EFFECT OF SWARD TYPE, CUTTING FREQUENCY AND FERTILIZER-N APPLICATION ON PASTURE ESTABLISHMENT, GROWTH AND YIELD IN GUINEA GRASS-VERANO STYLO PASTURES

ABSTRACT This experiment was a 3 x 3 x 2 factorial laid out in a randomized complete block design and was replicated three times. Treatments comprised three sward types (pure grass, pure legume and grass/legume mixed swards), three cutting regime

Expression analysis of Clavata1-like and Nodulin21-like genes from Pinus sylvestris during ectomycorrhiza formation

The ecology and physiology of ectomycorrhizal (EcM) symbiosis with conifer trees are well documented. In comparison, however, very little is known about the molecular regulation of these associations. In an earlier study, we identified three EcM-regulated Pinus expressed sequence tags (EST), two of which were identified as homologous to the Medicago truncatula nodulin MtN21. The third EST was a homologue to the receptor-like kinase Clavata1. We have characterized the expression patterns of these genes and of auxin- and mycorrhiza-regulated genes after induction with indole-3-butyric acid in Pinus sylvestris and in a time course experiment during ectomycorrhizal initiation with the co-inoculation of 2,3,5-triiodobenzoic acid, an auxin transport inhibitor. Our results suggest that different P. sylvestris nodulin homologues are associated with diverse processes in the root. The results also suggest a potential role of the Clv1-like gene in lateral root initiation by the ectomycorrhizal fungus

Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch

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Cadophora margaritata sp. nov. and other fungi associated with the longhorn beetles Anoplophora glabripennis and Saperda carcharias in Finland

Symbiosis with microbes is crucial for survival and development of wood-inhabiting longhorn beetles (Coleoptera: Cerambycidae). Thus, knowledge of the endemic fungal associates of insects would facilitate risk assessment in cases where a new invasive pest occupies the same ecological niche. However, the diversity of fungi associated with insects remains poorly understood. The aim of this study was to investigate fungi associated with the native large poplar longhorn beetle (Saperda carcharias) and the recently introduced Asian longhorn beetle (Anoplophora glabripennis) infesting hardwood trees in Finland. We studied the cultivable fungal associates obtained from Populus tremula colonised by S. carcharias, and Betula pendula and Salix caprea infested by A. glabripennis, and compared these to the samples collected from intact wood material. This study detected a number of plant pathogenic and saprotrophic fungi, and species with known potential for enzymatic degradation of wood components. Phylogenetic analyses of the most commonly encountered fungi isolated from the longhorn beetles revealed an association with fungi residing in the Cadophora-Mollisia species complex. A commonly encountered fungus was Cadophora spadicis, a recently described fungus associated with wood-decay. In addition, a novel species of Cadophora, for which the name Cadophora margaritata sp. nov. is provided, was isolated from the colonised wood.Peer reviewe

Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch

Silver birch (Betula pendula) is a pioneer boreal tree that can be induced to flower within 1 year. Its rapid life cycle, small (440-Mb) genome, and advanced germplasm resources make birch an attractive model for forest biotechnology. We assembled and chromosomally anchored the nuclear genome of an inbred B. pendula individual. Gene duplicates from the paleohexaploid event were enriched for transcriptional regulation, whereas tandem duplicates were overrepresented by environmental responses. Population resequencing of 80 individuals showed effective population size crashes at major points of climatic upheaval. Selective sweeps were enriched among polyploid duplicates encoding key developmental and physiological triggering functions, suggesting that local adaptation has tuned the timing of and cross-talk between fundamental plant processes. Variation around the tightly-linked light response genes PHYC and FRS10 correlated with latitude and longitude and temperature, and with precipitation for PHYC. Similar associations characterized the growth-promoting cytokinin response regulator ARR1, and the wood development genes KAK and MED5A.Peer reviewe

Biocontrol Potential of Forest Tree Endophytes

Peer reviewe

Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch.

Silver birch (Betula pendula) is a pioneer boreal tree that can be induced to flower within 1 year. Its rapid life cycle, small (440-Mb) genome, and advanced germplasm resources make birch an attractive model for forest biotechnology. We assembled and chromosomally anchored the nuclear genome of an inbred B. pendula individual. Gene duplicates from the paleohexaploid event were enriched for transcriptional regulation, whereas tandem duplicates were overrepresented by environmental responses. Population resequencing of 80 individuals showed effective population size crashes at major points of climatic upheaval. Selective sweeps were enriched among polyploid duplicates encoding key developmental and physiological triggering functions, suggesting that local adaptation has tuned the timing of and cross-talk between fundamental plant processes. Variation around the tightly-linked light response genes PHYC and FRS10 correlated with latitude and longitude and temperature, and with precipitation for PHYC. Similar associations characterized the growth-promoting cytokinin response regulator ARR1, and the wood development genes KAK and MED5A

Author Correction: Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch.

In the version of this article initially published, there was a mistake in the calculation of the nucleotide mutation rate per site per generation: 1 × 10−9 mutations per site per generation was used, whereas 9.5 × 10−9 was correct. This error affects the interpretation of population-size changes over time and their possible correspondence with known geological events, as shown in the original Fig. 4 and supporting discussion in the text, as well as details in the Supplementary Note. Neither the data themselves nor any other results are affected. Figure 4 has been revised accordingly. Images of the original and corrected figure panels are shown in the correction notice

The challenges of crop production in Nigeria for the 21st century

Before and at the dawn of independence in 1960, Nigeria had a thriving agrarian economy, with food surplus projected for the 70s. The food surplus never happened because of the neglect of agriculture resulting from a thriving oil economy to the extent that presently oil accounts for 94 - 95% of Nigeria's foreign exchange earnings. In the present article, attempts have been made to identify the major challenges and aims of crop and forestry agriculture with a case made for the ways to make crop agriculture to play a robust and more competitive role in the 21st century. Nigeria's endowment in crop and environmental resources were shown to be favourable for agricultural development. Ways ahead for agricultural development in the 21st century were surveyed. Use of proved good quality planting materials based on a good breeding programme which necessitates emergence of indigenous seed firms with commercial orientation, and uses of integrated pest management procedures were strongly emphasized. The right production system and mechanization strategies must be products of research and development based on local conditions and not mere importations based on alien conditions. Agroforestry, with its multiple benefits, was shown to be environmentally friendly and capable of benefiting sustainable production if well programmed into use. Conservation of Nigeria's fast disappearing wealth of genetic resources as a basis for development of crop idiotypes was seen as a great debt owed to the future generation. Biotechnology, like the Green Revolution of the 20th century, was identified as probably the unfolding revolutionary technology for the 21st century, that may alter the course of agricultural development, and in which Nigeria must play a competitive role to remain relevant in 21st century agriculture

Decomposition of Cassava and Vegetable Cowpea leaf litters under field and Laboratory conditions

Management of plant residues is critically important in keeping the soil supplied with essential nutrients, the supply of which depends on the decomposition of the plant materials. Two related studies using three leaf residue types' cassava and vegetable cowpea leaves were carried out in the field and under controlled laboratory conditions to determine the rate of their decomposition using litter bag technique. The carbon dioxide evolution by the three leaf residues namely, Oven dry leaf litter, fresh leaf litter and green leaf of both cassava and cowpea was also monitored for twelve weeks. All the residues attained up to 90% decomposition in the short period of time. While the periodic carbon dioxide evolution decreased, the cumulative evolution increased with length of incubation. The control had the least carbon dioxide evolution.Nigerian Journal of Soil Science Vol. 17 2007: pp. 38-4