Submitted by (edna.saturno@ufrpe.br) on 2017-04-10T12:56:37Z No. of bitstreams: 1 Eduardo Bruno Afonso Ferreira Pita.pdf: 590172 bytes, checksum: af018845d1a00ba8cf2281a306b684a5 (MD5) / Made available in DSpace on 2017-04-10T12:56:37Z (GMT). No. of bitstreams: 1 Eduardo Bruno Afonso Ferreira Pita.pdf: 590172 bytes, checksum: af018845d1a00ba8cf2281a306b684a5 (MD5) Previous issue date: 2013-01-30 / The objective of this work were to select Pennisetum sp. genotypes based on survival and realize the characterization agronomic-bromatological in Serra Talhada municipality, semiarid region of Pernambuco. The experiment was established in 2011 at the Lauro Ramos Bezerra Experimental Station, Agricultural Research Institute (IPA), Northeast Brazil, under randomized block design, with four replications. The clones/treatments were represented by 38 Pennisetum sp. genotypes, being 27 elephant grass (P. purpureum Schum.) interspecific hybrids crossed with millet (P. glaucum L. R. Br.), generated in 2009; seven elephant grass cultivars (Taiwan A-146, Taiwan A-25, Mercker SEA, Cuba 116, “Elefante Roxo”, “Elefante B” and Napier 472-76); two commercial cultivars (Cameroon and “Mineirão”) and two elephant grass interspecific hybrids with millet from the IPA Itambé-PE unity (Itambé-2006 selection and Natural Itambé). Ten agronomic-bromatological traits were evaluated in three cycles between the months of February/2011 to March/2012, with the first cut made after 60 days and the other with 105 days, because of the dry season. Of the 38 genotypes evaluated, eight elephant grass cultivars (“Elefante Roxo”, Taiwan A-146, Cuba 116, Taiwan A-25, Napier 472-76, “Elefante B”, “Mineirão” and Cameroon) and eight interspecific hybrids (ST-20A, ST-36A, ST-42, ST-45A, ST-51, Seleção Itambé-2006 e Natural Itambé) were selected . The cultivars presented higher survivability compared to hybrids in the Serra Talhada conditions. However the some hybrids showed survivors, revealing expressive dry matter concentration and high production, highlighting the ST-36A, ST-42 and ST-47A hybrids, which showed 6.6, 4.2 and 5.5 t DM/ha and concentration of dry matter of 24.46, 25.95 and 23.15% on average of the three cuts, respectively. / Objetivou-se com esse trabalho selecionar genótipos de Pennisetum sp. com base na sobrevivência e realizar a caracterização agronômico-bromatológico no município de Serra Talhada, região semiárida de Pernambuco. O experimento foi implantado em 2011, na Estação Experimental Lauro Ramos Bezerra, pertencente ao Instituto Agronômico de Pernambuco (IPA), adotando-se o delineamento em blocos ao acaso, com quatro repetições. Os clones/tratamentos foram representados por 38 genótipos de Pennisetum sp., sendo 27 híbridos interespecíficos de capim-elefante (P. purpureum Schum.) cruzado com o milheto (P. glaucum L. R. Br.) gerados em 2009, sete cultivares de capim-elefante (Taiwan A-146, Taiwan A-25, Mercker SEA, Cuba 116, Elefante Roxo, Elefante B e Napier 472-76), dois cultivares comerciais (Cameroon e o Mineirão) e dois híbridos interespecíficos de capim-elefante com milheto oriundos da unidade do IPA de Itambé-PE (Seleção Itambé-2006 e o Natural Itambé). Dez variáveis agronômico-bromatológicas foram avaliadas em três ciclos compreendidos entre os meses de fevereiro de 2011 a março de 2012, sendo o primeiro corte realizado aos 60 dias e os demais com 105 dias, devido a estação seca. Dos 38 genótipos, oito cultivares de capim-elefante (Elefante Roxo, Taiwan A-146, Cuba 116, Taiwan A-25, Napier 472-76, Elefante B, Mineirão e o Cameroon) e oito híbridos interespecíficos (ST-20A, ST-36A, ST-42, ST-45A, ST-51, Seleção Itambé-2006 e Natural Itambé) foram selecionados. Os cultivares apresentou maior capacidade de sobrevivência frente aos híbridos nas condições de Serra Talhada, porém alguns híbridos se mostraram sobreviventes, revelando teores de matéria seca elevada e valores de produção expressivos, destacando-se o ST-36A, ST-42 e o ST-47A, que apresentaram 6,6; 4,2 e 5,5 t de MS/ha e teores de MS de 24,46 %, 25,95 % e 23,15 % na média dos três cortes, respectivamente.

