% more productive than the original El’dorado cultivar and can be directly used to create new cultivars. Mutant forms from other groups identified by us are also of interest for soybean breeding.

SEASONAL RHYTHMS OF PLANT DEVELOPMENT OF GLEBIONIS CORONARIA (L.) CASS. EX SPACH. IN THE CENTRAL POLISSIA AREA OF UKRAINE

The aim of our research was to study seasonal rhythms of development of Glebionis coronaria (L.) Cass. ex Spach. (garland chrysanthemum) introduced in the Central Polissia area of Ukraine, depending on abiotic conditions of the plant environment. The study of phenology of introduced plants was carried out from 2013 till 2017 in the Botanical Garden of Polissia National University. We calculated the effective heat sum above 5°C, required for a certain phase of development and for the plants life cycle in general. It was established that under conditions of Central Polissia in Ukraine during the period of 2013–2017 G. coronaria vegetated for 102–132 days at the effective heat sum of 1471.4–1780.3°C. Seedlings appeared between late April and early May at a rather wide range of effective heat sums, i.e. from 131.4°C to 195.2°C. The vegetative phase lasted 35–41 days, until early June. The budding phase began in early June at the effective heat sum of 351.5–502°C and lasted until late June, i.e. for 20–24 days. The beginning of the flowering phase was recorded between mid and late June with a wide range of the effective heat sums of 527°C–755.3°C. The duration of the phase varied significantly over the years of research: from 41 to 60 days. The fruiting phase occurred in late June – mid July at the effective heat sum of 780,5–1074,2оС і and lasted from 28 to 52 days. The phase of fading began in late July – mid August at the effective heat sum of 1116.5°C–1464.2°C. Vegetation ended between early August and early September. The timings of phenological phases that reflect seasonal development depend largely on temperature and water supply. The biological needs of the introduced plants for the growing season duration and thermal regime fully correspond to the natural conditions of the Central Polissia area of Ukraine, which confirms that cultivation of G. coronaria in this region is highly promising.

DYNAMIC PARAMETERS OF PRODUCTIONAL PROCESS OF EARLY RIPENING SOYBEAN VARIETIES DEPENDING ON MOISTURE CONDITIONS OF THE VEGETATION PERIOD

Due to change of temperature and moisture regime and the shift of the isotherm of the sum of active temperatures from north to south in the Central region of Non-Black Soil zone, it became possible to expand the areas occupied by soybean crops and introduce new crops to more northern regions. In this regard, it became necessary to analyze the change of dynamic parameters of development of early-ripening soybean varieties of different origin - the northern ecotype, southern and Far Eastern ones in the conditions of the Central region of the Non-lack Soil zone with sufficient moisture supply as well as arid conditions during the growing season. The studied soybean varieties had differences in the growing season duration and the sum of active temperatures. The growing season of varieties of the northern ecotype was 85–100 days, the sum of active temperatures was 1700–1900°C; as for the southern ones: 90–105 days and 1900–2200°C; and the Far Eastern varieties: 95–105 days and 2000–2300°C. The maximum dry biomass averaged 5400–5700 kg/ha under conditions of favorable hydrothermal regime of the growing season, and did not exceed 3400 kg/ha under dry conditions. It was found that in case of sufficient moisture supply (HTC = 1–1.5), the southern varieties are more consistent with the possible variability of thermal resources in the Central region of the Non-Black Soil zone in terms of development than the Far Eastern ones and, along with the varieties of the northern ecotype, can be recommended for cultivation in the region. As far as arid conditions (HTC < 1) is concerned, no fundamental differences between the groups of varieties in terms of production process characteristics were revealed. The duration of the growing season correlated with the temperature and moisture regime of the growing season. The growing season was reduced by 5–8 days on average for varieties in dry years (HTC < 1), in wet years (HTC > 1.6) it increased by 6–10 days.

