Determining the Optimum Night Length for Flower Development in a Modern Poinsettia Cultivar

The effect of night length (NL) on the flower development of poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch) ‘Prestige Red’ was evaluated. Flower initiation occurred by subjecting plants to a 14-hour NL for 10 or 17 days, termed short-day (SD) treatments, and then transferring the plants to each of four NL treatments (11, 12, 13, or 14 hours) to observe the effects of NL on flower development. The plants grown continuously with the 14-h NL treatment were the control group. The timing of first color, visible bud, and anthesis were recorded during flower development, and bract and leaf data were collected at anthesis. Leaf number was unaffected by the SD or NL treatments, suggesting that flower initiation occurred during the 10-day SD treatment before the start of NL treatments; thus, the NL treatments only affected flower development. The timing of first color and visible bud were significantly delayed with the 10-day SD × 11-hour NL treatment relative to the 14-hour NL control; however, first color and visible bud were not delayed with the 17-day SD × 11-hour NL treatment. The 11-hour NL treatment resulted in fewer plants reaching anthesis, and these plants had fewer stem bracts and less bract color development compared with the 12-hour, 13-hour, and 14-hour NL treatments. Therefore, an 11-hour NL is suboptimal for flower development; nonetheless, significant development did occur. The 12-hour NL resulted in less color development than the 13-hour and 14-hour NL treatments in the lowest stem bract positions, but the plants had a commercially acceptable appearance. These results demonstrate that minimal differences in flower development occur with NL ≥12 hours, but that optimal development required NL ≥13 hours.

Screening of Onion (Allium cepa L.) Genotypes for Waterlogging Tolerance

Onion production is severely affected by waterlogging conditions, which are created due to heavy rainfall. Hence, the identification of waterlogging-tolerant onion genotypes is crucial for increasing onion production. In the present study, 100 distinct onion genotypes were screened for waterlogging tolerance under artificial conditions by using the phenotypic approach in the monsoon season of 2017. Based on plant survival and recovery and changes in bulb weight, we identified 19 tolerant, 27 intermediate tolerant, and 54 highly sensitive onion genotypes. The tolerant genotypes exhibited higher plant survival and better recovery and bulb size, whereas sensitive genotypes exhibited higher plant mortality, poor recovery, and small bulb size under waterlogging conditions. Furthermore, a subset of 12 contrasting genotypes was selected for field trials during monsoon seasons 2018 and 2019. Results revealed that considerable variation in the morphological, physiological, and yield characteristics were observed across the genotypes under stress conditions. Waterlogging-tolerant genotypes, namely, Acc. 1666, Acc. 1622, W-355, W-208, KH-M-2, and RGP-5, exhibited higher plant height, leaf number, leaf area, leaf length, chlorophyll content, membrane stability index (MSI), pyruvic acid, antioxidant content, and bulb yield than sensitive genotypes under stress conditions. Furthermore, the principal component analysis biplot revealed a strong association of leaf number, leaf area, chlorophyll content, MSI, and bulb yield with tolerant genotypes under stress conditions. The study indicates that the waterlogging-tolerant onion genotypes with promising stress-adaptive traits can be used in plant breeding programs for developing waterlogging-tolerant onion varieties.

Effects of irrigation intervals and foliar application of amino acids and humic acid on the physiological traits of strawberries under colored shading nets

BACKGROUND: The strawberry is an important commercial crop, the improvement of its yield and quality is an imperative task. OBJECTIVE: The present research aimed to study the effect of colored netting and foliar application of amino acids on the physiological characteristics of strawberries subjected to different irrigation intervals. METHODS: The study was carried out as a factorial experiment based on a randomized complete block design with three factors including colored net at 4 levels (no netting, green, red, and yellow netting), organic acids at 4 levels (control, humic acid, glutamine, and arginine), and three levels of irrigation intervals (2, 4, and 6 days) in the greenhouse of Lahijan Agricultural Research Station, Iran. RESULTS: The results showed that the highest leaf number, shoot weight, chlorophyll and carotenoid content were related to yellow netting. The highest fruit yield, anthocyanins, and flavonoids were observed in the treatments of no-netting, green netting, and red netting, respectively. Data for the effect of organic acids showed that the glutamine-treated plants exhibited the highest yield, the humic acid-treated plants displayed the highest anthocyanin and carotenoid content, and the arginine-treated plants demonstrated the highest vitamin C content. The irrigation interval of 6 days caused to the lowest leaf number, flower and fruit number, shoot weight, fruit yield, and carotenoid content. Data for the trilateral effect of ‘netting×organic acid×irrigation’ showed that the highest flower number and fruit yield were obtained from ‘green netting×glutamine×4 days’, the highest anthocyanin content was obtained from ‘green netting×humic acid×2 days’, and the highest chlorophyll content was obtained from ‘green netting×control×6 days’. The treatment of ‘yellow netting×control×2 days’ was related to the highest flavonoid content. CONCLUSIONS: The application of colored nets provides the strawberry with more optimal vegetative and reproductive growth.

