Evaluation of Phenological and Agronomical Traits of Different Almond Grafting Combinations under Testing in Central Italy

In the new introducing almond areas, it is necessary to test the more promising almond cultivar and rootstock combinations able to guarantee the best agronomic performances according to the specific pedoclimatic conditions. With this aim, two almond trials have been established in an experimental farm located in the Latium region (Italy). The first trial (A) focused on the phenological, and agronomical influences induced by the clonal rootstock ‘GF677’ on the grafted cultivars ‘Tuono’, ‘Supernova’ and ‘Genco’, in comparison to those induced by peach seedling rootstocks, in order to identify the best grafting combination for developing “high density” plantings in this new growing area. The second trial (B) tested the phenological and agronomical influences induced by three different clonal rootstocks (‘GF677’, ‘Rootpac® 20’ and ‘Rootpac® R’), on the Spanish cultivar ‘Guara’ to identify suitable dwarfing rootstocks for “super high density” plantings in the same environment. Flowering and ripening calendars of the trial A highlighted as the medium-late flowering cultivars ‘Genco’, ‘Supernova’ and ‘Tuono’ could be subject to moderate risk of cold damages. The clonal rootstock ‘GF677’ seems to anticipate flowering and vegetative bud break by a few days in ‘Tuono’ when compared to the same cultivar grafted on peach seedling rootstocks. Furthermore, the yield per plant was always higher in plants grafted on ‘GF677’. The observations carried out in trial B highlighted as the flowering of cultivar ‘Guara’ were affected by the rootstock, with ‘Rootpac® 20’, which postponed its full bloom of about one week when compared to other rootstocks, whereas ‘GF677’ imposed more vigor to the cultivar than ‘Rootpac® 20’ and ‘Rootpac® R’.

Climate Change Impacts on Plant Phenology: Grapevine (Vitis vinifera) Bud Break in Wintertime in Southern Italy

The effects of global warming on plants are not limited to the exacerbation of summer stresses; they could also induce dormancy dysfunctions. In January 2020, a bud break was observed in an old poly-varietal vineyard. Meteorological data elaboration of the 1951–2020 period confirmed the general climatic warming of the area and highlighted the particular high temperatures of the last winter. Phenological records appeared to be significantly correlated to wood hydration and starch reserve consumption, demonstrating a systemic response of the plant to the warm conditions. The eight cultivars, identified by single-nucleotide polymorphism (SNP) profiles and ampelographic description, grown in this vineyard showed different behaviors. Among them, the neglected Sprino, Baresana, Bianco Palmento, and Uva Gerusalemme, as well as the interspecific hybrid Seyve Villard 12.375, appeared to be the most interesting. Among the adaptation strategies to climate changes, the cultivar selection should be considered a priority, as it reduces the inputs required for the plant management over the entire life cycle of the vineyard. Hot Mediterranean areas, such as Salento, are a battlefront against the climate change impacts, and, thus, they represent a precious source of biodiversity for viticulture.

Impact of Foliar-Applied Dormancy-Breaking Chemicals on Budburst and Metabolic Changes in Chemical Constituents of Leaves and Fruits of Malus sylvestris "Ein Shamer"

This study was carried out during the two successive seasons of 2016 and 2017 to investigate the impact of dormex, dormex plus mineral oil, dormex plus potassium nitrate, dormex plus calcium nitrate and dormex plus thiourea on bud break, growth, yield and some chemical constituents of Malus sylvestris "Ein Shamer". The trees were grown in loamy sand soil, and sprayed with six treatments (dormex (4%), (dormex (2%) plus mineral oil (2.5%),(dormex (2%) plus potassium nitrate (4%),(dormex (2%) plus calcium nitrate (4%) and (dormex (2%) plus thiourea (1%) and control. Generally, it was found that all studied growth parameters , date of flower bud break, percentage of bud break, fruit-setting ,fruit weight, fruit size, fruit number/tree, yield/tree (kg) and some chemical constituents of leaves (total chlorophyll ,total carbohydrates, total protein, nitrogen, phosphorous and potassium contents) and some chemical constituents of fruits (total soluble solids(T.S.S.), T.S.S/ acid ratio, vitamin C, water content %, total free amino acids, total carbohydrates, total sugars and reducing sugars) were increased with the application of the different treatments. The best results were obtained from the treatments of dormex at 4% followed by (dormex (2%) plus mineral oil (2.5%). On the contrary, the same treatments decreased total acidity and total phenols in fruits as compared to the control. It could be recommended to use dormex at 4% and (dormex (2%) plus mineral oil (2.5%) for improving bud break, growth, yield and chemical constituents of apple trees or fruits.

