Variation of specific morphological traits and ploidy level of five "aegilops" l. species in Morocco

Variation of specific morphological traits and ploidy level of five Aegilops L. species in Morocco.The genus Aegilops L. represents an important natural source of useful genes for wheat breeding, with particular emphasis on biotic and abiotic stress resistance. For successful crosses, the primarily step is to select appropriate Aegilops accessions. In this paper, we studied five Moroccan species of an Aegilops collection on the basis of spike structure and chromosome number. Twenty-eight specific morphological characters were used to differentiate the species. Statistical analyses, in particular the DFA, allowed the characterization of the genetic variability of the species; the two first standardized axes explained 96,2% of the total variability and 100% of the entities were classified within their own group. In addition, the dendrogram constructed using morphological data reveals a significant variability within and between species. Cytogenetic study revealed four species, A. geniculata Roth, A. triuncialis L., A. ventricosa Tausch and A. peregrina Maire & Weiller, to be tetraploid. However, A. neglecta Req. ex. Bertol., where only two accessions are represented in the collection, revealed to be hexaploid, and can then be classified as A. neglecta subsp. recta Chennav

Genetics of resistance to Hessian fly (Mayetiola destructor) [Diptera : Cecidomyiida] biotype L in diploid wheat

La mouche de Hesse est un important ravageur de blé (Triticum spp.) et le biotype L de cette mouche est reconnu comme le plus virulent des biotypes connus. L'héritabilité de la résistance au biotype L de la mouche de Hesse a été étudiée à l'aide de croisements entre, d'une part, une lignée résistante de Triticum monococcum et, d'autre part, deux lignées sensibles de T. monococcum et une lignée sensible de T. boeoticum, tous des blés diploïdes. Les familles de plante F2 ou issues de rétrocroisements ont été évaluées au stade de semis par leur réaction à la mouche de Hesse et les ratios de ségrégation génétique des familles résistantes ou ségréguées par rapport aux familles sensibles ont été analysés par des tests d'ajustement du chi-carré. Il a été découvert que l'héritabilité est simple et sous le contrôle d'un ou deux gènes. Ceci est la première mention de l'héritabilité de la résistance à la mouche de Hesse chez les blés diploïdes de génome A et son contrôle génétique simple suggère la possibilité de transférer ce caractère aux blés cultivés.Hessian fly (Mayetiola destructor) is a serious pest of wheat (Triticum spp.) and of the reported biotypes of Hessian fly, biotype L is described as the most virulent. Inheritance of resistance to Hessian fly biotype L was investigated in crosses of a resistant accession of Triticum monococcum, and two susceptible accessions of T. monococcum and one susceptible accession of T. boeoticum, all diploid wheats. F2 and testeross (backeross) families were classified for reaction to Hessian fly in the seedling stage and analysed by Chi-square goodness-of-fit tests for genetic segregation ratios of resistant or segregating families to susceptible families. Resistance was found to be simply inherited, controlled by one or two genes. This is the first report on the inheritance of resistance to Hessian fly in A-genome diploid wheats, and simple genetic control indicates possibility of transfer of this trait to cultivated wheats

Physiological and photosynthetic response of quinoa to drought stress

Water shortage is a critical problem touching plant growth and yield in semi-arid areas, for instance the Mediterranean región. For this reason was studied the physiological basis of drought tolerance of a new, drought tolerant crop quinoa (Chenopodium quinoa Willd.) tested in Morocco in two successive seasons, subject to four irrigation treatments (100, 50, and 33%ETc, and rainfed). The chlorophyll a fluorescence transients were analyzed by the JIP-test to transíate stress-induced damage in these transients to changes in biophysical parameter's allowing quantification of the energy flow through the photosynthetic apparatus. Drought stress induced a significant decrease in the maximum quantum yield of primary photochemistry (Φpo = Fv/Fm), and the quantum yield of electron transport (Φeo). The amount of active Photosystem II (PSII) reaction centers (RC) per excited cross section (RC/CS) also decreased when exposed to the highest drought stress. The effective antenna size of active RCs (ABS/RC) increased and the effective dissipation per active reaction centers (DIo/RC) increased by increasing drought stress during the growth season in comparison to the control. However the performance index (PI), was a very sensitive indicator of the physiological status of plants. Leaf area index, leaf water potential and stomatal conductance decreased as the drought increased. These results indicate that, in quinoa leaf, JIP-test can be used as a sensitive method for measuring drought stress effects

Elevated genetic diversity in an F2:6 population of quinoa (<i>Chenopodium quinoa</i>) developed through an inter-ecotype cross

Quinoa (Chenopodium quinoa) is a seed crop of the Andean highlands and Araucanian coastal regions of South America that has recently expanded in use and production beyond its native range. This is largely due its superb nutritional value, consisting of protein that is rich in essential amino acids along with vitamins and minerals. Quinoa also presents a remarkable degree of tolerance to saline conditions, drought, and frost. The present study involved 72 F2:6 recombinant inbred lines (RIL) and parents developed through hybridization between highland (0654) and coastal (NL-6) germplasm groups. The purpose was to characterize the quinoa germplasm developed, to assess the discriminating potential of 21 agro-morpho phenological traits, and to evaluate the extent of genetic variability recovered through selfing. A vast amount of genetic variation was detected among the 72 lines evaluated for quantitative and qualitative traits. Impressive transgressive segregation was measured for seed yield (22.42 g/plant), while plant height and maturity had higher heritabilities (73 and 89%, respectively). Other notable characters segregating in the population included panicle and stem color, panicle form, and resistance to downy mildew. In the Principal Component analysis, the first axis explained 74% of the total variation and was correlated to plant height, panicle size, stem diameter, biomass, mildew reaction, maturation, and seed yield; those traits are relevant discriminatory characters. Yield correlated positively with panicle length and biomass. UPGMA based cluster analysis identified three groups: one consisting of late, mildew-resistant, high yielding lines; one having semi-late lines with intermediate yield and mildew susceptibility; and a third cluster consisting of early to semi-late accessions with low yield and mildew susceptibility. This study highlighted the extended diversity regenerated among the 72 accessions and helped to identify potentially adapted quinoa genotypes for production in the Moroccan coastal environment

