Selection strategies of segregant soybean populations for resistance to Asian rust

Aliny Simony Ribeiro,José Francisco Ferraz De Toledo,Magno Antonio Patto Ramalho

doi:10.1590/s0100-204x2009001100012

Aliny Simony Ribeiro, José Francisco Ferraz De Toledo + Show 1 more

Open Access

https://doi.org/10.1590/s0100-204x2009001100012

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Abstract

The objective of this work was to identify the best selection strategies for the more promising parental combinations to obtain lines with good resistance to soybean Asian rust (Phakopsora pachyrhizi). Two experiments were carried out in the field during the 2006/2007 and 2007/2008 growing seasons, to determine the percentage of infected leaf area of individual plants of five parents and their segregant F2 and F3 populations. The data obtained indicates that additive genetic variance predominates in the control of soybean resistance to Asian rust, and that the year and time of assessment do not significantly influence the estimates of the genetic parameters obtained. The narrow-sense heritability (h²r) ranged from 23.12 to 55.83%, and indicates the possibility of successful selection of resistant individuals in the early generations of the breeding program. All the procedures used to select the most promising populations to generate superior inbred lines for resistance to P. pachyrhizi presented similar results and identified the BR01-18437 x BRS 232 population as the best for inbred line selection.

Highlights

Soybean Asian rust, caused by the Phakopsora pachyrhizi Syd. & P
When developing a breeding program for rust resistance, information on the genetic control of soybean resistance is essential, and some Brazilian reports are already available in the literature (Pierozzi, 2007; Ribeiro et al, 2007)
The parental materials for the experiments were derived from the referred inbred lines/commercial cultivars by random selection followed by multiplication of a single plant from each cultivar

Summary

Introduction

Soybean Asian rust, caused by the Phakopsora pachyrhizi Syd. & P. Soybean Asian rust, caused by the Phakopsora pachyrhizi Syd. Syd. fungus, has a high potential for crop damage by causing fast leaf yellowing and premature fall, preventing full pod filling. Since 2001, epidemics of the disease have been reported in practically all Brazilian soybean cropping areas. When developing a breeding program for rust resistance, information on the genetic control of soybean resistance is essential, and some Brazilian reports are already available in the literature (Pierozzi, 2007; Ribeiro et al, 2007).

Objectives

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Results