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Boryana Dyulgerova and Nikolay Dyulgerov

Abstract

The aim of this study was to examine the genotype by environment interaction for grain yield and to identify high-yielding and stable mutant lines of 6-rowed winter barley under different growing seasons. The study was carried out during 7 growing seasons from 2010 – 2011 to 2016 – 2017 in the experimental field of the Institute of Agriculture – Karnobat, Southeastern Bulgaria. Fourteen advanced mutant lines and the check variety Vesletc were studied using a complete block design with 4 replications. The AMMI analysis of variance indicated that 20.54% of the variation for grain yield was explained by the effect of genotype and 37.34% and 42.12% were attributable to the environmental effects and genotype by environment interaction. The magnitude of the genotype by environment interaction was two times larger than that of genotypes, indicating that there was a substantial difference in genotype response across environments. The AMMI and GGE biplot analyses identified G9 as the highest yielding and stable genotype. This mutant line can be recommended for further evaluation for variety release. The mutant lines G6, G13 and G15 were suggested for inclusion in the breeding program of winter barley due to its high grain yield and intermediate stability.

Open access

Lars Hedenäs and Irene Bisang

Abstract

In the Baltic area, the long-lived dioicous wetland moss Drepanocladus turgescens (T.Jensen) Broth. produces sporophytes rarely and at irregular intervals. Based on surveys of sporophyte occurrences at 13 sites in two regions in northern Gotland (Sweden) during three to five years, we ask: (1) Is sporophyte formation associated with precipitation and a precipitation index that considers the dry periods during July-August of the preceding year, when gametangia are formed and fertilization occurs? (2) Does the estimated spore output suffice for the species’ long-term persistence of the (Northern) European population species? In one of the study regions, where D. turgescens occurs in depressions, sporophyte formation was associated with the two precipitation parameters. In the other study region, with relatively higher precipitation and exposed occurrences on a slightly sloping bedrock with very little accumulated soil, no such association existed. We suggest that this lack of weather effects results from that the exposed rock habitat requires longer continuously wet periods than the depression habitat to allow for gametangia initiation and development, and fertilisation. Average spore production for six spore capsules, from three Gotland localities was 181,000. Based on the sporophyte counts during the survey years, we estimated the total reproductive output as 411.5 million spores in 2013, and 42.5 million in 2015, in the two respective study regions. Taken together with data on haplotype patterns and considering observations on recent colonisations, we argue that such a relatively low and episodic regional spore production is sufficient to maintain global populations of long-lived species, even if these occur in specialized and geographically restricted habitats.

Open access

József Zsembeli, Lúcia Sinka, Arzu Rivera-García, Krisztina Czellér, Géza Tuba, Koloman Krištof and Pavol Findura

Abstract

The research work was started on the preliminary knowledge that the risk of secondary salinization is high in the hobby gardens around Karcag as the water of the aquifers used for irrigation is saline, nevertheless irrigation in the drought periods is essential for vegetable production. A complex experiment was set up in 12 simple drainage lysimeters at the lysimeter station of the Research Institute of Karcag in 2012 in order to simulate the conditions of irrigation characteristic in the region with the goal of finding a solution to mitigate the harmful effects by means of optimization of irrigation. In 2017–2018 three approaches were applied for the scientific establishment of the problem studying the effect of different irrigation frequencies, different irrigation water qualities, and soil conditioning on the moisture content and the salt profile of the soil. The soil conditioner (Neosol) applied was found to have a positive effect on the water and salt regime of the soil, partly by creating a more favourable vertical distribution of the soil water, and partly preserving more moisture in the soil.

Open access

Juan A. Jiménez and María J. Cano

Abstract

A new moss species, Didymodon ochyrarum J.A. Jiménez & M.J. Cano, is described and illustrated from the tropical Andean highlands of Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile and Argentina. The species is distinguished morphologically by its lanceolate to long-lanceolate leaves that are strongly appressed when dry, leaf base widely ovate, acute apices, plane leaf margins and distally bistratose, excurrent costa, epapillose laminal cells, and marginal basal cells running up the margin forming a distinctly differentiated area of transversely thick-walled cells. Drawings and light microscope photographs of the new species are provided, and possible confusion with other closely related taxa is discussed.

Open access

Amanul Islam, Shahinur Kabir and Abul Khair

Abstract

In quest of prospective rizospheric bacteria of agricultural importance, one of the isolates from bean (Lablab niger Medikus) was identified as Bacillus siamensis based on morphological, biochemical and 16S rRNA gene sequencing data. Study was carried out to evaluate growth promotion of two tomato cultivars, in vitro and in vivo. Experiments conducted for two consecutive years, following seed treatments revealed that the bacterial isolate increased plant height by 14.66‒15.68%, shoot fresh weight by 34.5‒65.09% and root fresh weight by 75.3‒92.48% over the non-treated control. The bacterial strain showed encouraging results for plant growth promotion in pot study and hence may be useful for the growth enhancement of tomato plant.