INFLUENCE OF SOWING TIME AND FERTILIZER DOSAGE ON WEEDINESS AND YIELD OF SWEET SORGHUM

The studies were carried out in order to determine the appropriate period of sowing and doses of mineral fertilizers for sweet sorghum in 2018-2020 on leached medium-thick, heavy loamy black soil of Zakamie of the Republic of Tatarstan. Humus content was 6.0-6.2% (according to Tyurin), alkaline hydrolysable nitrogen - 81-84 mg/kg, mobile forms of phosphorus - 167-170 mg, exchangeable potassium - 172-173 mg/kg of soil (according to Chirikov); the sum of the absorbed bases is 40.3-40.8 mg-eq per 100 g of soil, hydrolytic acidity - 3.42-3.50, pH of the salt extract - 5.6-5.7. The seeding amount was 300,000 pcs/ha of viable seeds, the depth of seed placement was 5–6 cm. Mineral fertilizers were applied after harvesting the previous crop, before main tillage. The main tillage type was 22 - 24 cm depth plowing. The forecrop was annual grasses for haylage. High weediness was observed in sorghum crops of the first term (10 May). Moreover, the doses of applied fertilizers significantly increased the weed infestation, their number was 58 pcs/m2on an unfertilized background in the full shoots phase, whereas, their number was 69 pcs/m2 on the background of N60P60K60, and 76 pcs/m2 on the background of N80P80K80. The above trend persisted throughout the growing season of the agrophytocenosis. The sowing time and the mineral nutrition background influenced both the growing season duration and crop formation: N60P60K60, the duration of the growing season averaged 113 days over three years, which is 9 days more compared to the control. The variant of the mineral background up to N80P80K80 increased the vegetation period by 15 days compared to the unfertilized variant of the experiment. The mineral nutrition background of N60P60K60 in the second term of sorghum sowing allowed to obtain a yield increase of feed mass from 6.6 to 8.0 t/ha. The application of mineral fertilizers at a dose of N80P80K80 provided a yield increase from 10.8 to 15.4 t/ha.

Stand Biomass at Treeline Ecotone in Russian Subarctic Mountains Is Primarily Related to Species Composition but Its Dynamics Driven by Improvement of Climatic Conditions

Climate change effects are strongest in forest ecosystems at the limit of their distributions. Despite the evidence that treelines have shifted upwards by hundreds of meters, knowledge of the associated changes in the stand biomass is limited. In this study, stand biomass and changes to it during the last centuries were estimated along 20 altitudinal transects reaching from the historical (located in the 1950s–1960s) closed forest line up to the current treelines on mountain slopes of three subarctic regions of Russia (Kola Peninsula, Polar Urals, and Putorana Plateau) along a 2200 km long longitudinal gradient. The estimates were based on allometric measurements of 139 trees of five species (Betula pubescens Ehrh. ssp. tortuosa, Pinus sylvestris L., Picea abies Ledeb. ssp. obovata, Larix sibirica Ledeb., and Larix gmelinii Rupr.), stand structure assessments, and the demographic patterns of 9300 trees. During the 20th century, the growth and establishment of trees at the forest–mountain tundra transition (340–500 m width) increased exponentially. Since 1910 forest expansion and densification led to an accumulation of 621–748 tons of aboveground stand biomass per km of treeline length. The accumulation was two times higher below than above the contemporary closed forest line. Data analysis of weather stations showed that the 20th century’s climate had changed in a similar manner in the three study regions, namely vegetation periods became longer (8–10 days) and warmer (0.6–0.9 °C) and more snow fell in the cold period (+10–30%). Our results indicate that regional patterns in stand biomass at the treeline ecotone are primarily related to tree species composition as determined by macroclimatic conditions (e.g., continentality, sunshine hours), snowpack depth, and growing season duration. However, the stand biomass accumulation was driven by increases of early summer temperatures and early winter precipitation during the last century.

МАТЕМАТИЧНА МОДЕЛЬ ПРОДУКТИВНОСТІ СОРГО ЗЕРНОВОГО НА ПІВДНІ УКРАЇНИ ЗАЛЕЖНО ВІД УМОВ ЗВОЛОЖЕННЯ ТА СОРТУ

The article contains the results of mathematical modeling of grain sorghum yield in the South of Ukraine under different input parameters of wetting and growing season duration.

Harnessing phenological traits of wild ancestor Chenopodium hircinum to improve climate adaptation of quinoa

Context Cultivation of quinoa (Chenopodium quinoa Willd.) is rapidly expanding worldwide. Characterisation of populations of Chenopodium hircinum Schard., its wild ancestor, which thrives in some of the hottest environments in South America, may provide adaptations to new environments. Aims This study evaluated the developmental patterns of populations of C. hircinum collected from a range of agroecological environments in Argentina, in order to quantify variability among sites of origin and to explore the association between climatic data from environments of provenance and variation in development. Methods Thirty-three populations of C. hircinum from contrasting sites of origin in Argentina were multiplied in a common-garden experiment under non-limiting conditions of water and nutrient availability. Plants were sampled once or twice weekly (according to parameter) for estimation of the duration of developmental phases, leaf number, and dates of initiation of branching on the main stem. Key results Significant variation was detected for all phenological traits, and populations were categorised into six groups based on similarity of patterns of variation. We found positive association of the duration of development phases and the number of leaves on the main-stem with maximum temperature during the growing season, and negative association with altitude of origin, consistent with variation in growing-season duration. Conclusions The finding that late-flowering populations are associated with warmest climates reveals that longer vegetative growth is an adaptive strategy to cope with heat stress in Chenopodium spp. Implications Time to flowering should be considered in attempts to improve quinoa performance under heat-stress conditions. Further work is needed to understand the genetic basis controlling this response in wild populations of C. hircinum.

