Date Of First Flowering Research Articles

Detection of QTLs controlling flowering in a cross-pollinated F1 population of Miscanthus sinensis

Miscanthus is a perennial rhizomatous grass belonging to Andropogoneae, which is now used as lignocellulosic biomass crop. Miscanthus has a short history of domestication, so further breeding effort for improved biomass production is needed. Flowering plays a critical role in controlling vegetative growth and physiology of plant, so this study focused on finding quantitative trait locus controlling flowering of Miscanthus for use in marker assisted breeding. A cross-pollinated M. sinensis F1 population consisted of 278 progenies was produced, transplanted to the field and assessed in their flowering traits. Julian dates of flag leaf extension, first heading, half heading, first flowering, and half flowering were assessed in 2019, the third year after transplanting when Miscanthus was well established. The average Julian dates of the flowering traits were 198±9, 224±14, 233±14, 239±15 and 253±12, respectively, and showed a proximal normal distribution. Genotype by sequencing conducted by Illumina-hiseq using leaf DNA samples revealed the genetic map consisted of 1988 SNPs with average distance of 1.35 cM. Nine QTLs controlling flowering were detected exceeded 60% of LOD score threshold. These QTLs were neighboring 16 SNP markers, 5 of which were contained in known functional genes including RGL2 (gibberellin pathway regulation). Genetic map and marker information acquired through this study, including either annotated or not annotated markers, are expected to help understand and help breeding new Miscanthus in the future with desired flowering.

Biochar has positive but distinct impacts on root, shoot, and fruit production in beans, tomatoes, and willows

Positive relationships have been documented between the amount of biochar added to soils and various aspects of plant growth and fertility such as root, shoot, and fruit production. However, these effects depend on biochar source materials, soil characteristics and species of plant examined. This makes it impossible to systematically compare and generalize findings across previous studies that have used different soils and biochar. We conducted a novel investigation to assess the effects of a single source of biochar (hazelnut wood), in a constructed organic soil, on the different plant tissues in three functionally distinct species: tomatoes (Solanum lycopersicon), green beans (Phaseolus vulgaris), and willow (Salix sp.). Five levels of biochar soil amendment were assessed: 0% (control), 3, 9, and 26% by dry weight. We found a highly significant positive relationship between biochar concentration and total plant biomass (roots + shoots + fruits) in all species, with no significant difference in total biomass response among species. Fruit production increased with increased biochar in both beans and tomatoes. However, tomatoes exhibited significant differences in response among plant tissues; fruit production and shoot biomass increased significantly with biochar, but root tissue did not. Bean germination success increased significantly with biochar concentration. Date of first flowering was earlier with increasing soil biochar in beans but not in tomatoes. Control over both sources of biochar and soil composition in this experiment enables us to conclude that biochar addition can have different impacts on different plants and, in some cases, species-specific impacts on different plant tissues and other measures of fertility. Our results are contrary to prior research that found inhibiting effects of biochar at levels comparable to our 26% treatment. Biochar impacts on soil properties such as CEC and percent base cation saturation do not explain our findings, leading us to conclude that microbial interaction with biochar is an important factor that may explain the positive impacts of soil biochar on plant fertility observed. Further research that repeats this experiment in other soil types, with other biochar sources, and with other plant species is necessary to determine the generalizability of these important findings.

China's subtropical deciduous plants are more sensitive to climate change than evergreen plants by flowering phenology

AbstractThe ongoing climate change‐induced shifts in flowering phenology have emerged as a consequential force impacting biodiversity and ecosystems. Despite the globally recognized significance of flowering phenology as a key reproductive attribute, studies in subtropical regions have been relatively fewer, particularly in comparison to temperate and cold regions. Additionally, the nuanced response of deciduous and evergreen plants to climate change remains insufficiently explored. In addressing this gap, we built a phenological model and a generalized linear mixed effect model to assess the differential responses of key flowering phenological traits, that is, first flowering date (FFD), peak flowering date (PFD), end of flowering date (EFD), and flowering duration (FD), to climate factors (temperature and precipitation) between deciduous and evergreen plants. We observed distinct responses in flowering phenological traits to climate change between deciduous and evergreen plants. Specifically, the advancement of FFD, PFD, and EFD in deciduous in response to temperature rise exceeded that in evergreen plants. FD in evergreen plants exhibited a stronger extension to temperature increase compared to deciduous. Conversely, the phenological change of evergreen plants in response to decreasing precipitation was greater than that of deciduous ones. Since temperature is a decisive climatic factor in affecting phenological changes, climate change‐induced advances in flowering phenology of deciduous plants are still larger than evergreen plants. Projections from our phenological model under future climate scenarios (SSP 1‐2.6 and SSP 5‐8.5) indicate a continuous enlargement of difference in flowering phenology between deciduous and evergreen plants, with this trend escalating into the future (2100>2070>2050>2030). The larger extension in FD of evergreens to climate change suggests a potential increase in their proportion within subtropical forest communities relative to deciduous plants. These insights contribute significantly to our understanding of the intricate dynamics of climate‐induced changes in subtropical plant ecosystems.

