A pesquisa teve como objetivo avaliar a possibilidade de obtenção de segregantes transgressivos precoces e produtivos através de 12 cruzamentos envolvendo 6 parentais exóticos (Pella, Williams, Century, Maple Presto, Maple Amber e Maccall) com dois parentais adaptados (BR80-6989 e Primavera). Foram estudadas as 12 progênies F 2 em 12 experimentos delineados em blocos casualizados com quatro repetições. Foram avaliados os seguintes caracteres: número de dias para início de florescimento, número de dias para maturidade, altura da planta no florescimento, altura da planta na maturidade, acamamento, valor agronômico, produtividade de planta individual e produtividade de parcela. Os resultados permitiram as seguintes conclusões: a) os parentais possuem características complementares de interesse para o melhoramento; b) houve uma grande variação de heterose e heterobeltiose porém nem sempre as maiores médias estavam associadas as maiores variâncias; c) a avaliação das progênies F2 através da frequência de genótipos superiores, demonstrou a existência de segregantes transgressivos que reuniam simultaneamente a precocidade, altura adequada a colheita mecanizada e produtividade / This research aimed to evaluate the potential of crosses between exotic and adapted parents for development of transgressive segregates having high levels of earliness and seed yielding. Six exotics parents (Century, Maple Amber, Maple Presto, McCall, Pella and Williams) were chosen based on their earliness and seed yielding; such parents exhibited the disadvantage of to be very sensitives to photoperiodic variations. Two adapted parents (BR 80-6989 and Primavera) were chosen based on their small sensitivity to variation and high seed yielding. However, they exhibited lower earliness than necessary. In 1985, handled hibridizations were made to obtaining 12 crosses (six exotic x two adapted). Natural selfing originated the F 2, that were evaluated at 12 experiments establishe in randomized block design with four replications. The results allowed the following conclusions: a) the parents were significantly different them selves; consequently, complementary traits were combined in all crosses; b) a large heterosis and heterobeltiosis variation were found for all traits evaluated, however, the higher means were not always related to higher variances; c) the combination of high earliness from exotic parents with long-juvenile trait from adapted parents was a promissing strategy for development of transgressive segregates appropriated to rotation crop with sugarcane
| Identifer | oai:union.ndltd.org:usp.br/oai:teses.usp.br:tde-20181127-155216 |
| Date | 06 June 1990 |
| Creators | Hiromoto, Dario Minoru |
| Contributors | Vello, Natal Antonio |
| Publisher | Biblioteca Digitais de Teses e Dissertações da USP |
| Source Sets | Universidade de São Paulo |
| Language | Portuguese |
| Detected Language | English |
| Type | Dissertação de Mestrado |
| Format | application/pdf |
| Rights | Liberar o conteúdo para acesso público. |
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