The Effective Pollination Period of European Plum (Prunus domestica L.) Cultivars in Western Norway

This study evaluated the effective pollination period (EPP) in four European plum (Prunus domestica L.) cultivars (‘Mallard’, ‘Edda’, ‘Jubileum’, and ‘Reeves’) during two years (2018–2019) under the environmental conditions in western Norway. The pollination of plum cultivars was carried out one, three, five, seven, and nine days after anthesis (DAA) with a pollen mix of two compatible cultivars (‘Victoria’ and ‘Opal’). Initial, middle-season, and final fruit set was recorded after one month and two months after pollination and just before the harvest, respectively. On average from both years cultivar ‘Jubileum’ had the highest fruit set when pollinated one, three, five, seven, and nine DAA (33.23%, 30.83%, 8.47%, 3.08%, and 1.15%, respectively), which was more than two folds higher fruit set than in the other studied cultivars. Cultivar ‘Jubileum’ showed significantly reduced fruit set between pollination on five and nine DAA, while cultivars ‘Mallard’, ‘Edda’, and ‘Reeves’ had markedly reduced fruit set if pollinated three to five DAA, implying that the EPP in ‘Jubileum’ was five days while in the rest it was three days. Variation of weather conditions during the flowering period in both years did not have a major effect on the receptivity of stigmas in the studied plum cultivars, which means that the existing differences in the length of EPP is maternal-genotype dependent.

Characterization of Soluble Sugar Content, Related Enzyme Activity and Gene Expression in the Fruits of ‘Minihyang’ Mandarin on Different Rootstocks

‘Minihyang’ mandarin bears fruits with small size and high sugar content. ‘Minihyang’ mandarin grafted on trifoliate orange (TO) tends to be vigorous and develops water sprout open. It is associated with insufficient floral differentiation and fruit set. Recently, the use of Flying Dragon (FD) as rootstock with a high dwarf effect has been proposed to improve this situation. Therefore, this study was conducted to evaluate the effect of two different rootstock genotypes on tree growth, fruit yield, and fruit quality at the physiological, biochemical, and molecular levels. As a result of the study, in FD, tree vigor was stably maintained, fruit size was large, and the sugar content was high compared to the TO. Fructose, glucose, and sucrose of fruit continued to increase from development to maturity. In particular, fructose and sucrose were significantly higher in the fruits of the FD than those in TO at 150 and 220 days after anthesis. The total sugar content was also significantly higher in the fruit of the FD. The activities of SPS and SS associated with sucrose synthesis tended to be increased during the fruit maturity season, but there was no significant difference between the two rootstocks. On the other hand, the activities of SS and AI breaking down sucrose were high in FD at 150 and 220 days after anthesis. These results suggest that the unloading of sucrose might be increased and affect the sugar content. However, the results of real-time PCR analysis of gene expression related to sucrose metabolism did not show an association with changes in enzyme activity affecting sugar content. Therefore, further detailed studies on the process after the regulation of gene expression are likely to be needed.

Determining conditions for best pollen quality of red-purple tree tomato (Solanum betaceum Cav.) germplasm

The germination and viability of pollen are characteristics required for fecundation when individuals of different or the same species are crossed. For this reason, assessing these parameters in selected individuals to be used in breeding programs will increase the chances for the obtainment of new progeny. In this study, pollen from different accessions of the red-purple tree tomato (Solanum betaceum Cav.) was used: local cultivar (Morado Puntón), two commercial varieties (Large Red and Oratia Red) and six segregants [(Solanum unilobum x Solanum betaceum) x Solanum betaceum]. Three types of flowers were taken (A-day of anthesis, B-one day after anthesis, and C-two days after anthesis). The pollen was conserved in two temperatures (4° and 22° C) and four storage times (0, 5, 10, 20 days). The percentage of germination and pollen viability of the selected individuals were evaluated. It was observed that the commercial materials showed higher germination percentages than the segregants in flower A and B at a temperature of 4 ° C at all storage times, except for the segregants GT7P47 and GT7P48 at the same temperature on day 0. In addition, high percentages of viability were obtained both in flowers A and B, at both temperatures and at all storage times. However, the immediate use of pollen after it is collected is recommended because better germination is achieved. This study is helpful to improve breeding procedures in the initial stages of directed crosses.