Proximate cues of flowering in a subtropical rain forest

AbstractPlants have evolved mechanisms to track seasonal variation in environmental resources, enabling them to time key life‐history events to appropriate seasons. While the proximate cues for flowering initiation are well documented in the temperate region, it is still unclear what the flowering cues are in the tropics, especially in the subtropics. Our study compared first flowering dates (FFDs) predicted by eight hypothesized proximate cues concerning photoperiod, mean and directional changes in solar irradiance and warm/cool temperature, and rainfall with flowering dates observed over 19 years of weekly monitoring for 16 species in a subtropical rain forest. We observed considerable interannual variation in the median FFDs for the study species, ranging from 21 to 101 days. The early‐spring flowering species tended to have greater interannual variation in FFDs than the summer flowering species. For 13 study species, temperature cues best explained interannual variation in FFDs. Cool temperatures in the previous fall/winter and warm temperatures in the current spring (or previous summer) might trigger the onset of flowering in these 13 species. Cues associated with photoperiod and irradiance also predicted interannual variation in FFDs with small root mean square error (<1.5 census intervals) for 12 species but generally had higher prediction errors than temperature‐related cues. Cues associated with seasonal variation in rainfall failed to predict flowering times in any species. Our results suggest that future changes in temperature may alter flowering times for most species in subtropical forests, leading to changes in ecosystem processes and biosphere feedback to the climate system.Abstract in Chinese is available with online material.

Prediction of apple first flowering date using daily land surface temperature spatio-temporal reconstruction and machine learning

The first flowering date (FFD) is a critical phenological parameter closely related to the apple yield, so the accurate prediction of the FFD is important for precise orchard production management. Existing methods to predict the FFD are mostly based on air temperature (Ta) measured at meteorological stations, but to great differences in meteorological variations and the ecological conditions, these methods cannot present the differences of FFD under complex meteorological conditions and provide spatially continuous FFD information at the level of a region. Therefore, we propose a method to predict spatially continuous apple FFD from remote sensing land surface temperature (LST) based on flowering prediction model. Firstly, the missing LST data were reconstructed by using spatio-temporal reconstruction (STR) approach developed. Next, new air temperature (NAT) data were generated by using the daily Ta estimation (DTE) model and the reconstructed LST. Finally, apple FFD was predicted by the NAT data and the apple flowering prediction model established based on random forest (RF) algorithm and the phenology sequential model, and the prediction accuracy was verified by comparison with the independently measured apple FFD. The LST reconstructed by using the STR approach has mean absolute error (MAE) ranging from 0.51 to 0.68 °C, and root mean square error (RMSE) ranging from 1.07 to 1.21 °C. The MAE between the NAT data and the High-Resolution Land Surface Data Assimilation System (HR-CLDAS) meteorological data ranges from 2.15 to 3.23 °C, and the RMSE ranges from 2.81 to 4.27 °C. In addition, the determination coefficient (R2) and RMSE between the predicted and measured FFD is 0.72 and 2.96 days, respectively. These results demonstrate that the developed method maximizes the potential of MODIS LST in predicting spatially continuous apple FFD, which is valuable for flower and fruit thinning, to defend against frost disasters, and in general for refined orchard production management.

Spatial heterogeneity of first flowering date in Beijing's main urban area and its response to urban thermal environment.