Atmospheric Warming-Associated Phenological Earliness Does Not Increase the Length of Growing Season in Himalayan Trees

We present phenological data for two time periods (1985–1987 and 2014–2016) on major tree species (Shorea robusta, Pinus roxburghii, Myrica esculenta, Quercus leucotrichophora, Rhododendron arboreum, Quercus floribunda, and Machilus duthiei) occurring along an altitudinal gradient of 300–2,200 m asl of Himalayan forests (a data-deficient region identified by the IPCC, 2007), and show that bud break and leafing in trees has advanced at 0.20 days/year, which is associated with a significant (P < 0.001) increase in atmospheric temperature (0.038°C/year) over the years in the study area. Also, the leaf drop period has advanced correspondingly (0.40 days/year); hence, the length of season (LOS) did not increase in these trees. This finding is contrary to the report of increase in LOS due to climatic warming from temperate latitudes of the world and satellite-based studies in Himalayan region. Arguably, phenomena such as bud break and leafing may not be captured by remote sensing, which is critical for determining the impact of climate change on the forest vegetation of the eco-sensitive Himalayan region. We suggest that this phenological earliness may alter forest structure and functioning and associated ecosystem services of these forests in the long run. Study Implications: This study suggests that bud break and leafing in trees has advanced, an advancement that is associated with the significant increase in atmospheric temperature over the years in the study area. However, the leaf drop period has advanced correspondingly; hence, the length of season of trees in the study area did not increase. Nonetheless, the earliness in the leafing and leaf drop have potential implications on forest ecosystem structure and functioning, such as photosynthesis, carbon assimilation, increased asynchrony in plant-pollinators and animal interactions, reproduction success, and herbivory that require further detailed investigation. Warming may also advance seed maturation and desiccation of seeds that may disrupt the synchrony between monsoon and tree seed germination, forest regeneration, and ensuing ecosystem services. Generalizations on a regional scale on the impact of climate change on annual patterns of growth of forests that are based on remote-sensing studies could mask the impact of the premonsoon period, when bud break and leafing take place. These impacts may not be captured by remote sensing; impacts which, in this study, we have found to be critical.

Estimation of Chilling Accumulation for Blackberry (Rubus sp.) Using Mathematical Models

As the climate change takes place, the cultivation of temperate climate crops in subtropical areas has become a challenge. The success of fruit crops, such as blackberry, in certain areas depends basically on its chilling requirement and the chilling accumulation in those areas. Usually the models used to predict those accumulations presents widely variable results being necessary to test the models in the location where the species is cultivated. The objective of this work was to estimate the chilling requirement for bud break of blackberry cultivars Caingangue, BRS Cainguá, Guarani, Tupy, BRS Xavante, BRS Xingu, Brazos, Cherokee and Choctaw, using the models of Utah, Positive Utah, Low Chill, Taiwan, Chilling Hours ≤7.2°C, Chilling Hours ≤11°C, and Dynamic and both temperature and phenological data from 2010 to 2019. The results showed a high variability in cold accumulation for all studied cultivars in all tested models. None of the models performed perfectly to estimate chilling requirement however, the Taiwan and the Utah Positive models can be used to provide a rough estimate of this requirement. On the other hand, Utah and Low Chill models are clearly not suitable for estimating blackberry chilling requirement. The estimated chilling requirement showed that all the studied cultivars are well adapted to the climatic conditions of the southern Rio Grande do Sul, which is emphasized by their good productivity in most of the years.