Carbohydrate Assimilation and Translocation Regulate Grain Yield Formation in Wheat Crops (Triticum aestivum L.) under Post-Flowering Waterlogging

In a two-year field study, we quantified the impact of post-flowering soil waterlogging on carbon assimilation and grain yield formation in wheat crops. At anthesis, wheat cultivars YangMai 18 (YM18) and YanNong 19 (YN19) were waterlogged for different durations i.e., 0 (W0), 3 (W3), 6 (W6) and 9 (W9) days using artificial structures. Changes in leaf physiology, carbon assimilation and biomass production were quantified at 0, 7, 14, and 21 days after anthesis under all treatments. Short-term (W3) waterlogging had no significant effect on wheat crops but W6 and W9 significantly reduced the net photosynthetic rate (Pn), leaf SPAD value, and grain weight of the tested cultivars. Increasing waterlogging duration significantly increased dry matter accumulation in the spike- axis + glumes but reduced dry matter accumulation in grain. Further, the tested cultivars responded significantly variably to W6 and W9. Averaged across two years, YM 18 performed relatively superior to YN19 in response to long-term waterlogging. For example, at 14 days after anthesis, W9 plants of YM18 and YN19 experienced a 17.4% and 23.2% reduction in SPAD and 25.3% and 30.8% reduction in Pn, respectively, compared with their W0 plants. Consequently, YM18 suffered a relatively smaller grain yield loss (i.e., 16.0%) than YN19 (23.4%) under W9. Our study suggests that wheat cultivar YM18 could protect grain development from waterlogging injury by sustaining assimilates supplies to grain under waterlogged environments.

Plant Growth Regulators INCYDE and TD-K Underperform in Cereal Field Trials

Using plant growth regulators to alter cytokinin homeostasis with the aim of enhancing endogenous cytokinin levels has been proposed as a strategy to increase yields in wheat and barley. The plant growth regulators INCYDE and CPPU inhibit the cytokinin degrading enzyme cytokinin oxidase/dehydrogenase (CKX), while TD-K inhibits the process of senescence. We report that the application of these plant growth regulators in wheat and barley field trials failed to enhance yields, or change the components of yields. Analyses of the endogenous cytokinin content showed a high concentration of trans-zeatin (tZ) in both wheat and barley grains at four days after anthesis, and statistically significant, but probably biologically insignificant, increases in cisZ-O-glucoside, along with small decreases in cZ riboside (cZR), dihydro Z (DHZ), and DHZR and DHZOG cytokinins, following INCYDE application to barley at anthesis. We discuss possible reasons for the lack of efficacy of the three plant growth regulators under field conditions and comment on future approaches to manipulating yield in the light of the strong homeostatic mechanisms controlling endogenous cytokinin levels.

Seed Quality as Related to Harvest Time in Three Key Perennial Grasses Native to Puna Tussock Rangelands of Peru

Seed-based rehabilitation programs represent a primary foundation for rangeland recovery, which requires high-quality seed of key native species. The objective of this research was to determine the seed quality at different harvest times for three key perennial grasses native to puna tussock rangelands of Peru: Festuca dolichophylla, Festuca humilior, and Calamagrostis vicunarum. Seeds of each species were harvested at 21, 28, and 35 days after anthesis and evaluated by standard tests to determine the purity, size, viability, and germinability. On average, the seed purity of the studied species ranged between 23% and 44%, hundred-seed weight between 34 mg and 73 mg, seed viability between 24% and 60%, and the seed germination between 18% and 34% over the harvest dates. The highest seed quality was observed in C. vicunarum. Seed quality parameters of the studied species did not show a consistent variation over the harvest times. Overall, the species studied presented relatively low seed quality; therefore, when using it in rehabilitation programs for rangeland recovery, it is important to carry out a previous cleaning process (to reduce nonviable seeds and inert matter) and to use a sufficient quantity of seed for effective establishment of these key grasses.

