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| Author(s): |
Celia Correia Malvas
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 1998-10-30 |
| Advisor: | Luis Eduardo Aranha Camargo |
| Abstract | |
RAPDs molecular markers previously located in the genetic map of Brassica oleracea were used to localize resistance genes to Xanthomonas campestris pv. campestris, causal agent of crucifer black rot, and to race 2 of Fusarium oxysporum f. sp. conglutinans, agent of fusarium wilt. The markers used to identify resistance genes to X. campestris pv. campestris were also used to detect genomic regions that control the morphological traits petal color and flowering time. The Iinkage between these traits and resistance was also studied. For evaluation of resistance to X. campestris pv. campestris and morphological traits, 500 F2 seedlings originated from crosses between the resistante line Badger Inbred-16 and susceptible line fast cycling LC201 were used. For evaluation of resistance to race 2 of F. oxysporum f. sp. conglutinans, 3 progenies derived from a cross between the resistance line OSU Cr-7 and LC201 were used. Resistance to X. campestris pv. campestris was evaluated by inoculation of quaternary expanded leaves and assessment of lesion area plotted in a distribution curve. Then 56 plants were selected from each extreme of the phenotypic distribution curve, which were evaluated for morphological traits. For resistance evaluation to race 2 of F. oxysporum f. sp. conglutinans, seedling roots were inoculated and they were classified in resistante or susceptible by presence or absence of disease symptons, repectively. The statistical analyses used to detect association among traits and genotype in the locus marker were performed by the Mann Whitney U test for X. campestris pv. campestris and by analysis of variance to F. oxysporum f. sp. conglutinans. In the analyses for X. campestris pv. campestris, association were found among six locus markers and QRLs, and among two markers and the traits flowering time and petal color. It was also detected a linkage between the trait petal color and resistance. A correlation test used to verify the linkage among markers, detected two linked marker groups detecting different QRLs. Association were not found among resistance genes to race 2 of F. oxysporum f. sp. conglutinans and markers and resistance gene to race 1 (AU) | |