Phenology - the rhythm of periodic plant life cycle events - was significantly shaped by urban climate, with flowering as one most sensitive phenophase. Apart from the widely noticed urban-rural phenological discrepancy caused by heat island effect, driven by the aggravating spatial unevenness of urban thermal environment, the spatial heterogeneity of flowering time was also found within the urbanized area of some metropolitans, bringing multiple impacts on urban ecology, landscape and public health. This research aimed to reveal the intraurban spatial variation and response characteristics of Beijing's trees flowering phenology that remained largely unclear before. We analyzed the spatial heterogeneity pattern of the first flowering date (FFD) for 42 deciduous woody species in Beijing's main urban area (MUA), and explored the species-specific phenological response to local thermal environment. The sample plots were set in 9 green spaces distributing from urban center to northwest suburb in Beijing's MUA, the FFD data was collected by ground-based phenological observation, and local thermal environment was measured with land surface temperature (LST) retrieved from MOD11A1 products. The main results are as follows: (1) A significant spatial variation for FFD existed among 9 sample plots and the maximum spatial difference of FFD reached 6.76 ± 1.77days in average, FFD showed an overall delay trend from urban center in 2nd Ring to outskirts beyond 5th Ring with 3rd Ring as a critical line for significant phenological difference. (2) The FFD of 35 species was found to be negatively correlated with [Formula: see text] (average of daily mean LST above 0°C before mean FFD) in the sample plot (p < 0.05) with a response sensitivity of 2.99 ± 0.87days/°C, which reflected the significant impact of LST variation during flower development period. Furthermore, the spatial difference and response sensitivity of FFD for a specific species were found to be negatively associated with its mean FFD value (p < 0.05), i.e., the flowering time of early-blooming species tended to be more sensitive to thermal environment variation compared with late-blooming ones. This research illustrated how flowering phenology responded to the heterogeneous intraurban thermal environment in Beijing's MUA, which can improve our understanding of the vegetation dynamics in a constantly changing urban environment. And as a critical indicator of trees' climate vulnerability assessment, the species-specific phenological response sensitivity could also guide species selection in urban forest construction.

Flowering time advances since the 1970s in a sagebrush steppe community: Implications for management and restoration.

Climate change is widely known to affect plant phenology, but little is known about how these impacts manifest in the widespread sagebrush ecosystem of the Western United States, which supports a number of wildlife species of concern. Shifts in plant phenology can trigger consequences for the plants themselves as well as the communities of consumers that depend upon them. We assembled historical observations of first-flowering dates for 51 species collected in the 1970s and 1980s in a montane sagebrush community in the Greater Yellowstone Ecosystem and compared these to contemporary phenological observations targeting the same species and locations (2016-2019). We also assembled regional climate data (average spring temperature, day of spring snowmelt, and growing degree days) and tested the relationship between first-flowering time and these variables for each species. We observed the largest change in phenology in early-spring flowers, which, as a group, bloomed on average 17 days earlier, and as much as 36 days earlier, in the contemporary data set. Mid-summer flowers bloomed on average 10 days earlier, nonnative species 15 days earlier, and berry-producing shrubs 5 days earlier, while late summer flowering plants did not shift. The greatest correlates of early-spring and mid-summer flowering were average spring temperature and day of snowmelt, which was 21 days earlier, on average, in 2016-2019 relative to the 1973-1978 observations. The shifts in flowering phenology that we observed could indicate developing asynchronies or novel synchronies of these plant resources and wildlife species of conservation concern, including Greater Sage-grouse, whose nesting success is tied to availability of spring forbs; grizzly bears, which rely heavily on berries for their fall diet; and pollinators. This underscores the importance of maintaining a diverse portfolio of native plants in terms of species composition, genetics, phenological responsiveness to climatic cues, and ecological importance to key wildlife and pollinator species. Redundancy within ecological niches may also be important considering that species roles in the community may shift as climate change affects them differently. These considerations are particularly relevant to restoration and habitat-enhancement projects in sagebrush communities across western North America.

Spatiotemporal Variation of Osmanthus fragrans Phenology in China in Response to Climate Change From 1973 to 1996.

Climate change greatly affects spring and autumn plant phenology around the world consequently, and significantly impacts ecosystem function and the social economy. However, autumn plant phenology, especially autumn flowering phenology, has not been studied so far. In this study, we examined the spatiotemporal pattern of Osmanthus fragrans phenology, including both leaf phenology (the date of bud-bust, BBD; first leaf unfolding, FLD; and 50% of leaf unfolding, 50 LD) and flowering phenology (the date of first flowering, FFD; peak of flowering, PFD; and end of flowering, EFD). Stepwise multiple linear regressions were employed to analyze the relationships between phenophases and climatic factors in the long term phenological data collected by the Chinese Phenological Observation Network from 1973 to 1996. The results showed that spring leaf phenophases and autumn flowering phenophases were strongly affected by latitude. BBD, FLD, and 50LD of O. fragrans were delayed by 3.98, 3.93, and 4.40 days as per degree of latitude increased, while FFD, PFD and EFD in O. fragrans advanced 3.11, 3.26, and 2.99 days, respectively. During the entire study period, BBD was significantly delayed across the region, whereas no significant trends were observed either in FLD or 50LD. Notably, all flowering phenophases of O. fragrans were delayed. Both leaf and flowering phenophases negatively correlated with growing degree-days (GDD) and cold degree-days (CDD), respectively. BBD and FLD were negatively correlated with total annual precipitation. In addition to the effects of climate on autumn flowering phenology, we found that earlier spring leaf phenophases led to delayed autumn flowering phenophases. Our results suggest that future climate change and global warming might delay the phenological sequence of O. fragrans. Our findings also advanced the flowering mechanism study of autumn flowering plants, and facilitated the accurate prediction of future phenology and climate change.