Fenologia da Ouratea hexasperma (A.St.-Hil.) Baill. (Ochnaceae) nos Tabuleiros Costeiros Cearenses

Estudos fenológicos são importantes na estimativa de produção para melhor aproveitamento socioeconômico de uma espécie. A Ouratea hexasperma (A.St.-Hil.) Baill. é utilizada na ornamentação, na recuperação de áreas degradadas e possui grande potencial medicinal. Desse modo, o presente trabalho objetivou caracterizar a fenologia da Ouratea hexasperma (A.St.-Hil.) Baill. nos Tabuleiros Costeiros cearenses. Na área de estudo (Jardim Botânico de São Gonçalo) foram selecionadas 10 plantas de Ouratea hexasperma (A.St.-Hil.) Baill., monitoradas entre os meses de agosto/2015 a julho/2016. Na fenologia anual verificou-se que o desfolhamento ocorreu de setembro/2015 a fevereiro/2016, o enfolhamento ocorreu durante todo o ano, a floração em outubro/2015 e a frutificação de outubro/2015 a março/2016. Na fenologia da floração a frutificação verificou-se que a espécie apresentou inicialmente 1.681 botões florais, sendo necessários 14 dias após a marcação (DAM) para que 9,2% das flores entrassem em antese e 7 dias após a antese (DAA) para ocorrer a fecundação. Os estádios chumbinho (EC), 1 (E1), 2 (E2), 3 (E3), 4 (E4) e 5 (E5) do fruto ocorrem respectivamente aos 14, 28, 42, 56, 84 e 105 DAA. Apenas 43 frutos conseguiram atingir o último estádio (E5). O mericarpo do fruto apresentou medidas 3,39-10,20 x 2,24-5,11 mm. Conclui-se que o ponto de colheita ideal dos frutos da Ouratea hexasperma (A.St.-Hil.) Baill. é no estádio 4 (E4-maduro), com uma estimativa da produção de um fruto por panícula. Phenology of Ouratea hexasperma (A.St.-Hil.) Baill. (Ochnaceae) in the Coastal Board of CearáA B S T R A C TPhenological studies are important in estimating production for better socioeconomic use of a species. The Ouratea hexasperma (A.St.-Hil.) Baill. it is used in ornamentation, in the recovery of degraded areas and has great medicinal potential. Thus, the present work aimed to characterize the phenology of Ouratea hexasperma (A.St.-Hil.) Baill. in the Coastal Board of Ceará. In the study area (Botanical Garden of São Gonçalo), 10 plants of Ouratea hexasperma (A.St.-Hil.) Baill. Were selected, monitored between August/2015 to July/2016. In annual phenology, it was found that defoliation occurred from September/2015 to February/2016, leafing occurred throughout the year, flowering in October/2015 and fruiting from October/2015 to March/2016. In the flowering phenology, fruiting showed that the species initially presented 1,681 flower buds, being necessary 14 days after marking (DAM) for 9.2% of the flowers to enter anthesis and 7 days after anthesis (DAA) to occur fertilization. The lead (SL), 1 (S1), 2 (S2), 3 (S3), 4 (S4) and 5 (S5) stages of the fruit occur at 14, 28, 42, 56, 84 and 105 DAA respectively. Only 43 fruits managed to reach the last stage (S5). The mericarp of the fruit presented measures 3.39-10.20 x 2.24-5.11 mm. It was concluded that the ideal harvest point for the fruits of Ouratea hexasperma (A.St.-Hil.) Baill. it is in stage 4 (S4-ripe), with an estimate of the production of one fruit per panicle.Keywords: Batiputá, phenophase, floral biology, plant ecophysiology, Vegetation Complex of the Coastal Zone.

