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In vitro control of oxidative browning: Case of amaryllis (Amaryllis belladonna L.)

Contrôle du brunissement enzymatique en culture in vitro: Cas de l’amaryllis (Amaryllis belladonna L.)





1 Laboratoire des Sciences Horticoles, Universités de Carthage. Institut National Agronomique de Tunisie, 43 Avenue Charles Nicolle, Tunis 1082, Tunisie.

Abstract – Oxidative browning is one of the main problems in plant tissue culture systems caused by the accumulation and oxidation of phenolic compounds and limits their propagation. To prevent and to overcome this limitation a number of techniques and antioxidant products such as activated charcoal and ß-Cyclodextrin were applied during the initiation phase of Amaryllis; sensitive plant to oxidative browning : Amaryllis belladonna L. The obtained results showed that media supplemented with 2 g/l of activated charcoal exhibited lower browning intensities and, at the same time, the survival and recovery rates of the explants were about 80 %. The ß-Cyclodextrin added to 1 g/l in the culture media also has an effect on the control of enzymatic browning. However, its action remains inferior to that of charcoal and gives similar results only when the pH is lowered to approximately 4.5. Acidic media at pH 4.5, outside the area of activity of polyphenol oxidases, also, limit browning.

Keywords: Enzymatic browning, amaryllis, in vitro culture, antioxidants

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Impact of somatic cell counts on milk production and chemical composition of raw milk

Impact des cellules somatiques sur la production laitière et la composition chimique du lait cru




1 High Institute of Agriculture Chott-Meriam Sousse Tunisia

Abstract – Besides its use for determining udder health status, somatic cell counting (SCC) is considered as one of the most determinant factors of milk quality. The objective of this study is to determine the effect of SCCs on individual milk production as well as on chemical composition of raw milk. The obtained results showed that SCC was positively correlated with milk production. Animals with SCC below 300 000 cells/ml showed the highest milk production (19.38 l/d) while animals with SCC above 106 cells/ml showed the lowest production (17.34 l/d). Correlation tests revealed that SCC, fat and protein contents in milk are positively correlated. The fat and protein levels in milk of animals with SCC less than 300 000 cells/ml were respectively 36.1 and 31.4 g/l while those of animals with SCC exceeding 10cells/ml were 36.8 and 32.5 g/l respectively, with 0.7 g/l difference for fat and 1.1g/l for protein content. The urea level was negatively correlated with the SCC. Milk with SCC below 300 000 cells/ml showed the highest urea level (21.68 g/l), while the lowest level (18.74 g/l) was recorded for milk from animals with SCC above 106 cells/ml.

Keywords: Raw milk, somatic cells, chemical composition, milk production

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Estimation of correlation, regression and heritability among barley (Hordeum vulgare L.) accessions




1 Pôle Régional de Recherche Développement Agricoles du Nord-Ouest semi-aride à El Kef, Institution de la Recherche et de l'Enseignement Supérieur Agricoles (IRESA), Tunisie

Higher School of Agriculture of Kef, University of Jendouba, Tunisia

Field crops Laboratory. INRAT, Université de Carthage, Tunisia

Abstract – Twenty-four barley accessions were grown in 2016 and 2017 successive seasons in order to estimate the variability of some desired traits and to study the amount of variation for different parameters. Genetic parameters, correlations, regressions and variance were estimated for all the traits. The highest positive correlation was obtained between grain yield and thousand kernels weight (TKW). Heading date was found to be negatively correlated with grain yield. For all traits, the genotype effect was much stronger than the environment effect for all traits ranging from 73.1% for yield to 97.5 % for TKW. This effect was explained by heritability ranging from 0.61 for plant height to 0.98 for Kernels number per spike (KNS). A large phenotypic variation, explained by genotypes, indicated that the genotypes were diverse and a major part of variation in heading date and spike length resulted from genetic effect.

Keywords: Barley (Hordeum vulgare L.), grain yield, correlation, regression, analysis of variance

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Variation factors of milk yield and milk quality at SMADEA farm - Bousselem

Étude des facteurs de variation de la production laitière et de la qualité du lait dans la ferme SMADEA - Bousselem




1High Institute of Agriculture Chott-Meriam Sousse Tunisia


Abstract – Factors of variation of milk production and milk quality were studied at MARJA's agricultural and livestock Development Company, at Boussalem delegation, for three consecutive years in 2014, 2015 and 2016. The study used the analyses results of 1945 milk samples from Holstein cows with calving spread throughout the control periods. Findings showed that calving season, lactation number, lactation stage and relative humidity significantly affected individual milk quantities. The highest milk yield was recorded for lactations starting in winter and during moderately wet periods. The physico-chemical quality of controlled animals' milk was influenced mainly by lactation stage and control season. Indeed, winter periods were characterized by milks of better quality than other periods of the year. In addition, quality has evolved in the same way as the lactation period. Temperature effect assessment showed that mean fat and protein contents decreased with increasing Temperature-Humidity index. Somatic cell count was significantly affected by control season, lactation number and lactation stage. In fact, this cell count increased considerably in multiparous and at the same time as the lactation stage progressed.

Keywords: Milk production, factors of variation, milk quality, somatic cell count, physiological stage

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This article is published under license to Journal of New Sciences. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

CC BY 4.0