New soybean (Glycine max Fabales, Fabaceae) sources of qualitative genetic resistance to Asian soybean rust caused by Phakopsora pachyrhizi (Uredinales, Phakopsoraceae)

Pedro Henrique Braga Pierozzi,Wilmar Ferreira Lima,Carlos Alberto Arrabal Arias,Larissa Di Cássia Laperuta,José Francisco Ferraz De Toledo,José Ubirajara Vieira Moreira,Breno Francovig Rachid,Aliny Simony Ribeiro,Marcelo Fernandes De Oliveira

doi:10.1590/s1415-47572008000300018

Pedro Henrique Braga Pierozzi, Wilmar Ferreira Lima + Show 7 more

Open Access

https://doi.org/10.1590/s1415-47572008000300018

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Abstract

Asian soybean rust (ASR), caused by the phytopathogenic fungi Phakopsora pachyrhizi, has caused large reductions in soybean (Glycine max) yield in most locations in Brazil where it has occurred since it was first reported in May 2001. Primary efforts to combat the disease involve the development of resistant cultivars, and four dominant major genes (Rpp1, Rpp2, Rpp3 and Rpp4) controlling resistance to ASR have been reported in the literature. To develop new long-lasting soybean ASR resistance genes, we used field experiments to assess ASR leaf lesion type in 11 soybean genotypes (BR01-18437, BRS 184, BRS 231, BRS 232, BRSGO Chapadões, DM 339, Embrapa 48, PI 200487, PI 230970, PI 459025-A and PI 200526) and the 55 F2 generations derived from their biparental diallel crosses. The results indicated that PI 200487 and PI 200526 carry different dominant resistance major genes which are both different from Rpp2 through Rpp4. Furthermore, resistance to ASR in BR01-18437 is controlled by a single recessive major gene, also different from Rpp1 through Rpp4 and different from the genes in PI 200487 and PI 200526.

Highlights

IntroductionAsian soybean rust (ASR), caused by the phytopathogenic fungus Phakopsora pachyrhizi, has resulted in considerable yield losses since its detection in Brazil and has provoked great concern to both researchers and farmers
Asian soybean rust (ASR), caused by the phytopathogenic fungus Phakopsora pachyrhizi, has resulted in considerable yield losses since its detection in Brazil and has provoked great concern to both researchers and farmers. This disease was confirmed on the American continent in Paraguay on March 5th 2001 and on May 26th of the same year was detected in the Brazilian state of Paraná from the towns of Foz do Iguassu to Guaíra in the western region and the city of Londrina (Yorinori et al, 2005), spreading to all the main Brazilian soybean (Glycine max) cropping regions over the two growing seasons
Merrill) parental genotypes selected for study were one advanced breeding line (BR01-18437), six Brazilian commercial cultivars (BRS 184, BRS 231, BRS 232, BRSGO Chapadões, DM 339 and Embrapa 48) and four accessions from the Brazilian National Soybean Research Center ‘Embrapa Soybean’ Germplasm Bank (PI 200487, plant introductions (PIs) 230970, PI 459025-A and PI 200526), which had previously been identified as sources of ASR resistance genes

Summary

Introduction

Asian soybean rust (ASR), caused by the phytopathogenic fungus Phakopsora pachyrhizi, has resulted in considerable yield losses since its detection in Brazil and has provoked great concern to both researchers and farmers. This disease was confirmed on the American continent in Paraguay on March 5th 2001 and on May 26th of the same year was detected in the Brazilian state of Paraná from the towns of Foz do Iguassu to Guaíra in the western region and the city of Londrina (Yorinori et al, 2005), spreading to all the main Brazilian soybean (Glycine max) cropping regions over the two growing seasons. The objective of the study described in this paper was to identify of new sources of resistance to P. pachyrhizi because such sources are essential for the development of soybean cultivars resistant to ASR

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