Host-mediated effects on the reproductive phenological asynchrony of a generalist mistletoe in China

AbstractHost-mediated effects on hemiparasitic mistletoes were hypothesized to contribute to mistletoes reproductive phenological asynchrony, thus providing a longer period of food supply to its mutualistic pollinators and dispersers. However, studies with empirical data interrogating this hypothesis are lacking. Weekly monitoring of flowering and fruiting patterns on a generalist mistletoe Dendrophthoe pentandra (Loranthaceae) was conducted for two consecutive years in tropical Xishuangbanna, Southwest China. We examined whether flowering and fruiting patterns were seasonal, quantified the degree of stagger within D. pentandra populations and determined the factors influencing the first flowering date (FFD) of D. pentandra. Furthermore, the effect of change in the number of host species on reproductive phenological asynchrony of mistletoe was examined. We found that (i) both flowering and fruiting exhibited unimodal peaks in the two consecutive years of the study; (ii) the FFD was significantly influenced by crown area of mistletoe and light, such that clump with larger crown and more light exposure had an earlier FFD and longer flowering and fruiting durations; (iii) different host species had a significant impact on the phenology of mistletoes. However, contrary to our hypothesis, the number of host species did not significantly change the asynchrony of reproductive phenology of mistletoe. Therefore, these results suggest that alternative hypotheses are needed to interpret the ecological significance of the number of host species and phenological asynchrony of generalist mistletoes.

Trends in Flowering Phenology of Herbaceous Plants and Its Response to Precipitation and Snow Cover on the Qinghai—Tibetan Plateau from 1983 to 2017

Based on limited controlled experiments, both advanced and delayed shifts in flowering phenology induced by precipitation and snow cover have been reported on the Qinghai–Tibetan Plateau (QTP). To clarify the impact of precipitation and snow cover on flowering phenology, we conducted a comprehensive statistical analysis of the temporal change in flowering phenology and its responses to precipitation and snow cover changes using regression models built on the largest collection of ground phenological observation data on the QTP. We found that first flowering date (FFD) for the early-flowering time series significantly advanced at the rate of −0.371 ± 0.149 days/year (p &lt; 0.001), whereas FFD mid-to-late-flowering time series showed no trend at the rate of 0.158 ± 0.193 days/year (p = 0.108). Cumulative pre-season precipitation regressed with FFD positively for early-flowering time series, with the explained variation ranging from 11.7 to 49.4% over different pre-season periods. The negative impact of precipitation on flowering phenology is unexpected, because an increase in precipitation should not hamper plant growth in the semi-arid and arid environments on the QTP. However, precipitation was found to be inversely correlated with temperature. Thus, it is likely that temperature, and not precipitation, regulated flowering phenology over the study period. No relationship was found between FFD and snow-cover melt date or duration. This result indicated that snow cover may not affect flowering phenology significantly, which may be because plant flowering time was much later than the snow-cover melt date on the QTP. These findings contrast the results of controlled experiments on the QTP, which showed that precipitation regulated flowering phenology, and with other studies that showed that snow-cover melting time determined flowering dates of early-flowering species in high latitude and Arctic zones in Europe and North America, where the low-temperature environment is similar to the QTP. These findings can improve flowering phenology models, assist in the prediction of phenological responses of herbaceous plants to climate change, and forecast changes in the structure and function of the grassland ecosystem on the QTP.

Divergent shifts in flowering phenology of herbaceous plants on the warming Qinghai–Tibetan plateau

Both advanced and delayed shifts of different magnitude in flowering phenology, based on limited controlled experiments and ground-based observational studies, have been reported on the Qinghai–Tibetan Plateau (QTP). To clarify flowering phenological changes, we collected 1646 ground-observed phenological records of 21 species, from 27 stations, for 78 time series, and daily average air temperature data from 1983 to 2017 on the QTP. Trends in the first flowering date (FFD) and changes with temperature increase were analyzed using regression models. The FFD of early flowering time series showed an overall trend for significant advance (-0.371 ± 0.149 days/year, p < 0.001), whereas the mid-to-late-flowering showed a delayed trend (0.158 ± 0.193 days/year, p = 0.108). This finding is in contrast with the stable trend for early flowering species and the advanced trend for midsummer and late-flowering species in high latitude and Arctic regions, where the low-temperature environment is similar. The growing degree days from 1 January to the day of the observed occurrence of the FFD for early flowering time series kept stable (p = 0.531) and FFD showed a positive regression with chilling days; however, the growing degree days of mid-to-late-flowering time series increased significantly at a rate of 5.375 ± 2.519°C-days/year (p < 0.001), indicating the limitation on FFD from other related climatic factors except for forcing temperature may strengthen, and FFD showed no relationship with chilling days. The mid-to-late-flowering time series showed vernalization sensitivity in the spring of the flowering year, whereas the early flowering time series did not. This indicated that retarded vernalization completion may be responsible for the delayed flowering phenology of mid-to-late-flowering species. The FFD of early flowering species, with flower preformation in the preceding autumn, was mainly controlled by forcing temperature in spring; decreased chilling days indicating warmer winter were also beneficial for development and fitness of preformed floral organs, and thus, temperature increase significantly advanced the FFD. These findings suggest that divergent flowering phenology shifts may alter the species composition and ecosystem services of alpine ecosystems, causing challenges in grassland management.