Spearmint (Mentha spicata) Cultivation in Decoupled Aquaponics with Three Hydro-Components (Grow Pipes, Raft, Gravel) and African Catfish (Clarias gariepinus) Production in Northern Germany

Mint (Mentha spicata) was cultivated in different hydroponic components: grow pipes, a raft and an ebb-and-flood gravel substrate system irrigated with aquaculture effluents from intensive African catfish (Clarias gariepinus) production under decoupled aquaponic conditions in northern Germany. The spearmint grew well and plant heights above ground were not significantly different between the gravel (57.7 ± 13.1 cm), raft (58.0 ± 17.7 cm) and grow pipe components (63.6 ± 9.9 cm). Root lengths and root fresh weights were two-fold and four-fold higher in raft (64.3 ± 20.5 cm; 42.8 ± 29.9 g) and grow pipes (59.4 ± 15.2 cm; 41.3 ± 25.7 g) compared with gravel substrate (29.7 ± 7.8 cm; 9.4 ± 9.4 g; raft = grow pipes > gravel). Spearmint leaf number was significantly higher in the grow pipes (770.0 ± 224.4) than in the gravel substrate (499.8 ± 228.4) with intermediate values in the raft. Significantly highest mean fresh biomass was found in the raft (1275.6 ± 33.4 g), followed by grow pipes (1042.0 ± 35.8 g) and gravel substrate (686.3 ± 98.2 g; raft > grow pipes > gravel). M. spicata, under aquaponics, grows best in grow pipe and raft components. An increase in pipe diameter for the grow pipes and a reduction in the channel height for the raft components could optimize aquaponic culture conditions for both industrial production and the hobby sector in the future.

Comparative study of two bioassays with weakened duckweed and yeast treated with homeopathic preparations

In homeopathic basic research, the question as to the most adequate test systems and apt methodology is still open. This investigation examined the hypothesis that more complex organisms show stronger reactions to homeopathic remedies than less complex ones. We compared two Arsenic (As5+) stressed bioassays with duckweed (Lemna gibba, a multi-cellular autotrophic organism) and yeast (Saccharomyces cerevisiae, a single-cellular heterotrophic organism) regarding their response to homeopathic preparations [1]. For duckweed, growth rates of leaf area and leaf number were evaluated. For yeast, growth kinetics were determined by measuring slope, yield and Et50 (point in time when yield was half maximum) of the sigmoid growth curve. The experiments with duckweed and yeast were performed in parallel (same day, same location and identical homeopathic preparations). After screening 17 substances, three homeopathic preparations (Arsenicum album, nosode, gibberellic acid) were chosen for repeated experimental series [2]. Five independent experiments were conducted for each remedy with both organisms in parallel. Potency levels used were in the range of 17x–33x for duckweed and 17x–30x for yeast. To control for test system stability, systematic negative control experiments were conducted over the complete experimentation period. All experiments were blinded and randomized. The systematic negative control experiments did not yield any significant effects. Application of potentized Arsenicum album in the duckweed bioassay yielded the largest effects compared to water controls without remedies for the parameters leaf area and leaf number (p

Assessment of the Effect of Cutting Length on Sprout and Growth of Pterocarpus santalinoides L’hérit. Ex Dc

Aims: This study evaluated the effect of cutting lengths on sprouts and seedling growth of P. santalinoides. Study Design: The experiment was laid out in a Completely Randomised Design (CRD). Place and Duration of Study: The study was carried out at the Department of Forestry and Wildlife Management Nursery, University of Port Harcourt, Rivers State, Nigeria, between April 2019 and March 2020. Methodology: Ten (10) cuttings per cutting length were planted in a polybag filled with forest topsoil. The treatments are; 13, 20, 25 and 33 cm cutting lengths. Five seedlings per treatment were randomly selected and dried for biomass. Emergence of sprouts, number of leaves and branches, survival rate, number of cuttings that sprouted, sprout length, root length and biomass were determined and subjected to analysis of variance. Results: Sprouts emergence occurred earliest in 25 cm cuttings (7 days) and latest in 13 and 20 cm cuttings (12 days). There were significant differences (P ≤ 0.05) in leaf number at month 1, number of branches at months 1, 3, 5 and 9, cutting length at month 2 and root to shoot ratio and non-significant differences (P > 0.05) in leaf number at months 3,5,7,9 and 11, number of branches at months 7 and 11, number of sprouts, cutting length at month 12, root length, shoot biomass, root biomass and total fresh and dry weight. Twenty five (25) cm long cutting enhanced sprout parameters while 33 cm long cutting enhanced root parameters. Conclusion: The result showed that 25 and 33 cm long cuttings are most suitable cutting lengths and are therefore recommended for growth of the species.

