Introgresión acelerada de resistencia al nematodo del quiste de la soja mediante retrocruzamiento asistido por marcadores de polimorfismos de nucleótido simple
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Date
2016
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Facultad de Ciencias Agrarias. Universidad Nacional de Rosario
Abstract
El Nemátodo del Quiste de la Soja (NQS), cuyo agente causal es Heterodera glycines, es
una de las enfermedades más destructivas de la soja a nivel mundial. El uso de cultivares
resistentes es la vía más efectiva y económica de controlar la enfermedad. El método de la
retrocruza (RC) es el más empleado para la incorporación de genes de resistencia a germoplasma
elite. Sin embargo, la necesidad de realizar al menos seis o siete generaciones para recuperar el
genotipo del progenitor recurrente (PR) desalienta la utilización de esta técnica. La selección
asistida por marcadores moleculares (SAM) contribuye a facilitar la recuperación del genoma del
PR en un menor número de generaciones. El objetivo del presente estudio fue la recuperación
rápida del genoma del PR utilizando la SAM en generaciones tempranas, en un programa de
retrocruzas orientado a la incorporación de un locus de resistencia a H. glycines. Los parentales
fueron evaluados con 550 marcadores de polimorfismo de nucleótido simples (SNP),
uniformemente distribuidos en los 20 cromosomas de la soja. Los SNPs que resultaron
polimórficos fueron luego usados para caracterizar las plantas segregantes en las generaciones
RC1F1, RC2F1 y RC2F2. La SAM permitió identificar plantas 100% similares al PR, para el
conjunto de los SNPs evaluados, en la generación RC2F2, para una de las cruzas evaluadas. La
aplicación de la SAM permitió recuperar el genoma del PR en dos RC, reduciendo en dos tercios
(i.e. de seis a dos) el número de RC necesarias para recuperar el genoma del PR, en un programa
de mejoramiento orientado a la incorporación de resistencia al NQS en germoplasma elite de
soja.
The soybean cyst nematode (Heterodera glycines) is one of the most destructive soybean diseases worldwide. The use of resistant cultivars is the most effective and economical way to control the disease. The backcross (BC) is the most useful method to incorporate resistance genes to elite germplasm. However, the six to seven generations required for achieving the goal result in a low adoption of backcrossing. The marker-assisted selection (MAS) contributes to facilitate the recovery of the recurrent parent (RP) genome in few generations. The aim of this study was the recovery of the RP genome using MAS in early generations of a backcrossing program aimed to incorporate a resistance locus to H. glycines. The parental genotypes were evaluated with 550 single nucleotide polymorphism (SNP) markers, evenly distributed on the 20 soybean chromosomes. Polymorphic SNP were then used to characterize segregant plants in the BC1F1, BC2F1 and BC2F2 generations. By using SNP markers it was possible to identify the plants 100 % similar to the RP for the SNPs evaluated in the BC2F2 generation in one of the two crosses tested. The implementation of MAS in the backcrossing program allowed the recovery of the RP genome in two BC generations, reducing in two-thirds (i.e. from six to two) the time required for incorporating resistance to soybean cyst nematode to elite soybean germplasm.
The soybean cyst nematode (Heterodera glycines) is one of the most destructive soybean diseases worldwide. The use of resistant cultivars is the most effective and economical way to control the disease. The backcross (BC) is the most useful method to incorporate resistance genes to elite germplasm. However, the six to seven generations required for achieving the goal result in a low adoption of backcrossing. The marker-assisted selection (MAS) contributes to facilitate the recovery of the recurrent parent (RP) genome in few generations. The aim of this study was the recovery of the RP genome using MAS in early generations of a backcrossing program aimed to incorporate a resistance locus to H. glycines. The parental genotypes were evaluated with 550 single nucleotide polymorphism (SNP) markers, evenly distributed on the 20 soybean chromosomes. Polymorphic SNP were then used to characterize segregant plants in the BC1F1, BC2F1 and BC2F2 generations. By using SNP markers it was possible to identify the plants 100 % similar to the RP for the SNPs evaluated in the BC2F2 generation in one of the two crosses tested. The implementation of MAS in the backcrossing program allowed the recovery of the RP genome in two BC generations, reducing in two-thirds (i.e. from six to two) the time required for incorporating resistance to soybean cyst nematode to elite soybean germplasm.
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Keywords
Marcadores moleculares, Marcadores genéticos, Retrocruzamiento, Soja, Genes, Fitomejoramiento