Influence of climatic indicators on the dynamics of the growing season duration and forecasting vegetable peas’ harvest date

The aim of the study was to determine the variability of climatic factors, to assess their influence on the yield and the duration of interfacial periods of vegetable pea varieties. The experiment was carried out from 2000 to 2019. 4 varieties with shrunken seeds of different ripening groups were studied. For interfacial periods, the sum of effective temperatures above 4.4 °C (ET), the sum of heat units from 4.4 °C (HU), the sum of active temperatures above 10 °C (SAT), the sum of precipitation (SP), the hydrothermal coefficient (HTC), the number of days with temperatures above 30 °C (T>30 ° C), with precipitation from 1 to 20 mm/day (1<P, mm<20) and with precipitation over 20 mm/day (P, mm>20) were calculated. In the south of Russia, the yield of vegetable peas is limited by precipitation frequency (from 1 mm to 20) on the days from sowing to technical ripeness. The studied parameters of environmental conditions characterizing the provision of moisture (HTC, SP, 1<P, mm<20, P, mm>20) and the number of days with T>30°C have a high level of variability. The number of days from sowing to sprouting and SAT of the “sprouting-technical ripeness” period are stable traits recommended for predicting the harvesting date of vegetable peas. A significant reduction in the growing season and its components was established in varieties of medium and late ripening when comparing modern (2000-2019) and earlier data (1964-1990). The results obtained indicate climatic changes, in connection with which it becomes necessary to use earlier varieties in production.

УСЛОВИЯ ВЕГЕТАЦИИ И ПРОДОЛЖИТЕЛЬНОСТЬ МЕЖФАЗНЫХ ПЕРИОДОВ ВЕГЕТАЦИИ ЯРОВОЙ МЯГКОЙ ПШЕНИЦЫ В ЗАСУШЛИВЫХ УСЛОВИЯХ

The research was carried out on southern carbonate black soil in the central zone of Orenburg region. The aim of the study was to study the relation between the vegetation season duration and the interphase periods of spring wheat and the air temperature regime and productivity. Rise of climate aridity as well as rise of temperature stress on the plant due to lack of precipitation leads to changes in crop phenology towards reduction of the growing season duration. The dependence of wheat yield on average daily and maximum air temperature for interphase periods was studied, their adaptive parameters were specified: for average temperature for the period from germination to earing - 10.5 ° С and 19.7 ° С for the period from earing to full ripeness. The actual data on duration of the interphase vegetation periods of spring wheat in different years on favourableness are given. Reliable correlations between the yield and the duration of the interfacial periods of the growing season are established. The variety specificity in the studied variants of the experiment is shown. As a result of the study, it was found that the relative duration of the vegetation season for spring wheat in the Orenburg Cis-Urals zone is 91 days with a yield level of 27.4 dt/ ha. A sharp (by 15 days) reduction of the growing season duration leads to a yield decrease to 2.8 dt/ ha.

Temporal Pattern Analysis of Cropland Phenology in Shandong Province of China Based on Two Long-Sequence Remote Sensing Data

Vegetation phenology dynamics have attracted worldwide attention due to its direct response to global climate change and the great influence on terrestrial carbon budgets and ecosystem productivity in the past several decades. However, most studies have focused on phenology investigation on natural vegetation, and only a few have explored phenology variation of cropland. In this study, taking the typical cropland in the Shandong province of China as the target, we analyzed the temporal pattern of the Normalized Difference Vegetation Index (NDVI) and phenology metrics (growing season start (SOS) and end (EOS)) derived from the Global Inventory Monitoring and Modeling System (GIMMS) 3-generation version 1 (1982–2015) and the Vegetation Index and Phenology (VIP) version 4 (1981–2016), and then investigated the influence of climate factors and Net Primary Production (NPP, only for EOS) on SOS/EOS. Results show a consistent seasonal profile and interannual variation trend of NDVI for the two products. Annual average NDVI has significantly increased since 1980s, and hugely augmentations of NDVI were detected from March to June for both NDVI products (p &lt; 0.01), which indicates a consistent greening tendency of the study region. SOSs from both products are correlated well with the ground-observed wheat elongation and spike date and have significantly advanced since the 1980s, with almost the same changing rate (0.65/0.64 days yr-1, p &lt; 0.01). EOS also exhibits an earlier but weak advancing trend. Due to the significant advance of SOS, the growing season duration has significantly lengthened. Spring precipitation has a relatively stronger influence on SOS than temperature and shortwave radiation, while a greater correlation coefficient was diagnosed between EOS and autumn temperature/shortwave radiation than precipitation/NDVI. Autumn NPP exhibits a nonlinear effect on EOS, which is first earlier and then later with the increase of autumn NPP. Overall, we highlight the similar capacity of the two NDVI products in characterizing the temporal patterns of cropland phenology.