M. Lamine*

A. Chebaane

A. Mliki

Laboratory of Plant Molecular Physiology, Biotechnology Centre of Borj-Cédria, BP 901, Hammam-Lif 2050, Tunisia.

Abstract - No available information is on the inter-relationship between Maltaise of Tunisia (Citrus sinensis L.) orange genotypes and their genetic background to enable their implication in appropriate germplasm management programs. Phylogenic relationships and genetic diversity in citrus are considered to be important in clarifying their genetic relationships, germplasm characterization and the registration of new varieties. Two molecular markers, RAPD and SSR, were used to evaluate genetic diversity of nineteen Tunisian sweet oranges genotypes. Genetic parameters consisted of effective alleles; observed and expected heterozygosity (Ho; He) and polymorphic information content (PIC) were calculated based on molecular data. The values of similarity coefficient obtained in SSR analysis ranged from 0,38 to 1,00 among the genotypes studied, while the same values ranged from 0.33 to 0.84 in RAPD analysis. A combined RAPD/SSR dendrogram grouped the 19 accessions into eleven clades with a coefficient of 0.60. Combined data of three markers showed higher genetic diversity than two SSR and RAPD markers. Dendrogram showed that all the accessions were discriminated with various degree of subclustering within the clusters. These results will have implications for Maltaise breeding and conservation.

Keywords: Tunisian Maltaise orange / RAPD / SSR / Genetic diversity.

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R. Baccouche ¹

S. Bedhiaf ¹

M. Haddad ²

B. Jemmali ³

¹ Institut National Agronomique de Tunisie.

² Fondation Nationale d’Amélioration de la race Chevaline, Tunisie.

³ Laboratoire ADIPARA, Département de la Production Animale, Ecole Supérieure d’Agriculture Mateur, Tunisie.

Abstract - The survey on 154 native cattle owners was conducted in North West Tunisia. Photo shots of each animal were made which allowed us to conduct a study of the phenotypic diversity of this population. Blood samples were collected and genetic diversity was studies based on 2 primers combinations. In this study, amplified fragment length polymorphism (AFLP) was used to detect within and among population genetic diversity. The polymorphism information content (PIC) was 0.31. The differentiation coefficient between populations (Gst) was 0.06. These results indicate that the main genetic variation was within the population (94%) and the remaining (6%) of the variation was among populations. The gene flow (Nm) was relatively high (7.56). These results translate the critical situation in which native cattle are encountered. Little genetic differences are met across ecotypes and the large amount of variation is found within population.

Keywords: population of cattle / genetic diversity / phenotypic variability / AFLP.

Résumé - L’objectif de cette étude est d’aborder la description des ressources génétiques bovines locales et de leurs conditions d’élevage. En effet, la population bovine locale est un modèle intéressant du fait de ses origines, de ses caractéristiques héritées, et des conditions d’élevage dans lesquelles elle s’est développée. Ainsi, les travaux menés se sont intéressés à la caractérisation phénotypique, à l’étude de la diversité génétique de cette population et des systèmes d’élevage utilisés. Afin de réaliser ces objectifs, un inventaire a été fait sur un effectif total de 154 bovins locaux, situés au Nord Ouest de la Tunisie. L’étude de la variabilité phénotypique a été fondée sur une description des caractères qualitatifs. Toutefois, cette variabilité n’est pas liée à la distribution géographique de ces derniers. L’étude moléculaire établie à l’aide du marqueur moléculaire dominant AFLP a révélé plusieurs caractéristiques importantes : La combinaison d’amorce E-AGG/M-CTT est plus spécifique (Rp= 69,5) à l’étude de la diversité génétique des populations bovines que celle E-ACT/M-CTT (Rp= 56,7). La population bovine locale présente une diversité génétique relativement faible. 94% de la diversité génétique totale est d’origine intra-population (entre individus). Le flux de gènes est très élevé (7,56). La population bovine locale est consanguine, et où 85% des individus sont similaires. Ceci implique qu’il s’agit d’une même race qui forme une population hétérogène sur le plan morphologique, la diversité génétique de cette race est entrain de disparaître.

Mots clés : population bovine / diversité génétique / variabilité phénotypique / AFLP.

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F. Mani *

C. Hannachi

Institut Supérieur Agronomique Chott Mariem. Laboratoire des Sciences Horticoles et de culture in vitro, Chott Mariem , Sousse, 4042, Tunisie

Abstract - The principal objective of this work is to explore intraspecific variability for yield and other parameters, and to determine some criteria to make selection species easy in early stage in programs of genetic improvement of yield of peas. To determine these concepts, many morphological parameters, composed of yield and its components, phenological parameters ,characteristics of leaf , parameters of growth, were studied on 12 lines of pea in two different environments : under greenhouse and in field. The results showed an important genetic variability between the genotypes for: Number of pods per plant, the phonological parameters, and the length of plant, the number of branches, the yield and its components and for the characteristics of leaf. The results of correlations and principal components analyses showed that the parameters : Number of grains by plant, height, biomass, length and surface of tendrils, date of levee and date of flowering, may be determinant criteria in an improving yield .