Effect of Different Cladding Material and Mulching on the Growth and Yield of Cucumber (Cucumis sativus) under Forced Ventilated Greenhouse System

The experiment was conducted at Agricultural Engineering College &amp; Research Institute, Kumulur, (TNAU), Tamil Nadu with the objectives to test the performance of different cladding (blue and white colour polyethylene) and plastic mulches (silver on black colour) on the growth and yield of cucumber (Cucumis sativus L., Fadia F1, hybrid) to find the suitable cultivation practices for obtaining higher yields in semi-arid regions.&#x0D; The observations of micro climatic parameters such as temperature, relative humidity, solar radiation, light intensity and soil temperature were recorded in each polyhouse and at control (open cultivation). The plant growth parameters like plant height, number of leaves per plant, number of branches, date of first flowering, number of fruits, individual fruit weight and leaf- area were recorded among all the treatments.&#x0D; Among the blue and white polyhouse conditions, favourable solar incidental radiation and light intensity was observed in the white polyhouse as compared to blue polyhouse. Among the plastic mulch and without mulch treatments, the plastic mulch showed negative results under polyhouse cultivation where as positive results on growth and yield parameters at open condition (control). Significant differences were found among the treatments combinations of white poly house condition without mulch treatment on higher fruit size, fruit weight, number of fruits per plant, number of leaves per plant, leaf area and higher yield might be due to higher photosynthetic active radiation than blue polyhouse. The microclimatic condition recorded in blue polyhouse found to be detrimental to the pathogens under certain wave lengths and resulted in lower incidences of pest and diseases but not supported for higher yield due to low light intensity compared to white polyhouse. White polythene film as cladding material for construction of poly house and without mulching is important to achieve higher growth and yield of Cucumber under semi-arid regions.

武汉大学樱花花期长度特征及预报方法

PDF HTML阅读 XML下载 导出引用 引用提醒 武汉大学樱花花期长度特征及预报方法 DOI: 10.5846/stxb201909241996 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划项目（2018YFA0606102） Characteristics and forecast of flowering duration of Cherry Blossoms in Wuhan University Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:武汉大学樱花是武汉的一张"城市名片"，开展樱花花期长度的预报工作，可为旅游部门管理工作和游客安排出行时间提供合理的参考。根据1979-2018年40年武汉大学樱园日本樱花树始花期和落花期的观测资料及同期气象资料的研究分析表明：（1）樱花的始花期和落花期在20世纪80-90年代期间有明显的提前；从20世纪90年代末开始至今，始花期与落花期变化趋势不明显，但变率较大，与全球气候变化停滞期相吻合；40年间花期长度变率很大，整体无明显的增多或减少的趋势。（2）平均始花期为3月14-15日，落花期为3月31日-4月1日，平均花期长度为18d。（3）花期长度与当年始花期日序数、开花期间平均气温、开花期间最高平均气温、最低平均气温和温度日较差平均值均呈负相关，与开花期间总降水量呈正相关。与开花期内平均极大风速值、平均降水量和日照时数等无明显相关性。（4）用1979-2015年共37年资料建立了樱花花期长度的单因子拟合、多因子回归及主成分分析模型，用2016-2018年3年资料进行检验，对武汉大学樱花花期长度进行了预报，取得了较好的试验效果。其中主成分回归模型、降水单因子拟合模型和多因子樱花花期长度回归模型预报效果最好，平均绝对误差在1.5d左右，后期将会把预报模型运用到实际的樱花花期预报工作中。 Abstract:Japanese cherry blossoms of Wuhan University is a city card of Wuhan. It can provide a reasonable reference for the management of tourism department and the arrangement of travel time for tourists to carry out the prediction of the length of cherry blossom period. A 40-year-old (1979-2018) dataset of flowering dates of Japanese cherry blossoms at Wuhan University Campus associated with the meteorological data was used for developing a method of forecasting the flowering duration of cherry blossoms. (1) The first-flowering and falling flowering date of cherry blossoms were obviously advanced in the 1980s-1990s. Since the end of 1990s, the trend of initial flowering and falling flower period is not obvious, but the rate of variation is large, which coincides with the stagnation period of global climate change.In the past 40 years, the change rate of florescence length was very large, but there was no obvious trend of increase or decrease. (2) The average first-flowering date was March 14-15, the falling flowering date was March 31 to April 1, and the average flowering period was 18 days. (3) The length of flowering period was negatively correlated with the first-flowering date, and negatively correlated with the average temperature, the highest average and the lowest average temperature during flowering period. It's also negatively correlated with the average daily temperature difference, and positively correlated with the total precipitation during florescence. There was no significant correlation with the average maximum wind speed, average precipitation and sunshine hours during flowering period. (4) Single factor fitting, multi-factor regression and principal component analysis model of cherry blossom period length were established based on the data from 1979 to 2015, which were tested by the data from 2016 to 2018. These models were used to predict the length of cherry blossom period in Wuhan University and good experimental results were obtained. Among them, principal component regression model, precipitation single factor fitting model, and multi-factor cherry blossom period length regression model are the best, with an average absolute error of about 1.5 days. In the future, the prediction model will be applied to the actual cherry blossom period prediction. 参考文献 相似文献 引证文献

