Determination of swithgrass (Panicum virgatum L.) seeds quality

Purpose. Developing a method for determination of the laboratory seed germination that could reduce the biological dormancy period and, accordingly, increase the intensity of germination. Methods. Laboratory, measuring and weighing, mathematical and statistical. Results. Cooling switchgrass seeds at a temperature of 10°C for 7 days on average for three years did not lead to a decrease in germination energy and germination compared to cooling for 14 days. These indexes were almost the same and amounted to 74 and 76%, 73 and 75%, respectively. There were no significant deviations in germination energy and seed germination over the years of research as affected by duration of the cool period. The production test of the developed method, carried out in the accredited control and measuring laboratory, confirmed the obtained in the laboratory results. Conclusions. Seed germination by an improved method, when pre-cooling is carried out for 7 instead of 14 days and counting of germinated seeds on 15th day instead of 20th, has reduced the time to determine germination by 13 days without reducing the quality of analysis. It is advisable to determine the 1000-seed weight in one of three ways, but the most accurate is the third way, i.e. counting the seeds in 10 repetitions.

The Role of Trees in Winter Air Purification on Children’s Routes to School

Air pollution is now considered to be the world’s largest environmental health threat accounting for millions of deaths globally each year. The social group that is particularly exposed to the harmful effects of air pollution is the children. A daily route to school can constitute an important component of children’s physical activity, but air pollution can pose a threat to their health. Numerous studies have proved high loads of PM can be effectively reduced by vegetation. Little is however known, whether vegetation can also reduce PM during the leaf dormancy period. In this study, we investigated the role of trees in PM removal on children’s routes to schools during winter. We investigated walking routes to selected schools in Warsaw, by examining the adjacent vegetation and PM2.5 and PM10 concentrations and the presence of local black-smoke-belching stoves. We found that proximity to local CHP emitters had the strongest impact on pollution on the way to schools, while not finding a significant relationship between dense greenery and PM loads. Even more, the highest density of vegetation along walking routes tended to stimulate higher PM concentrations. The results obtained show the poor performance of tree canopy in reducing PM loads during winter.

Socioeconomic impact of COVID-19 on Peruvian amazon aquaculture

The pandemic produced by COVID-19, is affecting all sectors worldwide. Aquaculture and fishing are not the exception. The measures taken by governments in order to dissipate contagions prevent supporting the economy. Faced with this situation, governments and state entities are taking measures to cushion and strengthen companies. However, to make correct decisions regarding aid, it is necessary to diagnose the state of the productive sectors in order to carry out interventions and manage solutions to priority problems. The objective of the present study was to establish information on the aquaculture production units in the San Martín region, which enables the aquaculture sector to be managed efficiently, promoting efforts and public interventions in the region. The results show that more than 90% of the aquaculture producers in the San Martín region are affected, mainly by logistical difficulties in the delivery of supplies, which have stopped the operation of approximately 18% of fish production. During the COVID-19 dormancy period, aquaculturists implemented some biosecurity measures, mainly handwashing, but it is necessary to establish protocols for good aquaculture production practices to strengthen health aspects that prevent the spread of the disease.

Shortening Dormancy Period of Oil Palm Seeds (Elaeis guineensis) using Sulfuric Acid (H2SO4) and Gibberellic Acid (GA3) Solutions

Soaking oil palm seeds in a solution of sulfuric acid and gibberellic acid is one way to shorten the dormancy period of oil palm seeds. This study aimed to find out the optimum soaking time of oil palm seeds in sulfuric acid solution to accelerate germination, the optimum concentration of gibberellic acid for oil palm seed germination, the interaction between using sulfuric acid and gibberellic acid in accelerating the germination of oil palm seeds and the best treatment combination in all the tried treatments. The experimental design used was a completely randomized design (CRD), with a complete factorial combination with a total of 16 treatments. Each treatment was repeated 4 times, so there were 64 experimental units and each unit was planted with 5 seeds. The results of statistical analysis showed that soaking oil palm seeds in a solution of sulfuric acid and gibberellic acid had an effect on the germination of these seeds. The duration of soaking oil palm seeds for 48 hours in sulfuric acid solution constituted the optimum time for increasing the speed of germination and giving gibberellic acid at a concentration of 300 ppm still accelerated the germination of oil palm seeds and there was no interaction between the length of soaking the seeds in sulfuric acid solution and the concentration of gibberellic acid. Soaking the seeds in a solution of sulfuric acid for 48 hours and gibberellate 300 ppm was the best combination treatment to accelerate the germination of oil palm seeds.

