Orientador: Antonio Ismael Inácio Cardoso / Banca: Noberto da Silva / Banca: Cyro Paulino da Costa / Abstract: The objective of this work was evaluate the inbreeding depression with successive generations of self-pollination in a cucumber "caipira" population (S0, S1, S2, S3; S4 e S5), obtained by crossing Safira x Hatem hybrids. Two experiments were accomplished: one to evaluate immature fruits production and another to analyze the mature fruits production, seed quality and yield. The experimental design of both experiments were randomized blocks, in the first with seven treatments (different generations of self pollination - S0 to S5 and the hybrid Safira), six replicates and five plants per plot and in the second the same seven treatments, four replicates and five plants per plot. In the first experiment (immature fruits) was number of leaves, length of the main stem, number and weight of fruits, total and commercial, number of nodes and vines percentage were evaluated. In the second experiment (mature fruit) the following traits were evaluated characteristic: seed number and weight per plant and per fruit and seed quality (germination test, first counted of seeds, index of germination speed and weight of 100 seeds). The averages were compared by the Tukey test (5%) and the evaluation of the inbreeding depression was made with regression analysis. In the experiment 1 smaller production of fruits was observed (total and commercial) starting from population S2, demonstrating possible vigor loss. The populations S0 and S1 were similar or superiors for the characteristics number of total fruits, total weight per plant and commercial weight per plant when compared to the hybrid Safira, demonstrating the potencial of this population to obtain a new cultivar or hybrid of the "caipira" type. The experiment two there was no statistical difference for all the appraised characteristics, showing that the inbreeding didn't affect the production and quality of the seeds in this population. / Mestre

Orientador: Antonio Ismael Inácio Cardoso / Banca: Noberto da Silva / Banca: Keigo Minami / Resumo: Foram conduzidos dois experimentos na FCA/UNESP, objetivando avaliar a depressão causada por endogamia com sucessivas gerações de autofecundação em uma população de pepino do tipo japonês. No primeiro experimento foram avaliadas características de produção de frutos imaturos no período de 21/08/2002 à 29/11/2002 em ambiente protegido. No segundo experimento foram avaliadas características de produção e qualidade de sementes no período de 12/03/2003 à 13/06/2003 em condições de campo. A partir do intercruzamento entre plantas do híbrido Natsu suzumi foi obtida a geração F2, considerada como população S0. Obtiveram-se progênies S1, S2, S3, S4 e S5, através de autofecundações sucessivas pelo método do SSD ('Single Seed Descent'). Ao partir da mistura ao acaso de sementes de progênies com igual número de autofecundações sucessivas foram obtidas cinco populações denominadas de população S1 a população S5. Foram sete tratamentos (híbrido Natsu suzumi, populações S0 a S5) e o delineamento experimental foi em blocos ao acaso, com seis e quatro repetições no primeiro e segundo experimento, respectivamente e cinco plantas por parcela nos dois experimentos. No primeiro experimento (frutos imaturos) foram avaliados, número de folhas, comprimento da haste principal, número e massa de frutos, total e comercial, número de nós e porcentagem de brotações. No segundo experimento (frutos maduros) avaliaram-se características relacionadas com produção (número e massa de sementes por planta e por fruto) e qualidade de sementes (teste padrão de germinação, primeira contagem de sementes, índice de velocidade de germinação, massa de 100 sementes). Foram realizadas as análises de variância para cada característica, e as médias dos tratamentos foram comparadas pelo teste de Tukey (%). Também foram realizados análises de variância apenas com as seis... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Two experiments were set up at FCA/UNESP. The objective of this work was to evaluate the inbreeding depression with successive generations of self pollination in a cucumber Japanese population. It was studied one population F2 obtained from a commercial hybrid (Natsu suzumi) considered as S0 population. In the first experiment were appraised characteristics of production of immature fruits in the period of 21/08/2002 to 29/11/2002 in protected cultivation. In the second experiment were appraised seed production and quality in the period of 12/03/2003 to 13/06/2003 in open field conditions. It was obtained progenies S1, S2, S3, S4 and S5 through the 'Single Seed Descent' methodology. It was used randomized blocks with seven treatments (different generations of self pollination - S0 to S5 and the hybrid Natsu suzumi) six and four replicates in the first and second experiment and five plants per plot in both. In the first experiment (immature fruits) were evaluated number of leaves, length of the main stem, number and weight of fruits, total and commercial, number of nodes and vines percentage. In the second experiment (mature fruit) characteristic related with production were evaluated (number and weight of seeds per plant and per fruit) and quality of seeds (germination test, first counted of seeds, index of germination speed and weight of 100 seeds). The variance analyses were accomplished each characteristic and the averages of the treatments were compared by the test of Tukey (%). Also accomplished just with the six inbreed generations to evaluate the possible inbreeding depression (without including the commercial hybrid). In the comparison among the population differences were not observed for the characteristics appraised showing there were not production loss for inbreeding in this population. However, for the characteristics length of the main stem, number of total fruit, weight of seeds per fruit and seed number per fruit the commercial. / Mestre

Resumo: A baixa freqüência de genes recessivos deletérios e letais e a grande proporção de locos favoráveis já fixados nos híbridos comerciais, associado a uma seleção fenotípica eficiente entre e dentro de linhagens pode permitir a obtenção de híbridos promissores. Em média, são gastos de 8 a 10 anos para que um novo híbrido chegue ao mercado, o que implica diretamente no custo final das sementes. Para reduzir esse tempo é interessante viabilizar a utilização de linhagens parcialmente endogâmicas nos cruzamentos para agilizar o processo de obtenção de híbridos superiores e reduzir os custos da produção de sementes híbridas. Diante da necessidade de identificar híbridos de destaque e de encontrar alternativas que conduzam à redução dos custos e do tempo para a obtenção de sementes híbridas, o objetivo desse trabalho foi avaliar o potencial de linhagens parcialmente endogâmicas de milho com três (S3) e quatro (S4) gerações de autofecundação, obtidas de híbridos simples comerciais, com relação à heterose dos híbridos resultantes / Abstract: The low frequency of deleterious recessive and lethal genes and the large proportion of favorable loci already set in commercial hybrids combined with an efficient phenotypic selection among and within strains may allow the achievement of promising lines. On average, spending 8 to 10 years for a new hybrid to reach the market, which directly implies the final cost of the seeds. To reduce this time it is interesting to enable the use of partly inbred lines at intersections to expedite the process of obtaining superior hybrids and reduce the costs of producing hybrid seeds. Faced with the need to identify hybrids highlighted and to find alternatives that lead to the reduction of costs and time required for the production of hybrid seeds, the purpose of this study was to evaluate the potential of partly inbred lines of maize with three (S3) and four (S4) generations of selfing, obtained from commercial single cross hybrids, with respect to the follow-on hybrid heterosis / Orientador: José Roberto Moro / Coorientador: Flávio Trevizoli Silveira / Banca: Herberte Pereira da Silva / Banca: Sandra Helena Unêda-Trevisoli / Mestre