Prediction of Plant Phenological Shift under Climate Change in South Korea

Information on the phenological shift of plants can be used to detect climate change and predict changes in the ecosystem. In this study, the changes in first flowering dates (FFDs) of the plum tree (Prunus mume), Korean forsythia (Forsythia koreana), Korean rosebay (Rhododendron mucronulatum), cherry tree (Prunus yedoensis), and peach tree (Prunus persica) in Korea during 1920–2019 were investigated. In addition, the changes in the climatic factors (temperature and precipitation) and their relationship with the FFDs were analyzed. The changes in the temperature and precipitation during the January–February–March period and the phenological shifts of all research species during 1920–2019 indicate that warm and dry spring weather advances the FFDs. Moreover, the temperature has a greater impact on this phenological shift than precipitation. Earlier flowering species are more likely to advance their FFDs than later flowering species. Hence, the temporal asynchrony among plant species will become worse with climate change. In addition, the FFDs in 2100 were predicted based on representative concentration pathway (RCP) scenarios. The difference between the predicted FFDs of the RCP 4.5 and RCP 6.0 for 2100 was significant; the effectiveness of greenhouse gas policies will presumably determine the degree of the plant phenological shift in the future. Furthermore, we presented the predicted FFDs for 2100.

Rapid Acquisition, Management, and Analysis of Spatial Maize (Zea mays L.) Phenological Data—Towards ‘Big Data’ for Agronomy Transformation in Africa

Mobile smartphones, open-source set tools, and mobile applications have provided vast opportunities for timely, accurate, and seamless data collection, aggregation, storage, and analysis of agricultural data in sub-Saharan Africa (SSA). In this paper, we advanced and demonstrated the practical use and application of a mobile smartphone-based tool, i.e., the Open Data Kit (ODK), to assemble and keep track of real-time maize (Zea mays L.) phenological data in three SSA countries. Farmers, extension agents, researchers, and other stakeholders were enlisted to participate in an initiative to demonstrate the applicability of mobile smartphone-based apps and open-source servers for rapid data collection and management. A pre-installed maize phenology data application based on the ODK architecture was provided to the participants (n = 75) for maize data collection and management over the maize growing season period in 2015–2017. The application structure was custom designed based on maize developmental stages such as planting date, date of emergence, date of first flowering, anthesis, grain filling, and maturity. Results showed that in Ethiopia, early maturing varieties took 105 days from sowing to maturity in low altitudes, whereas late-maturing varieties took up to 190 days to complete developmental stages in high altitude areas. In Tanzania, a similar trend was observed, whereas in Nigeria, most existing varieties took an average of 100 days to complete their developmental stages. Furthermore, the data showed that the durations from sowing to emergence, emergence to flowering, flowering to maturity were mainly dependent on temperature. The values of growing degree for each phase of development obtained from different planting dates were almost constant for each maize variety, which showed that temperature and planting time are the main elements affecting the rate of maize development. The data aggregation approach using the ODK and on-farm personnel improved efficiency and convenience in data collection and visualization. Our study demonstrates that this system can be used in crop management and research on many spatial scales, i.e., local, regional, and continental, with relatively high data collation accuracy.