Effet du nitrate d'argent sur les potentialités embryogènes des cals issus des embryons immatures de 17 cultivars de blé (Triticum aestivum L. et Triticum durum L.)

L'incorporation du nitrate d'argent (5mg/l) dans le milieu de culture des embryons zygotiques immatures de 17 cultivars de blé (Triticum durum L. et T. aestivum L.), a amélioré significativement les pourcentages d'induction de cals embryogènes et de régénération de plantules par cal. Le rendement en cals embryogènes a été multiplié par trois pour le cultivar «Cocorit» en présence de nitrate d'argent. La régénération de plantes à partir des cals initiés en présence d'AgN03 a été également 7 fois plus importante pour le cultivar &lt;&lt;1765&gt;&gt;. Cette régénération a, néanmoins, montré des variations importantes selon les génotypes testés. L'étude de la réponse in vitro des embryons immatures après quatre semaines de culture dans le milieu d'induction a permis de distinguer trois types de cals. Placés dans le milieu de différenciation, un type n'a régénéré que des racines alors que les deux autres ont régénéré des tiges et des racines

Characterization of Moroccan Aegilops spp. for germplasm enhancement

Le but de cet article est de d&eacute;crire la variation existante entre 149 accessions des esp&egrave;ces d&rsquo;Aegilops collect&eacute;es dans diff&eacute;rentes r&eacute;gions du Maroc, d'examiner la distribution des variations morphophysiologiques et de r&eacute;sistance, et de d&eacute;terminer la fr&eacute;quence des caract&egrave;res recherch&eacute;s parmi les esp&egrave;ces. Les donn&eacute;es pr&eacute;lev&eacute;es au cours des essais exp&eacute;rimentaux ont &eacute;t&eacute; analys&eacute;es &agrave; l&rsquo;aide de l&rsquo;analyse factorielle discriminante (DFA). Les trois premiers axes ont pu expliquer la totalit&eacute; de la variation (Pr&lt;5%). L&rsquo;estimation des distances de Mahalobis a montr&eacute; le rapprochement entre Ae. geniculata and Ae. triuncialis. La distribution des diff&eacute;rentes accessions dans de nouveaux groupes a montr&eacute; que 86,6% de celles-ci ont &eacute;t&eacute; affect&eacute;es dans leur propre esp&egrave;ce. Treize accessions d&rsquo;Ae. geniculata ont &eacute;t&eacute; plac&eacute;es dans le groupe d&rsquo;Ae. triuncialis confirmant le rapprochement entre ces deux esp&egrave;ces. La plus grande variation a &eacute;t&eacute; celle d&rsquo;Ae. geniculata pour les caract&egrave;res pr&eacute;cocit&eacute;, &eacute;talement et densit&eacute;. Aegilops ventricosa a &eacute;t&eacute; diff&eacute;renci&eacute;e des autres esp&egrave;ces par la longueur de ses feuilles, sa tol&eacute;rance pour la rouille foliaire et sa r&eacute;sistance &agrave; la c&eacute;cidomyie. La quatri&egrave;me esp&egrave;ce, Ae. neglecta a &eacute;t&eacute; la plus pr&eacute;coce et a combin&eacute; entre au moins trois types de r&eacute;sistance Les esp&egrave;ces spontan&eacute;es resteront dans le r&eacute;servoir g&eacute;n&eacute;tique universel pour l&rsquo;am&eacute;lioration v&eacute;g&eacute;tale. Elles doivent &ecirc;tre pr&eacute;serv&eacute;es pour une durabilit&eacute; des syst&egrave;mes de production

Variation of specific morphological traits and ploidy level of five "aegilops" l. species in Morocco

Variation of specific morphological traits and ploidy level of five Aegilops L. species in Morocco.The genus Aegilops L. represents an important natural source of useful genes for wheat breeding, with particular emphasis on biotic and abiotic stress resistance. For successful crosses, the primarily step is to select appropriate Aegilops accessions. In this paper, we studied five Moroccan species of an Aegilops collection on the basis of spike structure and chromosome number. Twenty-eight specific morphological characters were used to differentiate the species. Statistical analyses, in particular the DFA, allowed the characterization of the genetic variability of the species; the two first standardized axes explained 96,2% of the total variability and 100% of the entities were classified within their own group. In addition, the dendrogram constructed using morphological data reveals a significant variability within and between species. Cytogenetic study revealed four species, A. geniculata Roth, A. triuncialis L., A. ventricosa Tausch and A. peregrina Maire & Weiller, to be tetraploid. However, A. neglecta Req. ex. Bertol., where only two accessions are represented in the collection, revealed to be hexaploid, and can then be classified as A. neglecta subsp. recta Chennav