Onset Of Phenological Phases Research Articles

Peculiarities of the phenological phases of the development of pear varieties in the conditions of the steppe zone of the Southern Urals

The article presents the results of long-term studies of the peculiarities of the phenological phases of the development of promising pear varieties of domestic breeding in the conditions of the steppe zone of the Southern Urals (Orenburg region). The research was carried out in 2018-2021 at the experimental site of the 2002 laying of the Orenburg branch of the Federal Research Center of Horticulture. The objects of research were varieties of pears of domestic breeding Krasnobokaya (st), Skazochnaya, Pingvin, Permyachka, Sverdlovchanka, Isetskaya sochnaya, Lel, Chizhovskaya, Lada, Vidnaya, Povislaya (st), Gvidon, Uralochka, Samarskaya krasavitsa, Pamyat of Parshin. The calculation of phenological atypicity to identify the correspondence of the phases of development of pear varieties to the conditions of the region was carried out according to the method of Zaitsev G. N. Statistical processing of the obtained data was carried out in accordance with the methodological recommendations of Zaitsev G. N. and Dospekhov B. A. using the Microsoft Office Excel 10 analysis package. It was established that the studied varieties are characterized by a short growing season — 160-170 days; the required amount of active heat is on average 3 158.9 °C. For pear varieties, the timing of the onset of phenological phases is determined by the accumulated sum of positive temperatures: the beginning of vegetation — 200-304.7 °C; the beginning of flowering – 354-476.6 °C; removable fruit maturity — 2 504-3 603 °C; the end of leaf fall — 3 1793-666 °C. It was found that the timing of the onset of the phenological phases of the beginning of vegetation, the beginning and end of flowering, the end of shoot growth, as well as the duration of flowering periods, shoot growth and vegetation depend more on the conditions of the year than on the genotype. The removable maturity of fruits, the duration of the interphase period, the formation and growth of fruits are determined by characteristics of the variety. The assessment of phenological atypicity revealed that all the studied varieties are in the optimum for the realization of their phenological phases of development.

Resistance of generative organs of sweet cherry to spring frosts after artificial freezing

Aim.The purpose of this research was to study the sustainability of Institute bred sweet cherry cultivars to spring frosts during flowering by the method of artificial freezing and to identify resistant cultivars.Material and Methods. Seven Institute bred sweet cherry cultivars were studied: 'Adelina', "Malysh", "Orlovskaya Rozovaya", "Orlovskaya Feya", "Podarok Orlu", "Siyana" and "Trosnyanskaya". Spring frosts were simulated in an "Espec" PSL-2KPH climate chamber in early May at -1°, -2°, -3° and -4°C. At each temperature regime, 100 pcs of flowers and buds of each cultivar were taken in 3-fold repetition. Temperature was lowered at the rate of 1°C per hour. The duration of exposure to negative temperatures was 3 hours.Results.Damage to the stamens and pistils was assessed by the darkening of the tissues. In buds and blooming flowers after frosts, the pistils were first damaged but the stamens were not. Resistance to spring frosts decreased with the phenological development of the cherry's generative organs. The beginning of damage to the flowers as a result of the artificial freezing was noted at a temperature of -1°C. At the same time, the high stability of cherry buds was noted. Modeling frosts of -2°...-4°C increased the number of dead flowers and buds. The resistance of sweet cherries to spring frosts was found to depend on the genotype and stage of development of reproductive organs. A different sum of active temperatures for the beginning of flowering and ovary formation was noted, indicating the onset of phenological phases in which generative organs are susceptible to spring frosts.Conclusion.The experiment made it possible to distinguish a medium-resistant cultivar "Malysh" which was resistant to spring frosts. Weakly stable genotypes were "Orlovskaya Rozovaya", "Orlovskaya Feya", "Trosnyanskaya" and "Siyana". Unstable cultivars were "Adelina", and "Podarok Orlu". During the formation of the ovary, the greatest potential for resistance to spring frosts was shown by "Podarok Orlu".

Climate factors influence on biological features of Crataegus maximowiczii C.K. Schneid. when introduced within the arctic circle

This study evaluates the development of Crataegus maximowiczii when introduced to the Kola Peninsula. The paper presents the timing of the onset of phenological phases, morphometric indicators of inflorescences and flowers, fruits, features of seed reproduction. C. maximowiczii is a plant with an early onset and short growing season. C. maximowiczii has a short shoot growth period, a short prefloral period, annual flowering and fruiting. The studied specimens of C. maximowiczii plants were characterized by heterogeneous morphometric parameters of flowers and inflorescences. Specimens with a denser inflorescence are characterized by a greater number of flowers per inflorescence, specimens with small flower sizes form medium-sized inflorescences. The species specificity factor affects the morphometric characteristics of inflorescences. Fruiting indicators largely depended on external conditions, among which temperature and relative humidity of the air have little effect. Plants of C. maximowiczii, when introduced to the Kola Peninsula, can be classified as small-fruited. The highest germination capacity is possessed by the samples with average values of mass, which have undergone combined pre-sowing preparation. The relative humidity of the air during the growing season has a greater effect than the temperature regime on the values of the mass of seeds for a given species under conditions of introduction.

