Análisis de la merma de rendimiento de la línea A de maíz (Zea maize L.) en su versión HP asistido por marcadores moleculares
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2014
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La versión HP de la línea A presenta una merma de rendimiento bajo condiciones de estrés cuando se la compara con la versión no transgénica. La versión HR de la línea A no presenta este fenómeno. Para poder encontrar los fragmentos cromosómicos responsables y obtener una nueva línea sin la merma, la línea A HR se cruzó con la línea A HP asumiendo que las progenies eran líneas casi isogénicas (NILs) que diferían en unos pocos genes que podrían explicar la merma. Estas líneas fueron sembradas en el campo en dos ambientes. De acuerdo a los resultados de rendimiento, fueron seleccionadas las 10 mejores y las 10 peores líneas. Los parentales fueron secuenciados y como resultado se seleccionaron algunos SNPs para genotipificar las 20 NILs. A partir de la secuenciación se observó que la línea A HR tenía muchas nuevas regiones que eran diferentes a ambas versiones de la línea A: tanto convencional como HP. No se observaron diferencias alélicas entre las 10 mejores y las 10 peores NILs (o fragmentos candidatos) que pudiesen explicar la merma en rendimiento. La similitud entre las versiones HP y HR en el cromosoma dos (donde está inserto en evento TC1507) sugiere que la merma no es causada por arrastre de ligamiento. Sin embargo, el arrastre por ligamiento no puede ser descartado ya que otros fragmentos presentes en la versión HR en otras regiones genómicas podrían estar compensando la perdida. Fue encontrada una versión HP con un mayor rendimiento pero no los fragmentos candidatos.
The HP version of the line A shows a yield loss under stressful conditions when compared to the non transgenic version. The line A HR does not show this issue. So as to be able to find the chromosomal pieces responsible and to obtain a new HP version without the loss, the line A HR was crossed with the line A HP assuming that the progenies were near isogenic lines (NILs) differing only is some genes that could explain the yield loss. They were planted in the field in two environments. According to the yield performance, the ten best and the ten worst NILs were selected. The parents were sequenced and as a result some SNPs were selected to genotype the 20 NILs. It was observed that the HR version had a lot of new regions, different to both HP and conventional line A. Not allelic differences (or candidate fragments) were found between the best and the worst NILs that could explain the yield loss. The similarity between HP and HR version in chromosome two (where TC1507 is inserted) suggests that the yield is not caused by linkage drag. However, the linkage drag cannot be discarded since other fragments present in the HR version in other genomic regions could be compensating the loss. An HP version with higher yield was found but not the candidate fragments.
The HP version of the line A shows a yield loss under stressful conditions when compared to the non transgenic version. The line A HR does not show this issue. So as to be able to find the chromosomal pieces responsible and to obtain a new HP version without the loss, the line A HR was crossed with the line A HP assuming that the progenies were near isogenic lines (NILs) differing only is some genes that could explain the yield loss. They were planted in the field in two environments. According to the yield performance, the ten best and the ten worst NILs were selected. The parents were sequenced and as a result some SNPs were selected to genotype the 20 NILs. It was observed that the HR version had a lot of new regions, different to both HP and conventional line A. Not allelic differences (or candidate fragments) were found between the best and the worst NILs that could explain the yield loss. The similarity between HP and HR version in chromosome two (where TC1507 is inserted) suggests that the yield is not caused by linkage drag. However, the linkage drag cannot be discarded since other fragments present in the HR version in other genomic regions could be compensating the loss. An HP version with higher yield was found but not the candidate fragments.
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Maíz, Rendimiento de cultivos, Zea mays, Marcadores moleculares