The estimation of Trollius L. species and hybrids by seed germination

The article describes the laboratory germination and seed dormancy duration of five Trollius species andfour hybrids, which has been grew ex situ. The species and forms with high seed germination were detected from the dataobtained: T. ledebourii Rchb. (92 %), T. chinensis Bunge (93,5 %) end T. chinensis × T. ledebourii (82 %). Besides a high germination, the T. ledebourii seeds have the short dormancy period (22 days) and good sprouts. Therefore, the T. ledebourii seeds can be recommended for both autumn and spring sowing. The above mentioned Trollius species and forms arepotential for ornamental cultivar creation by further selection. The seeds of following species and forms T. apertus Perf.ex Igoschina, T. europaeus L., T. sajanensis (Malyschev) Sipliv., T. asiaticus × T. sajanensis, T. ledebourii × T. altaicus and T.× cultorum have low germination and long dormancy period. The examination of stratification treatment parameters andagrotechnical measures is needed for the germination of these seeds to get higher.

Phenology of flowering and fruiting and effect of KNO3 and H2O2 on germination process of amorphophallus muelleri blume

Amorphophallus muelleriBlume also known as Indonesian Konjac (IK, in short) is a wild plant that spreads out in Indonesia especially in the southern part. The genus Amorphophalluscan also be found in some countries in South-East Asia. The IK tuber contains glucomannan, a compound which has high economic value as raw material in many industries such as food, drink, pharmacy, cosmetics, paper, rubber, textile, film industries and many others. The plant is easy to cultivate. Due to the economic benefit of IK tubers and to the easiness of its cultivation, this study was carried out to increase the productivity of glucomannan. The current productivity is still low compared to foreign demand. For example, in 2020 alone, according to the Ministry of Agriculture, Republic of Indonesia, only 12 % of foreign demand have been fulfilled. Therefore, there is an urgent need to increase the productivity of IK tubers. This is the main problem of this research. Its objectives were two-fold. First, was to study the effect of tuber weight on flowering percentage, flower size, and fruiting which is represented by the number of fruits and the number of seeds. Second, was to find out the right concentration of KNO3and H2O2solutions as well as the soaking time in those solutions to break the dormancy period and to increase the germination rate. For these purposes, a laboratory experiment using completely randomized design with three treatments was conducted and the collected data were analyzed using general linear model, analysis of variance and multiple comparison test. The results indicate that the tuber weight significantly affects the flowering percentage, flower size, number of fruits and number of seeds of IK. The heavier the planted tuber, the higher the flowering percentage and the larger the flower size, number of fruits and number of seeds. The response on dormancy breaking treatment indicates that there is no significant effect of soaking treatment in KNO3 and H2O2 solutions on dormancy period of the IK seeds. The KNO3and H2O2solutions have only effect on increasing the germination rate and on shortening the time period for seeds to germinate. Moreover, unlike H2O2, there is no residual effect of KNO3on seeding growth, and on weight and shape of the IK tuber. To the knowledge of the authors, these findings are unprecedented and could thus,contribute to the literature.

Epidemiology studies of Pseudomonas syringae pathovars associated with bacterial canker on the sweet cherry in Serbia