Rootstock and Plastic Mulch Effect on Watermelon Flowering and Fruit Maturity in a Verticillium dahliae–Infested Field

Separately, grafting and the use of plastic mulch can increase yield, quality, and early harvest of watermelon (Citrullus lanatus), especially when plants are under biotic and/or abiotic stress. A 2-year field study was conducted to evaluate the combination of four different rootstocks and two types of plastic mulch (black and clear) on date of watermelon first flowering, fruit ripening, yield, and fruit quality when plants were exposed to Verticillium dahliae. Seedless watermelon cv. Secretariat was grafted onto rootstocks Lagenaria siceraria cv. Pelop, Benincasa hispida cv. Round, and two interspecific hybrid squash rootstocks Cucurbita maxima × C. moschata cvs. Super Shintosa and Tetsukabuto, with nongrafted ‘Secretariat’ as the control. Fruit were harvested 0, 7, and 14 days after both the leaflet and tendril attached to the fruit pedicel were completely dry (fruit considered to be physiologically mature). The area under the disease progress curve (AUDPC) values for verticillium wilt were not different for mulch type in either year, although the overall AUDPC value was greatly reduced in the four grafted treatments (227) compared with nongrafted (743). There was no difference in days to male or female flowering due to mulch type or year, and rootstock did not affect first flowering of male flowers. Female flowering was 14 and 11 days later in 2018 and 2019, respectively, for ‘Secretariat’ grafted onto bottle gourd ‘Round’ compared with ‘Secretariat’ grafted onto ‘Tetsukabuto’. Female flowering of ‘Secretariat’ on ‘Round’ was also 7 days later compared with nongrafted ‘Secretariat’ both years. However, days to first harvest was not different with mulch or rootstock and was 92 days after transplanting (DAT) in 2018 and 114 DAT in 2019. There was no difference in yield (fruit number and weight) due to year, harvest date, or mulch, but there was a difference due to grafting. ‘Secretariat’ grafted onto ‘Super Shintosa’ had the greatest total number and weight of fruit per plant (3.7 and 14.8 kg, respectively), and nongrafted ‘Secretariat’ had the lowest (0.7 and 3.2 kg, respectively). Fruit quality attributes hollow heart formation (rating 3.2/5 on average), hard seed count (6 on average), total soluble solids (11% on average), and lycopene content were not different among mulch type, rootstock treatment, or harvest date; however, lycopene content did differ due to year (52.44 and 32.51 µg·g−1 in 2018 and 2019, respectively). Flesh firmness was highest for watermelon grafted onto ‘Super Shintosa’ rootstock (6.7 N) and lowest for nongrafted watermelon (4.3 N). Overall, rootstocks reduced verticillium wilt severity and increased fruit yield whereas mulch had no effects, and 5 V. dahliae colony forming units (cfu)/g of soil may be the minimum level for impact on watermelon fruit yield.

The Interactive Effects of Chilling, Photoperiod, and Forcing Temperature on Flowering Phenology of Temperate Woody Plants.

The effects of winter chilling, spring forcing temperature, and photoperiod on spring phenology are well known for many European and North American species, but the environmental cues that regulate the spring phenology of East Asian species have not yet been thoroughly investigated. Here, we conducted a growth chamber experiment to test the effects of chilling (controlled by different lengths of exposure to natural chilling conditions), forcing temperature (12, 15, or 18°C) and photoperiod (14 or 10 h) on first flowering date (FFD) of six woody species (three shrubs and three trees) native to East Asia. The three-way analysis of variance (ANOVA) separately for each species showed that the effects of chilling and forcing temperature were significant for almost all species (P < 0.05). Averaged over all chilling and photoperiod treatments, the number of days until FFD decreased by 2.3–36.1 days when the forcing temperature increased by 3°C. More chilling days reduced the time to FFD by 0.7–26 days, when averaged over forcing and photoperiod treatments. A longer photoperiod could advance the FFD by 1.0–5.6 days, on average, but its effect was only significant for two species (including one tree and one shrub). The effects of forcing temperature and photoperiod interacted with chilling for half of the studied species, being stronger in the low chilling than high chilling treatment. These results could be explained by the theory and model of growing degree-days (GDD). Increased exposure to chilling coupled to a longer photoperiod reduced the GDD requirement for FFD, especially when plants grew under low chilling conditions. However, shrubs (except Viburnum dilatatum) had lower chilling and heat requirements than trees, suggesting that, by leafing out sooner, they engage in a more opportunistic life strategy to maximize their growing season, especially before canopy closure from trees' foliage. Our results confirmed the varying effects of these three cues on the flowering phenology of woody species native to East Asia. In future climate change scenarios, spring warming is likely to advance the spring phenology of those woody species, although the reduced chilling and shorter photoperiod may partly offset this spring warming effect.

