Performance of Four Rice Cultivars Transplanted Monthly over Full Year under Irrigated Conditions in Tanzania

In Tanzania, the phenology and seasonal variations of the yields of different rice cultivars have rarely been studied, especially under fully-irrigated conditions. A trial was conducted to identify the most suitable calendar for rice production in Tanzania under fully-irrigated conditions. Four popular rice cultivars, NERICA1, Wahiwahi, IR64 and TXD306, were transplanted monthly from January to December 2011. The four cultivars recorded similarly higher or lower yields than the annual means when transplanted in July （0.50-0.57 kg/m2） and April （0.07-0.31 kg/m2）. A yield-ranking analysis showed that plants transplanted in July was the most productive while those transplanted in April was the least productive, and also revealed a yield-seasonality for irrigated rice in Tanzania, a low-yield season （April-May）, a high-yield season （June-August）, and an unstable-yield season （September-March）. These yield seasons would appear to be closely linked to seasonal temperature variations. When transplanted in April-May, plants were exposed to very low temperatures between panicle initiation and flowering, apparently reducing yield through cold-induced sterility. Those transplanted in June-August prolonged their growth under relatively low temperatures and increased yield through increasing biomass production. In September- March, yield levels varied greatly due to the shortened phenological growth durations at higher temperatures. We conclude that under fully-irrigated conditions in Tanzania, rice should be transplanted in July to ensure the maximum production and yield stability. The yield-seasonality suggests that implementing measures to protect plants from low and high temperature stress at critical phenological stages may allow year-round rice production under fully-irrigated conditions in Tanzania.

Investigation of the microbiota associated with traditionally produced fruit vinegars with focus on acetic acid bacteria and lactic acid bacteria

The microbiological properties of traditionally produced fruit vinegars,i.e.,fig,mulberry,apple and plum vinegars,supplied from different cities in Turkey were investigated.The counts of acetic acid bacteria(AAB),lactic acid bacteria(LAB)and mold-yeast for fruit vinegars were found in the range of 2.54–7.05,1.91–6.81 and 1.32–7.10 log CFU/mL,respectively.The indigenous AAB and LAB isolates were recovered from the vinegars and characterized based on a combination of phenotypic and genotypic approaches including 16S rRNA gene sequencing.In AAB three different species,Acetobacter pasteurianus,A.ghanensis and A.fabarum,and in LAB five species,Lacticaseibacillus paracasei,Lactiplantibacillus plantarum,Levilactobacillus brevis,Leuconostoc sp.and Weisella confusa were identified in the vinegar samples.It was the first study reporting the identification of A.fabarum and Leuconostoc sp.,which were isolated from fig vinegar.The results of the study showed that A.pasteurianus and L.paracasei were predominant species found in vinegar samples.The study provides potential strains which may be used as starter cultures in food industry.