This study was conducted to examine the epidemiological characteristics of two Pseudomonas syringae pvs. – syringae (Pss) and morsprunorum race 1 (Psm) on the sweet cherry in both field and laboratory conditions. Cycled inoculations of one-year-old branches indicated that the sweet cherry became sensitive to Psm race 1 earlier in the season (October) compared to Pss (November). The most severe infections occurred in the dormancy period (November), while the necroses formed in January and March were less in their length. Inoculations of the two-/three-year-old branches performed in November resulted in necrosis, with those induced by Pss being more aggressive. The January inoculations, however, resulted in less formed necroses in length. Laboratory tests performed on excised sweet cherry branches confirmed the results yielded by the field experiments, indicating that the dormancy period poses the greatest risk for the P. syringae pvs. infection. The isolation of Pss and Psm bacteria from naturally infected sweet cherry samples (cankers) during the summer indicated that the bacteria that persists in cankers in low numbers became active during autumn. Significant Pss and Psm race 1 epiphytic bacterial populations were noted during the spring, but decreased in the summer and increased again in the autumn, indicating the presence of inoculum reservoirs. The greater understanding of the control strategies aimed at the epidemiological factors should, thus, facilitate better disease outbreak management.

Studies of Vegetative Growth, Inflorescence Development and Eco-Dormancy Formation of Abscission Layers in Streptocarpus formosus (Gesneriaceae)

Streptocarpus formosus (Hilliard & B.L. Burtt) T.J. Edwards is a flowering herbaceous perennial indigenous to South Africa and is part of the rosulate group of herbaceous acaulescent plants within the Gesneriaceae family. According to the National Assessment database for the Red List of South African Plants version 2020.1., the plant is listed as rare. The ornamental use of S. formosus has untapped commercial potential as a flowering indoor pot plant, an outdoor bedding plant for shade and as a cut flower for the vase, all of which are limited by a five-month eco-dormancy period during the late autumn and all through the cold season in the short-day winter months. Viable commercial production will require cultivation techniques that produce flowering plants all year round. This study investigated the effectiveness of applying root zone heating to S. formosus plants grown in deep water culture hydroponics during the eco-dormancy period in preventing abscission layer formation and in encouraging flowering and assessed the growth activity response of the plants. The experiment was conducted over eight weeks during the winter season in the greenhouse at Kirstenbosch Botanical garden in water reservoirs, each maintained at five different experimental temperature treatments (18, 22, 26—control, 30 and 34 °C) applied to 10 sample replicates. The results showed that the lowest hydroponic root zone temperature of 18 °C had the greatest effect on the vegetative growth of S. formosus, with the highest average increases in fresh weight (1078 g), root length (211 cm), overall leaf length (362 cm) and the number of newly leaves formed (177 = n), all noted as statistically significant when compared with the other water temperature treatments, which yielded negative results from reduced vegetative growth. Findings from the study also revealed that while all heated solutions significantly prevented the formation of abscission layers of S. formosus, they had a less significant effect on inflorescence formation, with only 18 °C having the greatest positive effect on flower development.

Multivariate analysis of geographically diverse rice germplasm for genetic improvement of yield, dormancy and shattering-related traits

A diverse set of 107 rice genotypes was evaluated for yield, shattering and dormancy traits. Analysis of variance revealed sizable variation while skewness and kurtosis values indicated near-normal distribution for most of the traits, thus quantitative nature controlled by many genes. A highly significant deviation from a normal distribution for dormancy and shattering % indicated their qualitative nature of inheritance. Four promising genotypes ‘IRGC1723’ (early with 65 days to flowering), ‘IRGC 11108’ and ‘RNR 15459’ (high grain number – 358 and low average shattering – <5%), ‘RNR 11718’ (high single plant yield – 56.73 g, low average shattering – <5% and dormancy period – 21 days) are identified. A significant positive correlation between shattering and dormancy confirms inter-relationship among domestication-related characteristics. The principal component analysis revealed the contribution of four PCs to maximum variability and hierarchical clustering grouped the genotypes into 18 divergent clusters. Five cultivars (Karimnagar Samba, Sheetal, PR 121, Pranahitha and Jagitial Samba) with a combination of low shattering ability (3.35–5.7%) and considerable dormancy period (13–20 days) falling in the same cluster can be used as donors for the improvement of rice genotypes with low shattering ability and incorporating a considerable period of dormancy so as to avoid pre-harvest sprouting due to delayed harvesting. Further, they can be crossed with ‘Pratyumna’ having less than 1 week dormancy period, a genotype of the cluster XVII with which they have a maximum genetic divergence of 51.4 and may serve as parents in the development of mapping populations for the identification of QTLs/genes for shattering and dormancy traits.