Keywords: Yield / phenological parameters / correlations / statistical analysis / Pea.

Résumé - L'objectif principal de ce travail est d'explorer la variabilité intraspécifique et de déterminer les critères de selection a utiliser dans les programmes d'amélioration génétique du rendement de pois. Pour déterminer ces critères, plusieurs paramètres morphologiques, des paramètres phénologiques,des paramètres de croissance, ont été étudiés sur douze variétés de pois dans deux environnements différents: sous serre et en plein champ. Les résultats ont montré une grande variabilité génétique entre les génotypes pour: le nombre de gousses par plante, les paramètres phénologiques, la longueur de la plante, le nombre de branches, le rendement et ses composantes ainsi que pour les caractéristiques de la feuille. Les résultats d’analyse de corrélations et composantes principales ont montré que les paramètres: Nombre de grains par plante, la hauteur, la biomasse, la longueur et la surface de vrilles, la date de levée et la date de la floraison, peuvent être déterminants dans les critères de selection des hauts rendements.

Mots Clés: Rendement / paramèters phénologiques / correlations / analyses statistiques / pois.

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S. Soufi ^*

S. Rezgui

T. Bettaeib

Laboratoire des Sciences Horticoles, Institut National Agronomique de Tunisie (INAT), 43, Avenue Charles Nicolle 1082 -Tunis- Mahrajène TUNISIE

Abstract - The effect of exogenous application of hydrogen peroxide (H₂O₂), salicylic acid (SA), calcium chloride (CaCl₂) and 6-benzylaminopurine (BAP) on Stevia (Stevia rebaudiana Bert.) exposed to day night temperature (10/6°C) in a growth chamber for 120h was investigated. There was a positive physiological effect on growth and development of chilling-stressed seedlings by these compounds as shown by a higher dry weight and leaf mass area, electron transport rate (ETR) and quantum photosynthetic yield (Y) and both chlorophyll and carotenoid contents remains higher during exposure to low temperature in pretreated plants in comparison with control plants suggested that these compounds may improve the chilling tolerance of Stevia.

Keywords: Stevia / cold stress / signaling compounds / physiology / photosynthetic yield.

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L.O. Ojedapo* ¹,

S.R Amao ²

O.O. Ogunsola ³

¹Department of Animal Nutrition and Biotechnology, P.M.B 4000. Ladoke Akintola University of Technology. Ogbomoso. Oyo State. Nigeria.

²Department of Agricultural Education (Animal Sci. Division; Animal Breeding and Genetics unit), School of Vocational and Technical Education, P.M.B.1010, Emmanuel Alayande College of Education. Oyo .Oyo State. Nigeria.

³Department of Animal Production and Health, P.M.B 4000. Ladoke Akintola University of Technology. Ogbomoso. Oyo State. Nigeria.

Abstract - The experiment was conducted to compare the various carcass characteristics between two broiler strains. A total bird of 150 day-old chick of two commercial broiler strains (Marshall and Cobb, 75 each) were raised and at the end of 4, 6 and 8 weeks, 20 birds/strain; 40 birds/week, making a total of 120 birds were randomly selected from both strains for carcass analysis. The birds were starved of feed overnight and individually weighed to obtain starved live body weight. The birds were stunned and bled by severing the blood vessels and the nerve trunks at the roof of the mouth with a sticking knife. Thereafter, the birds were scalded, deplumed manually and eviscerated through a slit made between the end of the keel bone and rectum. Data were obtained on live weight (gram), eviscerated weight (gram), carcass weight (gram), dressing weight (gram), breast weight (gram), shank weight, thigh weight (gram), drumstick weight (gram) and back weight (gram). The visceral organs observed were liver, lungs, heart, kidney, spleen, gizzard, proventriculus and abdominal fats. At 4^th week of age, there were significantly differences in eviscerated weight (Cobb birds; 666,25g and Marshall birds; 578,90g), breast weight (Cobb birds; 176,75g and Marshall birds; 138,40g), gizzard weight (Cobb birds; 32,85g and Marshall birds; 29,25g) and abdominal fats (Cobb birds; 9,45g and Marshall birds; 7,80g) while Cobb birds were favoured. At the 6^th week of age; Cobb birds had higher values of live weight, eviscerated weight, carcass weight, dressing weight, breast weight, back weight, lungs, heart, abdominal fats and spleen than its Marshall counterpart. However, at the 8^th week of age; live weight for Cobb birds had higher values of 3005,60g, eviscerated weight (2264,00g), carcass weight (2088.80g), dressing weight (2634.55g), breast weight (727.05g), back weight (337.95g), lungs (17.10g) and heart (11.70g) than its counterpart Marshall birds. It can be concluded that the Cobb birds had a better carcass characteristics than the Marshall birds.

Keywords: Meat type chicken / genotype / age / carcass indices

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