Barley breeding for quality improvement in Tunisia

This study was initiated to assess the effectiveness of three selection procedures applied in the early  segregating generations of barley crosses for quality traits. The selection procedures were pedigree selection (PS), bulk selection (BS) and single seed descent selection (SSD). Selection was operated in F2’s crosses. Field trials were conducted with 19 F3 crosses of barley in two different environments, a sub-humid  environment at Beja and a semi-arid one at Kef. Heading date (HD), thousand kernel weight (TKW), protein  content (PC), â-glucan content (BG) and husk percentage (HP) were evaluated. Data were subjected to an  additive main effects and multiplicative interaction (AMMI) model to determine the efficiency of each method of selection for the proper environment. The results show that the AMMI model generated predictive  optimizing selection method. The pedigree selection was more efficient in high input environment, while the bulk method was very effective for the selection of kernel weight in target environment.Key words: Additive main effect and multiplicative interaction (AMMI) model, Barley, breeding methods, efficiency of selection, quality traits

BIOCHEMICAL COMPOSITION AND NUTRITIONAL EVALUATION OF BARLEY RIHANE (HORDEUM VULGARE L.)

Background: Many experimental studies have suggested an important role for barley Rihane(BR)in the prevention of colon cancer and cardiovascular diseases. The objective of this study was to evaluate the physico-chemical properties and nutritional characterizations of BR compared to other varieties grown in Tunisia (Manel, Roho and Tej). Material and Methods: Total, insoluble and soluble dietary fiber(β-glucan),total protein, ash and some minerals of BR and Tunisian barley varieties were determined. Results: The results revealed that BR is good source of dietary fiber mainly β-glucan compared to the other varieties. This variety is a relatively rich source of phosphorous and potassium and it contains many important unsaturated fatty acids. BR has higher nutritional value than other varieties. Conclusion: Barley Rihane has significant nutritional characterizations compared to others Tunisian barleys varieties

Performance of Barley Lines Selected under Drought Stressed Conditions and Ultra-Low Density

Rainfall and temperature are unpredictable in Mediterranean environments, which result in irregular environmental conditions for crop growth and a critical source of uncertainty for farmers. In this study, selected barley lines for grain yield stability under drought stressed conditions and ultra-low plant density (Honeycomb design), were evaluated for agronomic performance in semi-arid areas (Kef and Mornag) compared to the source material. Results showed a significant effect of genotype and genotype×environment (G×E) interaction which indicate the existence of differences among genotypes for plasticity. Biological and grain yield ranged from 3.72 to 7.13 t/ha and 1.46 to 2.66 t/ha across environments with higher values in Kef compared to Mornag. Five high yielding selected lines outyield the original populations (IH17 and IH4-H4 from Imen, AH10-H2 and AH10-H3 from Ardhaoui and MH18 from Manel). The first cycle low yielding lines showed a performance that ranked below the source material. Second cycle high yielding lines did not differ from the first cycle high yielding ones. In conclusion, selection under ultra-low density has been proven an efficient tool to select for lines with high agronomic performance and improved adaptation under the Tunisian dry conditions

Effect of dietary fibre of barley variety 'Rihane' on azoxymethane-induced aberrant crypt foci development and on colonic microbiota diversity in rats.

International audienceMany epidemiological and experimental studies have suggested an important role for dietary fibre (DF) of cereals in the prevention of colon cancer. The objective of the present study was to explain the effects of the DF of barley Rihane (BR) on azoxymethane (AOM)-induced aberrant crypt foci (ACF) and colonic bacterial diversity in rats. Following an acclimatisation period, rats were divided into four groups and fed a control (C) diet or experimental diet containing 30 % of BR. DF content in the experimental diet was twice that of the C diet (total DF was 8*69 % in the C diet and 15*24 % in the BR diet). At 7 and 8 weeks of age, rats received two successive subcutaneous injections of AOM at 20 mg/kg body weight. At 12 weeks after the first injection, ten animals from each group were killed. The BR diet decreased colonic pH (P < 0*05) compared with the C diet. The total number of ACF observed decreased considerably in the BR/AOM group compared with the C/AOM group (P < 0*05). Comparison of similarity coefficients showed variability of colonic microbiota species between the different groups. In addition, we showed inter-individual variability within the same group. This similarity was affected by BR and AOM. The present results show that bifidobacteria numbers were lower in rats fed the BR diet compared with those fed the C diet. However, the number of enterobacteria in colonic content was increased (P < 0*05) in the BR group compared with the C group. The results from the present study show that the DF of BR reduced the incidence of AOM-induced ACF and increased microbiota biodiversity

Physiological and biochemical parameters: new tools to screen barley root exudates allelopathic potential (*Hordeum vulgare* L. subsp. *vulgare*

peer reviewedMorphological markers/traits are often used in the detection of allelopathic stress, but optical signals including chlorophyll a fluorescence emission could be useful in developing new screening techniques. In this context, the allelopathic effect of barley (Hordeum vulgare subsp. vulgare) root exudates (three modern varieties and three landraces) were assessed on the morphological (root and shoot length, biomass accumulation), physiological (Fv/Fm and F0), and biochemical (chlorophyll and protein contents) variables of great brome (Bromus diandrus Roth., syn. Bromus rigidus Roth. subsp. gussonii Parl.). All the measured traits were affected when great brome was grown in a soil substrate in which barley plants had previously developed for 30 days before being removed. The response of receiver plants was affected by treatment with activated charcoal, dependent on barley genotype and on the nature of the growing substrate. The inhibitory effect was lower with the addition of the activated charcoal suggesting the release of putative allelochemicals from barley roots into the soil. The barley landraces were more toxic than modern varieties and their effect was more pronounced in sandy substrate than in silty clay sand substrate. In our investigation, the chlorophyll content and Fv/Fm were the most correlated variables with barley allelopathic potential. These two parameters might be considered as effective tools to quantify susceptibility to allelochemical inhibitors in higher plants