De nombreuses bananes cultivées et consommées sont des hybrides interspécifiques triploïdes entre Musa acuminata (génome A) et Musa balbisiana (génome B). L'amélioration de ces cultivars nécessite de mettre en place des stratégies complexes liées à leur faible fertilité et leur niveau de ploïdie. De plus, le génome M. balbisiana porteur de caractères agronomiques intéressants est malheureusement porteur de séquences intégrées de Banana streak virus (ou eBSV pour endogenous BSV). Ces eBSV sont capables de produire, dans un contexte de croisements interspécifiques et sous conditions de stress abiotiques, des génomes viraux responsables de l'infection systémique du bananier. L'activation spontanée de ces eBSV est la contrainte majeure des programmes d'amélioration du bananier plantain depuis plus de 10 ans. La ségrégation des chromosomes A et B chez les clones polyploïdes interspécifiques de bananiers est encore très peu connue. Nous avons au cours de cette thèse analysé la recombinaison et la ségrégation chromosomique chez 184 plantes issues de la descendance AAAB (CRBP39) x AA (Pahang_Carbap) au moyen de 38 marqueurs SSR distribués sur les 11 chromosomes Musa et de 6 marqueurs PCR spécifiques des deux espèces BSV présentes chez CRBP39 (eBSGFV-7 et eBSOLV-1). Nous avons observé qu'au cours de la formation des gamètes chez l'allotétraploïde CRBP39, la plupart des marqueurs du tétraploïde AAAB CRBP39 ont une ségrégation de type tétrasomique et que les génomes A et B recombinent au niveau de tous les segments de chromosomes pour lesquels nous pouvions suivre les allèles du chromosome B. D'autre part, nous avons montré que 50% des descendants ont reçu, à un ou quelques loci, un ou trois allèles du parent AAAB (CRBP39) au lieu de deux. La composition allélique de ces gamètes aneuploïdes, la cartographie génétique et l'analyse des corrélations entre marqueurs suggèrent que cette particularité résulte d'une variation structurale entre génomes A et B. Un des chromosomes B correspondrait à une partie des chromosomes 1A et 3A. Nous avons également observé une distorsion de ségrégation des loci eBSV avec une surreprésentation d'individus possédant au moins une intégration eBSV (86%). La régulation des eBSV semble très complexe et nécessitera des études complémentaires pour tenter d'identifier le ou les facteurs génétiques impliqués. Finalement, notre travail a montré que des croisements de type AAAB x AA peuvent générer des plantes possédant du génome B sans aucune intégration BSV (13%). Ce résultat est important car il ouvre une voie de contournement à la contrainte eBSV dans les programmes d'amélioration génétique. / Many cultivated and consumed banana are interspecific triploid hybrids between Musa acuminata (A genome) and Musa balbisiana (B genome). The genetic improvement of these cultivars requires the implementation of complex breeding strategies due to their low fertility and ploidy level. In addition, the B genome of M. balbisiana which bears interesting agronomic traits unfortunately carries endogenous Banana streak virus sequences (eBSV). Under certain conditions such as interspecific crosses and abiotic stresses, these eBSV are able to produce infectious viral genomes responsible for systemic infection of banana. The spontaneous activation of these eBSV is the major constraint of plantains improvement programs for more than 10 years. The A and B chromosomes recombination and segregation in interspecific polyploids banana are still poorly understood. We here analyzed chromosomes recombination and segregation in 184 offspring from the cross AAAB (CRBP39) x AA (Pahang_Carbap) using 38 SSR markers distributed on the 11 Musa chromosomes and 6 specific PCR markers of both BSV species integrated in CRBP39 (eBSGFV-7 and eBSOLV-1). We noticed that during CRBP39 meiosis most of the SSR markers have tetrasomic segregation and that A and B genomes recombine at all chromosomes segments where we were able to follow chromosome B alleles. Besides, we showed that 50% of the offspring received at one or several loci, one or three alleles of the CRBP39 parent instead of two. The allelic composition of these aneuploid gametes, the genetic map and the analysis of correlations between markers suggest that this peculiar observation is due to a structural variation between A and B genomes. One of the B chromosomes would be part of chromosomes 1A and 3A. We also noticed a distorted segregation of eBSV loci with an overrepresentation of individuals harboring at least one of the eBSV (86%). eBSV regulation seems very complex and requires additional studies to identify the genetic factor(s) involved. Finally, we also showed that AAAB x AA crosses can generate plants with B genome but without eBSV. This is the case for 13% of the offspring. This result is important because it shows that we can overcome eBSV constraint in banana breeding programs.

