Aspirations and needs of farmers on communal grazing areas in the Free State

The study evaluated the needs and aspirations of farmers in communal or commonage grazing systems in the Free State. The study focused on communal grazing systems in Qwaqwa, Thaba-Nchu, Botshabelo as well as parts of areas in the Free State where commonage grazing systems are practiced by small-scale farmers. In this study the needs and aspirations of the farmers are related to the integration of environmental planning into communal grazing systems in the Free State, as well as security of tenure, working capital, knowledge, adequate extension services, training and water supply, timely veld fires, and co-operation amongst farmers. The needs and aspirations of livestock owners in the communal rangelands of the Free State are constrained by small farm size, population pressure, land tenure problems, distance from markets, poor transport and infrastructure. The study also reveals that integration of environmental planning into communal grazing systems in the Free State is essential for the best cattle performance and land use. South African Journal of Agricultural Extension Vol.32 2003: 85-9

Genetic Diversity and Population Structure of Saccharomyces cerevisiae Strains Isolated from Different Grape Varieties and Winemaking Regions

We herein evaluate intraspecific genetic diversity of fermentative vineyard-associated S. cerevisiae strains and evaluate relationships between grape varieties and geographical location on populational structures. From the musts obtained from 288 grape samples, collected from two wine regions (16 vineyards, nine grape varieties), 94 spontaneous fermentations were concluded and 2820 yeast isolates were obtained that belonged mainly (92%) to the species S. cerevisiae. Isolates were classified in 321 strains by the use of ten microsatellite markers. A high strain diversity (8–43 strains per fermentation) was associated with high percentage (60–100%) of fermenting samples per vineyard, whereas a lower percentage of spontaneous fermentations (0–40%) corresponded to a rather low strain diversity (1–10 strains per fermentation)

Use of a Generalized Additive Model to Investigate Key Abiotic Factors Affecting Microcystin Cellular Quotas in Heavy Bloom Areas of Lake Taihu

Lake Taihu is the third largest freshwater lake in China and is suffering from serious cyanobacterial blooms with the associated drinking water contamination by microcystin (MC) for millions of citizens. So far, most studies on MCs have been limited to two small bays, while systematic research on the whole lake is lacking. To explain the variations in MC concentrations during cyanobacterial bloom, a large-scale survey at 30 sites across the lake was conducted monthly in 2008. The health risks of MC exposure were high, especially in the northern area. Both Microcystis abundance and MC cellular quotas presented positive correlations with MC concentration in the bloom seasons, suggesting that the toxic risks during Microcystis proliferations were affected by variations in both Microcystis density and MC production per Microcystis cell. Use of a powerful predictive modeling tool named generalized additive model (GAM) helped visualize significant effects of abiotic factors related to carbon fixation and proliferation of Microcystis (conductivity, dissolved inorganic carbon (DIC), water temperature and pH) on MC cellular quotas from recruitment period of Microcystis to the bloom seasons, suggesting the possible use of these factors, in addition to Microcystis abundance, as warning signs to predict toxic events in the future. The interesting relationship between macrophytes and MC cellular quotas of Microcystis (i.e., high MC cellular quotas in the presence of macrophytes) needs further investigation

Identification of yeast population dynamics of spontaneous fermentation in Beijing wine region, China

The aim of this study was (i) to investigate changes occurring in the yeast population profile during spontaneous fermentation of grape juice; (ii) to assess the proliferation of commercial yeast starter culture strains in vineyards; and (iii) to identify indigenous wine strains for future development of starter strains that better reflect the yeast biodiversity of China’s grape-growing regions. To achieve this, yeasts were isolated at four different stages during fermentation of both hand-pressed and winery-sourced must samples of Vitis vinifera L. cv. Roussanne and Merlot. A total of 1600 yeast colonies were isolated and then grouped according to macroscopic and microscopic characteristics. A selection of 291 colonies from the different groups was subjected to species identification using the internal transcribed spacer regions of the 5.8S rRNA gene (ITS1-5.8S-ITS2 region) and the inter-delta () sequence of the 26S rRNA D1/D2 region. In addition, 104 Saccharomyces cerevisiae colonies were subjected to strain identification. Twelve species belonging to nine different genera were found amongst the isolates. During the early stages of fermentation, it was found that Hanseniaspora uvarum and Candida stellata numerically dominated the four to six yeast species present, including a region-specific yeast, Sporobolomyces beijingensis. Two S. cerevisiae strains were isolated from the final stage of fermentation. These two indigenous strains, which were found to be different from the nine commercial yeast strains previously used as starter cultures in this particular Beijing-based winery, might possess potentially important region-specific oenological characteristics. This study provides the first essential step towards the preservation and exploitation of the hidden oenological potential of the untapped wealth of yeast biodiversity in China’s wine-producing regions.Huihui Sun, Huiqin Ma, Meiling Hao, Isak S. Pretorius and Shangwu Chenhttp://www.annmicro.unimi.it/contents/contents59-1.ht