Open access

Dale H. Vitt

Abstract

Terrestrial mosses dominate the ground in many vegetation types and most are long-lived perennials with highly complex canopies. Long-term population health continues through numerous wetting and drying cycles; however, extreme drought or extended wet periods may create conditions that cause some parts of the population to die or remain inactive. I examined apparent photosynthesis of fully hydrated populations of four terrestrial species of mosses occurring in leaf-free mesohabitats in temperate deciduous forests of eastern North America in order to explore photosynthetic variability of both popula-tions and species. There was high variability in rates of apparent photosynthesis among the popula-tions of mosses for all four species examined in this study. Despite this variability within species, all four species achieved similar mean rates of photosynthesis. Two years after relocation to nearly bare ground habitats, populations of three of the four species achieved similar apparent photosynthetic rates as natural popula-tions, and functioned in a similar manner.

Open access

Johannes Enroth, Tamás Pócs, Xiaolan He, Petri Nyqvist, Åsa Stam, Itambo Malombe and Jouko Rikkinen

Abstract

Based on previous literature and our own collections, we list 285 bryophyte species (142 liverworts, 143 mosses) from the Taita Hills region (including Mt. Kasigau and Maktau Hill) in SE Kenya. New records for Kenya include the liverworts Archilejeunea elobulata Steph., Bazzania nitida (F. Weber) Grolle, Cololejeunea grossepapillosa (Horik.) N. Kitag., Diplasiolejeunea kraussiana (Lindenb.) Steph., D. villaumei Steph., Lejeunea amaniensis E.W. Jones, L. cyathearum E.W. Jones, Lopholejeunea laciniata E.W. Jones, Metzgeria crassipilis (Lindb.) A. Evans, M. nudifrons Steph., Plagiochila boryana (F. Weber) Nees, and P. moenkemeyeri Steph., and the mosses Leucophanes hildebrandtii Müll. Hal. and Neckeromnion lepineanum (Mont.) S. Olsson, Enroth, Huttunen & D. Quandt. A further 22 liverworts and 13 mosses previously known from other parts of Kenya are reported for the first time from the Taita Hills region.

Open access

Frank Müller, Thea Lautenschläger and James R. Shevock

Abstract

Five liverwort species (Cheilolejeunea krakakammae, Cololejeunea latilobula, Cylindrocolea abyssinica, Telaranea nematodes, Thysananthus humilis) and five moss species (Calyptothecium planifrons, Calymperes tenerum, Fissidens usambaricus, Leptotrichella nitidula, Trichostomum lorifolium) are reported as new for the bryophyte flora of Angola. Fossombronia indica is reported as new for the country of São Tomé and Príncipe, Gulf of Guinea, West Africa. An additional two hepatic species (Lejeunea acuta, Solenostoma dusenii) are reported as new for Príncipe.

Open access

Jolanta Bąk-Badowska, Ilona Żeber-Dzikowska, Barbara Gworek, Wanda Kacprzyk and Jarosław Chmielewski

Abstract

This article refers to the biology and ecology of stingless bees (Meliponini), living in tropical and subtropical areas. Similar to honey bees (Apis mellifera), stingless bees (Meliponini) belong to the category of proper social insects and are at the highest level of social development. This group of insects comprises about 500 species and they are the most common bees pollinating the native plants in many tropical areas. Families of stingless bees are usually quite numerous, reaching up to 100,000 individuals. They are characterised by polymorphism, age polyethism and perennialism. This article presents the structural complexity of natural nesting of these tropical insects and their ability to settle in artificial nest traps. The main significance of stingless bees for humans is their role in the natural environment as pollinators, which is an essential factor influencing biodiversity.

Open access

Jadwiga Sienkiewicz, Grażyna Porębska, Apolonia Ostrowska and Dariusz Gozdowski

Abstract

Peat mineralisation leads to net loss of CO2 to the atmosphere, as well as to release of other elements from the decomposed soil organic matter (SOM) to groundwater. This results in the degradation of peat soils and the ecosystems they support. Here we evaluated the practical indicatory suitability of the existing and proposed new indices for the assessment of peat soil degradation in the Biebrza river valley encompassing, unique on European scale, peatland ecosystems. We studied relationships between soil organic carbon (SOC) and total nitrogen (Ntot), dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in a series of degraded peat soils in the Biebrza valley. Samples were taken from soils developed on peat deposits that varied in thickness and the degree of peat decomposition, from undegraded to highly mineralised peats. The relationships between changes in the SOC content and changes in the values of the remaining variables (SOM, Ntot, DOC, DON, C/N ratio), were statistically tested. Linear and non-linear regressions were used to establish the relationships amongst the variables examined. The losses of soil C and N occur independently and differ between stages of peat soil mineralisation. From our study, it results that the peat mineralisation intensity may be estimated based on the loss of SOC. We found that 1% loss of SOC corresponded to 1.028% loss of SOM, regardless of the degree of peat soil mineralisation, whereas SOM solubility, measured by the content of DOC, varied based on the intensity of peat soil mineralisation. The content of DOC decreased with the decrease in the SOC content, whereas the DOC/ SOC ratio increased depending on the intensity of peat decomposition. The C/N ratio is not a reliable indicator of peat mineralisation, because its values are driven not only by the nitrogen natively present in peat soils but also by nitrogen from external sources. The contents of SOC and Ntot did not decrease uniformly during peat decomposition because C and N show various mobility in the processes of SOM mineralisation. We found that the DOC/SOC ratio was most indicative of peat soil mineralisation intensity.

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