Does Coltsfoot (Tussilago farfara L.) have an autumn temperature control to limit precocious flowering in spring?

AbstractThe flowering phenology of Coltsfoot (Tussilago farfara L.) shows a very strong negative response to warmer temperatures in spring (warmer springs = earlier flowering) as reported in numerous studies for other species in Europe and North America. However, despite this, flowering dates in some locations have failed to show a strong advance and, in a small number of cases, have even shown significant delays. Here we use a very extensive data set on first flowering dates (FFD) of Coltsfoot in Germany, firstly on a national scale in the period 1894–2015 and secondly at a regional level in the more thoroughly recorded period from 1951–2015. FFDs were coupled with gridded temperature data using regression techniques to attempt to understand the reasons for the unexpected changes in phenology. National mean FFD did not change significantly over 122 years, although January–March mean temperatures had warmed by 1.2°C. The flowering‐temperature model was significantly improved when the previous September mean temperature was included, which decreased the overall temperature response from 4.5 to 3.7 days/°C. For the more thoroughly recorded period of 1951–2015, January–March mean temperature warmed significantly by 1.7–2.4°C in all 11 German federal state combinations and mean FFD dates advanced by 3–14 days, significant for seven of the States. For 10 of the 11 States, multiple linear regressions explained 79–89% of the observed variation in FFD and evidenced a positive relationship (significant in half of these) with higher temperature in the September preceding flowering (warmer September = later flowering). However, the scale of the September influence is insufficient to explain why Coltsfoot flowering may have stalled or been delayed. The use of controlled experiments to supplement observational data may be necessary to fully understand the drivers of Coltsfoot flowering in spring.

Impacts of climate change on flowering phenology and production in alpine plants: The importance of end of flowering

Changes in the seasonal timing of plant flowering are hypothesized to alter the number of flowers plants produce, which contributes to reproductive success. However, empirical evidence linking specific aspects of plant flowering phenology to the number of flowers produced is limited, particularly under future global climate change. We used phenology measurements after 2, 3, 6, and 7 years of a fully factorial, climate change field experiment in an alpine meadow pasture on the central Tibetan Plateau to understand: 1) how experimental warming and snow addition affect the date of first and last flowering in related forb and shrub species, Potentilla saundersiana Royle and Potentilla fruticosa L.; and 2) how these changes in the timing of phenological events alter flowering duration and production, as a proxy for reproductive effort. We found that warming significantly advanced the date of first flowering in both P. fruticosa and P. saundersiana, with no other significant effects on flowering duration or production. In contrast to warming, simulated snowstorms delayed the date of first flowering in P. saundersiana, but had no significant effect on P. fruticosa. There were no significant treatment interactions. For both species, flower production increased as the last date of flowering occurred later. These results indicate that as climate change alters alpine plant phenology, advances in the timing of first flowering alone will not necessarily translate to increases in flowering duration and enhanced reproductive effort. Instead, these findings demonstrate the importance of the date of last flowering in mediating plant reproductive effort and success.

Phenology as a process rather than an event: from individual reaction norms to community metrics

AbstractMeasures of the seasonal timing of biological events are key to addressing questions about how phenology evolves, modifies species interactions, and mediates biological responses to climate change. Phenology is often characterized in terms of discrete events, such as a date of first flowering or arrival of first migrants. We discuss how phenological events that are typically measured at the population or species level arise from distributions of phenological events across seasons, and from norms of reaction of these phenological events across environments. We argue that individual variation in phenological distributions and reaction norms has important implications for how we should collect, analyze, and interpret phenological information. Regarding phenology as a reaction norm rather than one year's specific values implies that selection acts on the phenologies that an individual expresses over its lifetime. To understand how climate change is likely to influence phenology, we need to consider not only plastic responses along the reaction norm but changes in the reaction norm itself. We show that when individuals vary in their reaction norms, correlations between reaction norm elevation and slope make first events particularly poor estimators of population sensitivity to climate change, and variation in slopes can obscure the pattern of selection on phenology. We also show that knowing the shape of the distribution of phenological events across the season is important for predicting biologically important phenological mismatches with climate change. Last, because phenological events are parts of a continuous developmental process, we suggest that the approach of measuring phenology by recording developmental stages of individuals in a population at a single point in time should be used more widely. We conclude that failure to account for phenological distributions and reaction norms may lead to overinterpretation of metrics based on single events, such as commonly recorded first event dates, and may confound meta‐analyses that use a range of metrics. Rather than prescribing a single universal approach to studying phenology, we point out limitations of inferences based on single metrics and encourage work that considers the multivariate nature of phenology and more tightly links data collection and analyses with biological hypotheses.