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Analysis of the tolerance to Asian rust in partial diallel with transgenic and conventional soybean parents

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Felipe Maniero Nazato
Total Authors: 1
Document type: Master's Dissertation
Press: Piracicaba.
Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
Defense date:
Examining board members:
Natal Antonio Vello; Milena Moura de Araujo Biazuzo; Roberto Fritsche Neto
Advisor: Natal Antonio Vello

This research aimed to compare the performance of transgenic (RR soybean and management with glyphosate) and conventional (conventional soybean and herbicides) technologies for tolerance to rust (Phakopsora pachyrhizi ) and obtaining promising genotypes for seed yield and size (represented by the weight of one hundred seeds, PCS). A total of 200 progenies were evaluated in F2:5 and F2:6 generations; these progenies were obtained in two partial diallel 5 x 2, both involving five parents with high oil yield (USP 70.108, USP 70.010, USP 70.113, USP 70.007 and USP 70.042) in crosses with: (1) two elites conventional cultivars (BRS 133 and Conquista); (2) their essentially derived transgenic versions (BRS 245 RR and BRS Valiosa RR). The experiments involved: a) two managements with herbicides: conventional management for conventional soybean and management based in glyphosate herbicide to RR soybean; b) two managements with fungicides: an experiment with successive applications of Opera & Native (O&N, fungicides that control rust and late season leaf diseases, DFC), and another experiment with Derosal applications (fungicide that controls only DFC). The effect of rust for each genotype was expressed by the rate of reaction to rust on seed yield (FP) and on seed size (FT) as calculated from the differences in seed yield (PG) and seed size (PCS) between adjusted means in the two experiments with different fungicides. The soybean genotypes were compared by analysis of variance, multiple comparisons and parameter estimation of combining ability. In general, the control of rust with fungicides (O&N) resulted in higher means of PG and PCS. There was great variation among the effects of general and specific combining abilities, with major outstanding of USP 70.108, USP 70.010, and BRS 133 parents for PG and FP. The parent USP 70.042 was the most divergent and showed positive dominance for PG. Both technologies were numerically similar for FP and FT. The conventional technology has the advantage to be statistically more productive (PG and PCS) than transgenic technology. However, the transgenic technology has the advantage to be easier to use and less expensive to soybean producers. (AU)

FAPESP's process: 13/07152-0 - Partial diallel crosses for analysis of Asian rust tolerance between transgenic and conventional soybean
Grantee:Felipe Maniero Nazato
Support Opportunities: Scholarships in Brazil - Master