Growth Effect of the Different Ratios of Wood Vinegar on Brassica juncea

Four (4) different ratios of wood vinegar namely; 1:5; 1:10; 1:20 and 1:30 mL WV to water ratio extracted from coconut shell was tested to determine their growth effect on Brassica juncea or mustard plant or locally known as mustasa. Parameters measured were leaf number, plant height, plant leaf width. Using randomized complete block design, experimental tests were conducted using Brassica juncea as test plants. The samples of 10 days old were allowed to flourish in a potted plant with day to day application of the wood vinegar solutions together with the negative control for a total of 30 days. Results revealed that the wood vinegar ratios applied have no significant effect on the growth of the mustard plant in terms of its leaf number, plant height and leaf width. This indicates that coconut shell wood vinegar at 1:5, 1:10, 1:20 and 1:30 are not applicable ratios for plant production, as that an increased wood vinegar application increases plant production and growth.

Effects of Potassium Fertilization, Cultivar Specifics and Seedling Temperature Regime on Growth Parameters and Yield of Tomato (Solanum lycopersicum L.)

Background: Potassium fertilization shows beneficial effect on formation of tomato vegetative biomass and productivity. The purpose of this study was to determine the extent to which split potassium application and seedling temperature regime affects the growth parameters (leaf number, leaf area, fresh leaf weight and LAI) and yield of various tomato cultivars. Methods: A pot experiment was conducted to investigate the impact of single dose and split potassium fertilization treatments, cultivar specifics and seedling temperature regime on growth parameters and yield of tomato. Ten high yielding classic round shape tomato cultivars with determinate growth habitat were planted on Fluvisol. Single and split potassium fertilization treatments were tested. Result: The seedlings growth temperature regime and splitting the potassium fertilization treatment did not have a significant effect on the development of leaf biomass in tomato plants. Results revealed that leaf number, leaf area, fresh leaf weight and LAI of tomato plants was significantly affected by the cultivar genetic factor. Tomato yield were significantly affected by cultivars and split potassium fertilization treatments. Cultivars that measured the highest leaf area, fresh leaf weight and LAI and were also the highest yielding ones. A positive correlation between LAI and tomato fruit yield was observed.

The Relationships between Plant Developmental Traits and Winter Field Survival in Rye (Secale cereale L.)

Overwintering cereals accumulate low temperature tolerance (LTT) during cold acclimation in the autumn. Simultaneously, the plants adjust to the colder season by making developmental changes at the shoot apical meristem. These processes lead to higher winter hardiness in winter rye varieties (Secale cereale L.) adapted to Northern latitudes as compared to other cereal crops. To dissect the winter-hardiness trait in rye, a panel of 96 genotypes of different origins and growth habits was assessed for winter field survival (WFS), LTT, and six developmental traits. Best Linear Unbiased Estimates for WFS determined from five field trials correlated strongly with LTT (r = 0.90, p < 0.001); thus, cold acclimation efficiency was the major contributor to WFS. WFS also correlated strongly (p < 0.001) with final leaf number (r = 0.80), prostrate growth habit (r = 0.61), plant height (r = 0.34), but showed weaker associations with top internode length (r = 0.30, p < 0.01) and days to anthesis (r = 0.25, p < 0.05). The heritability estimates (h2) for WFS-associated traits ranged from 0.45 (prostrate growth habit) to 0.81 (final leaf number) and were overall higher than for WFS (h2 = 0.48). All developmental traits associated with WFS and LTT are postulated to be regulated by phytohormone levels at shoot apical meristem.

Studiul unor trăsături asociate cu productivitatea la hibrizi experimentali de floarea-soarelui

The relationships between seed yield and some morpho-physiological parameters, such as plant height, head diameter, leaf number, number and weight of total and full seeds per head and 1000 seeds in 32 local hybrids has been studied. The analyses of Pearson correlation coefficients showed significant, but low, positive correlations between yield and number of full seeds per calatidium, weight of total seeds per calatidium, weight of 1000 seeds and hectolitre weight. There were also observed positive correla-tions between plant height and number of leaves.