Vplyv prízemnej vegetácie a podrastu na priebeh fenologickej krivky bukových porastov odvodenej z údajov MODIS / Effect of understory vegetation and undergrowth on course of phenological curve of beech forests derived from MODIS

Vegetation index NDVI derived from satellite data MODIS (product MOD09) was used for monitoring of phenological phases of beech stands. The effect of leaves of upper story and undergrowth trees, understory vegetation, bark of thin and thick branches, trunk, and litter on NDVI value was identified and quantified for determination of the onset of phenological phases in five beech stands. The phenological observations were carried out in the spring 2011. Phenological curves were modelled for each stand. Inputs were NDVIsat derived from MODIS. The NDVI value for each component was determined from spectral analyses, and its percentage was estimated. Consequently, NDVIₘₒdₑₗ values were calculated for each stand and compared with NDVIₛₐₜ. We found out that NDVIₛₐₜ values are systematically biased from NDVIₘₒdₑₗ values a quotient q was established to revise this biased NDVIₛₐₜ values. Possibilities for satellite long-term phenological monitoring resulted from the quantified effect of individual forest components on NDVI value. The 100% leaf onset is the most suitable phase for phenological monitoring of the canopy trees component. The 100% leaf budburst is suitable phenophase for monitoring of forest stands phenology.

Phenology of four broad-leaved forest trees in a submountain beech forest

The phenology of four deciduous forest tree species (<I>Carpinus betulus</I> L., <I>Fagus sylvatica</I> L., <I>Quercus dalechampii</I> Ten., <I>Tilia cordata</I> Mill.) was studied in a submountain beech forest stand in Central Slovakia. Two spring phenological phases – bud-burst and leaf unfolding as well as one autumn phase – autumn leaf colouring were monitored over the period of 13 years. The results documented interannual variability in the dating of phenological phases within the species, while the differences among the species were also revealed. Significant correlations (<I>P</I> < 0.05) were detected between the dating of leaf unfolding and air temperature; the coefficients of correlation (<I>r</I>) ranged from –0.86 (hornbeam and beech) to –0.92 (oak). Significant relationships were also revealed between cumulative precipitation amounts and timing of autumn leaf colouring phase (<I>r</I>-value ranged from –0.73 in oak to –0.81 in hornbeam). The trend analysis showed that the onset of phenological phases was slightly shifted to the earlier dates during the period of 13 years. However, the trends were not statistically significant.

Satellite‐based mapping of the growing season and bioclimatic zones in Fennoscandia

ABSTRACTAim To test whether satellite‐derived NDVI values obtained during the growing season as delimited by the onset of phenological phases can be used to map bioclimatically a large region such as Fennoscandia.Location Fennoscandia north of about 58° N and neighbouring parts of NW Russia.Methods Phenology data on birch from 15 research stations and the half‐monthly GIMMS‐NDVI data set with 8 × 8 km2 resolution from the period 1982–2002 were used to characterize the growing season. To link surface phenology with NDVI data, new algorithms on a pixel‐by‐pixel basis that show high correlation with phenophases on birch were developed. Then, time‐integrated values (TI NDVI) during the phenologically defined growing season were computed to produce a bioclimatological map of Fennoscandia, which was tested and correlated with growing degree days (GDD) obtained from 20 meteorological stations. The map was also compared vs. traditional bioclimatic maps, and analysed for error factors distorting NDVI values.Results The correlation between GDD and TI NDVI data during the phenologically defined growing season was very high. Therefore, the TI NDVI map could be presented as a bioclimatic map reflecting GDD. However, several major areas have interfering factors distorting NDVI values, such as the pixel heterogeneity caused by the altitudinal mosaic in western Norway, the mosaic of lakes in southeastern Finland, and the agriculture‐dominated areas in southern Fennoscandia.Main conclusions TI NDVI data from the phenologically defined growing season during 1982–2002 in Fennoscandia can be processed as a bioclimatic map reflecting GDD, except for the areas distorting NDVI values by their strong ground‐cover heterogeneity.