Endodormancy Release Can Be Modulated by the GA4-GID1c-DELLA2 Module in Peach Leaf Buds

Gibberellin (GA) plays a key role in the release of bud dormancy and the GA receptor GID1 (GIBBERELLIN INSENSITIVE DWARF1) and DELLA protein are the GA signaling parts, but the molecular mechanism of GA-GID1-DELLA module regulating leaf bud dormancy in peach (Prunus persica) is still not very clear. In this study, we isolated and characterized the GID1 gene PpGID1c from the peach cultivar “Zhong you No.4.” Overexpressing PpGID1c in Arabidopsis promoted seed germination, which indicated that PpGID1c has an important function in dormancy. The expression level of PpGID1c in peach leaf buds during endodormancy release was higher than that during ecodormancy and was positively correlated with GA4 levels. Our study also found that GA4 had the most obvious effect on promoting the bud break, indicating that GA4 may be the key gibberellin to promoting peach leaf bud endodormancy release. Moreover, a quantitative real-time PCR (qRT-PCR) found that GA4 could increase the expression of the gibberellin signaling gene PpDELLA2. A yeast two-hybrid (Y2H) assay suggested that the PpGID1c interaction with the PpDELLA1 protein was not dependent on gibberellin, while the PpGID1c interaction with PpDELLA2 required GA4 or another gibberellin. These findings suggested that the GA4-GID1c-DELLA2 module regulates peach leaf bud endodormancy release, with this finding significantly enhancing our comprehensive understanding of bud endodormancy release and revealing a new mechanism for regulating leaf bud endodormancy release in peach.

Precipitation before Flowering Determined Effectiveness of Leaf Removal Timing and Irrigation on Wine Composition of Merlot Grapevine

Grapevine productivity, and berry and wine flavonoid concentration, depend on the interactions of cultivar, environment, and applied cultural practices. We characterized the effects that mechanical leaf removal and irrigation treatments had on the flavonoid concentration of ‘Merlot’ (Vitis vinifera, L.) grape berries and wines in a hot climate over two growing seasons with contrasting precipitation patterns. Leaves were removed by machine, either at prebloom (PBLR), or at post-fruit-set (PFLR), or not removed (control) and irrigation was either applied as sustained deficit irrigation (SDI) at 0.8 of crop evapotranspiration (ETc) from budbreak to fruit set, or regulated deficit irrigation (RDI) at 0.8 ETc from bud break to fruit set, 0.5 ETc from fruit set to veraison, and 0.8 ETc from veraison to harvest, of ETc In 2014, PFLR reduced the leaf area index (LAI) compared to control. The RDI decreased season-long leaf water potential (ΨInt) compared to SDI. However, in 2015, none of the treatments affected LAI or ΨInt. In 2014, berry flavonoid concentrations were reduced by PBLR as well as SDI. SDI increased the flavonoid concentrations in wine, and PFLR increased some wine flavonols in one season. No factor affected the concentrations of wine proanthocyanidins or mean degree of polymerization. Thus, mechanical PFLR and RDI may increase berry flavonoid accumulation without yield reduction, in red wine grapes cultivars grown in hot climates when precipitation after bud break is lacking. However, spring precipitation may influence the effectiveness of these practices as evidenced by this work in a changing climate.