Introgression of genes from crops into ruderal populations is a multi-step process requiring sympatry, synchronous flowering, chromosomal compatibility, successful pollination and development of the zygote, germination, establishment and reproduction of hybrid progeny. The goal of this thesis was to generate data on as many steps in this process as possible and integrate them into a predictive statistical model to estimate the likelihood of successful introgression under a range of scenarios. Rape (Brassica napus) and wild turnip (B. rapa var. oleifera) were used as a model system. A homozygous dominant mutation in the rape genome conferring herbicide resistance provided a convenient marker for the study of introgression. Potential differences between wild turnip populations from a wide range of geographic locations in New Zealand were examined. Hand pollination established the genetic compatibility of rape and wild turnip and a high potential for gene introgression from rape to wild turnip. Interspecific hybrids were easily generated using wild turnip as the maternal plant, with some minor differences between wild turnip populations. The frequency of successful hybridisation between the two species was higher on the lower raceme. However, the upper raceme produced more dormant interspecific hybrid seed. Field trials, designed to imitate rare rape crop escapes into the ruderal environment, examined the ability of rare rape plants to pollinate wild turnip plants over four summers. At a ratio of 1 rape plant for every 400 wild turnip plants, the incidence of interspecific hybridisation was consistently low (<0.1 to 2.1 % of total seed on wild turnip plants). There was a significant year effect with the first season producing significantly more seed and a greater frequency of interspecific hybrid progeny than the other years. The frequency of interspecific hybrid progeny increases when the ratio of rape: wild turnip plant numbers increases. The relative importance of anemophily and entomophily in the production of interspecific hybrids was examined. Wild turnip plants produced twice as many seeds with bee pollination relative to wind pollination. However, the frequency of interspecific hybrids under wind pollination was nearly twice that for bee pollination. Light reflectance patterns under UV light revealed a marked difference between wild turnip and rape flowers compared to near identical appearance under visible light. The data indicates that bees are able to distinguish between rape and wild turnip flowers and exhibit floral constancy when foraging among populations with these two species. Hybrid survival in the seed bank, germination and seedling establishment in the field are important components of fitness. Seed banks established in the soil after the field trials described above germinated in subsequent spring seasons. The predominantly brassica weed populations were screened for herbicide resistance and the numbers of interspecific hybrids germinating compared to the original frequency in the field trial results. Frequency of interspecific hybrids was reduced in the populations compared to the original seed deposit. Seed with a known frequency of interspecific hybrid seed was sown in a separate trial, and the frequency of interspecific hybrids compared at 0, 4, 6, and 8 weeks after sowing. Poor germination resulted limited competition between seedlings, however the frequency of interspecific hybrids declined over time indicating low plant fitness. There were no significant population effects on any parameters tested. Interspecific hybrids grown in a glasshouse were backcrossed to the parental species and selfed within the plant and within populations. Pollen from the interspecific hybrids was found to have markedly reduced fertility. Interspecific hybrid plants had low female fertility, with the majority (88%) of the pollinated flowers aborting the siliques. Of the remaining siliques, most (98%) had only one to three seeds per silique. Inheritance of the herbicide resistance gene was regular in backcrosses but highly skewed following self pollination with an excess of herbicide-sensitive progeny. Production of a stochastic predictive model integrated the information acquired over the practical work phase of this thesis and utilised the capabilities of @risk, a new application of a risk analysis tool. The three outputs examined were the number of flowering plants resulting from backcrosses to rape and wild turnip and self pollination of the interspecific hybrid progeny. Five scenarios were modelled and all demonstrated the high likelihood of introgression failure in this system. In all scenarios, >75% of simulations resulted in no interspecific hybrid progeny surviving to flowering in the third generation. In all scenarios, and for all three outputs, the seed set on the interspecific hybrids of the second generation was the major factor that limited the number interspecific hybrid progeny surviving to flowering in the third generation.