Physical and chemical properties, pectinases activity, and cell wall pectin of Acidulus, Momordica, Inodorus and Cantalupensis melons with different ripening degree at harvest

The objective of the present study was to evaluate the physical and chemical changes, pectinases activity, and cell wall pectin in melon varieties Acidulus (access 16), Momordica (access 2), Inodorus (cv. ‘Iracema’) and Cantalupensis (cv. ‘Olympic’), in the relation of ripening degree at harvest. Melon fruits were planted and evaluated with different ripening degree at harvest, from 15 to 35 days after anthesis (DAA). The fruits, arranged in a completely randomized design, had been evaluated on the harvest days to physical and chemical characteristics. We evaluate pectin methylesterase, polygalacturonase, beta-galactosidase, and pectin contents (water-soluble, chelate soluble, and sodium carbonate soluble). The ideal harvest for each melon was, 35 days after anthesis for cv ‘Iracema’, 30 days after anthesis for cv. ‘Olympic’, 30 days after anthesis for access 16, and 20 days after anthesis for access 2. High pulp firmness of access 16 is associated with the high levels of sodium carbonate soluble pectin and low levels of polygalacturonase and beta-galactosidase activity. Momordica melon fruit cracking is related to the high levels of pectinases activity, as well as pectin degradation.

MicroRNAs modulate ethylene induced retrograde signal for rice endosperm starch biosynthesis by default expression of transcriptome

Control of stage specific spike in ethylene production at anthesis has been a vauable route to potentially enhance genetic ceiling for grain filling of rice spikelet. A number of genes controlling ethylene homeostasis and starch synthesis have been identified so long, but lack of credible information on master modulation of gene expression by miRNAs and their target genes associated with hormonal dynamics obfuscate mechanisms controlling genotype difference in quantum of grain filling. The confusion accounts for consequent shrinkage of options for yield manipulation. In a two by two factorial design, miRNA regulation of spikelet specific grain development in low against high sterile recombinant inbred lines of rice Oryza sativa L. namely CR 3856-62-11-3-1-1-1-1-1-1 (SR 157) and CR 3856-63-1-1-1-1-1-1-1 (SR 159) respectively, and inferior verses superior spikelets were compared during first 10 days after anthesis. Grain filling was poorer in SR159 than SR157 and inferior spikelets in the former were most vulnerable. Between the cultivars, overall expression of unique miRNAs with targets on ethylene pathway genes was higher in SR159 than SR157 and the situation was opposite for auxin pathway genes. Precision analysis in psTarget server database identified up-regulation of MIR2877 and MIR530-5p having Os11t0141000-02 and Os07t0239400-01 (PP2A regulatory subunit-like protein and ethylene-responsive small GTP-binding proteins) and MIR396h having Os01t0643300-02 (an auxin efflux carrier protein) and Os01t0643300-01 (a PIN1-like auxin transport protein), as targets with highest probability at anthesis and 5 days after anthesis respectively, in the inferior spikelet and the fold change values of DGE matched with pattern of gene expression (relative transcript level) in the qRT-PCR studies conducted for relevant miRNAs and protein factors for ethylene and auxin signalling. In conclusion, epigenetic regulation of both auxin and ethylene homeostasis control grain filling of rice spikelet was established, but evidences were more robust for the latter.

Determinação de alterações morfológicas durante a maturação de sementes de melão com uso de raios X

The search for melon with high physiologic quality is essential to have competitive material compared to the imported. The analysis of images realized through X-ray is a technique that verify internal morphology and relates with the seed performance. In this way, the goal of this study was to evaluate the seed physiological quality from melon of Anton cultivar in function of different phase of maturation of stored and non-stored fruits through the visualization of internal morphology of seeds using X-ray images. The experiment was managed from December of 2016 to February of 2018. The yellow-melon fruits analyzed were cultivated in Embrapa Hortaliças greenhouse. The fruits were picked in five distinct periods: 30, 45, 60, 75, and 90 days after anthesis (DAA). In each period were picked a total of 30 fruits where 15 fruits had their seeds immediately extracted after been picked, and 15 fruits were stored. The 15 fruits stored were packed in plastic box properly identified for a period of fifteen days in airy place with room temperature. The 30 fruits were subjected to the same process of seed extraction, washing and drying. The dried seeds from stored and non-stored fruits were submitted to the following analyses: X-ray test and the germination test. The treatment of 60 DAA over storage shown better performance with 67% in the germination test on the first counting and 87% of normal seedlings. This result is similar to the noted in the X-ray test where the treatment demonstrated 96% of filled seeds showing the viability of this tool to determine physiologic quality in the melon seeds.