Thidiazuron with Mineral Oil as Alternative Bud Break Promoter for Apple Trees

Aims: This work aims to evaluate the efficiency of Revent® 500 SC (Thidiazuron) concentrations as a bud breaker promoter in apple trees, cv. Maxi Gala and Supreme Fuji, through phenology, sprouting of buds, fruit set and production per plant. Place and Duration of Study: The experiments were carried out in southern Brazil, municipality of Caçador / SC, during the seasons from 2017 to 2019, in the cultivars Fuji Suprema and Maxi Gala / Marubakaido / M9. Methodology: The treatments were 1. Control (without application); 2. Mineral Oil (MO) 3.5% + Hydrogenated Cyanamide (HC) 0.35%; 3. MO 3.5% + HC 0.5%; 4. MO 3.5% + Thidiazuron (TDZ) 0.005%; 5. MO 3.5% + TDZ 0.01%; 6. MO 3.5% + TDZ 0.015%; 7.MO 3.5% + TDZ 0.02%; 8.MO 3.5% + TDZ 0.025%, applied in stages B and C. Several variables were evaluated such as phenology, sprouting of axillary and terminal buds, fruit set, production per plant and average fruit mass. Results: All treatments with bud breakers advanced the phenological stages in relation to the control in the three years. In the sprouting of the axillary and terminal buds, all treatments were superior to the control. TDZ treatments showed higher sprouting of axillary buds in 2017/18 compared to standard treatments with hydrogenated cyanamide. In plant production, the treatment MO 3.5% + TDZ 0.02% was higher than the other treatments in the 2018/19 and 2019/20 seasons, in both cultivars. TDZ associated with mineral oil is efficient in inducing the sprouting of ‘Maxi Gala’ and ‘Fuji Suprema’ apple trees and can be used to recover sprouts from previous years.

Drought Analysis During the Growth Stages of Grape in the Main Grape-Growing Regions in China

In China, grape is one of the top five fruit crops for both bearing acreage and production. Recently, national grape production has been stalling because of an increase in drought events. In order to combat the adverse effects of drought on grape production, it is imperative to understand the historical drought trend and frequency during the growing season. In this study, we focused on agricultural drought during the four growth periods of grape: bud break-flowering, flowering-veraison, veraison-berry maturation, and berry maturation-leaf fall. Based on the weather data from 429 meteorological stations, we computed the Crop Water Deficit Index (CWDI) in the five main grape-growing regions of China: Northeast China, North China, Northwest China, Southwest China, and Southeast China. Then we evaluated the CWDI-based drought distribution and trend in the study regions, as well as the frequency of different degrees of drought. The results showed that exceptional drought was occurring frequently in Xinjiang Uyghur Autonomous Region, northern Gansu province, and northern Ningxia Hui Autonomous Region. Among the four study growth periods of grape, exceptional drought was the most expansive during bud break-flowering. What’s more, exceptional drought coverage during bud break-flowering in the study regions was increasing from 1981 to 2016. Analysis of butterfly structure showed that the occurrence of drought was continuous and persistent in northern China. Our study results could serve as guideposts to highlight Chinese grape production industry’s vulnerability to agricultural drought against the background of climate change.

Assessment of In-vitro culture through Nodal explants of Dendrocalamus hamiltonii

The present experimental study was aimed to overcome the traditional methods of propagation that limit the number of propagules by in-vitro regeneration through nodal explants of Dendrocalamus hamiltonii with a comparative study of growth regulators during the shooting and rooting process. Dendrocalamus hamiltonii is distributed from the Himalayas (Nepal) to the northern part of Burma. Collection of explants was done from different selected sites of CPTs. There was the use of HgCl2 and Ca (OCl)2 as sterilizing agents in different concentrations and its effect was visualized during the sprouting stage. Culm explants were cultured in a bottle containing White media (Wm) supplemented with BA and Kinetin for sprouting and IAA, IBA, NAA for rooting. There is also the use of IAA+IBA+NAA in combined form as a supplementary solution 0.1% HgCl2 treatment for 20-minute results into77.80% aseptic buds and 72% bud -break. Among the used growth-hormones, BA with concentration 0.25mg/l and 0.50mg/l respectively were appropriate for shoot-multiplication rate, 4.01±0.3 and 4.3±0.4 were ideal observation incorporation with BA (1.00mg/l) and BA (1.50mg/l) respectively. Maximum sprouting rate14.77±3.37with application of BA (2.00mg/l) and maximum shoot length4.3±0.4 is observed at BA (1.50mg/l). The applications of rooting hormone IAA+IBA+NAA in the concentration of 1.0 mg/l results in 72.5±0.3(rooting) and 11.1±0.3 (av. No. of the root).