Genetic mapping of maize streak virus resistance from the Mascarene source. I. Resistance in line D211 and stability against different virus clones

Pernet, A and Hoisington, D A and et al, . (1999) Genetic mapping of maize streak virus resistance from the Mascarene source. I. Resistance in line D211 and stability against different virus clones. TAG Theoretical and Applied Genetics, 99 (3-4). pp. 524-539. ISSN 1432-2242

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Abstract

Maize streak virus (MSV) disease may cause significant grain yield reductions in maize in Africa. Réunion island maize germplasm is a proven source of strong resistance. Its genetic control was investigated using 123 RFLP markers in an F2 population of D211 (resistant) × B73 (susceptible). This population of 165 F2:3 families was carefully evaluated in Harare (Zimbabwe) and in Réunion. Artificial infestation was done with viruliferous leafhoppers. Each plant was rated weekly six times after infestation on a 1–9 scale previously adjusted by image analysis. QTL analyses were conducted for each scoring date, and for the areas under the disease, incidence and severity progress curves. The composite interval mapping method used allowed the estimation of the additive and dominance effects and QTL × environment interactions. Heritabilities ranged from 73% to 98%, increasing with time after infestation. Resistance to streak virus in D211 was provided by one region on chromosome 1, with a major effect, and four other regions on chromosomes 2, 3 (two regions) and 10, with moderate or minor effects. Overall, they explained 48–62% of the phenotypic variation for the different variables. On chromosome 3, one of the two regions seemed to be more involved in early resistance, whereas the second was detected at the latest scoring date. Other QTLs were found to be stable over time and across environments. Mild QTL × environment interactions were detected. Global gene action appeared to be partially dominant, in favor of resistance, except at the earliest scoring dates, where it was additive. From this population, 32 families were chosen, representing the whole range of susceptibility to MSV. They were tested in Réunion against three MSV clones, along with a co-inoculation of two of them. Virulence differences between clones were significant. There were genotype × clone interactions, and these were more marked for disease incidence than for severity. Although these interactions were not significant for the mean disease scores, it is suggested that breeders should select for completely resistant genotypes.

Item Type:	Article
Divisions:	UNSPECIFIED
CRP:	UNSPECIFIED
Uncontrolled Keywords:	Quantitative trait loci, Disease resistance, MSV, Composite interval mapping, Tropical maize
Subjects:	Others > Maize
Depositing User:	Mr Siva Shankar
Date Deposited:	15 Mar 2012 07:34
Last Modified:	15 Mar 2012 07:46
URI:	http://oar.icrisat.org/id/eprint/5720
Official URL:	http://dx.doi.org/10.1007/s001220051266
Projects:	EU contract T5–3CT920150
Funders:	French Government
Acknowledgement:	[NOTE: D. A. Hoisington is presently with ICRISAT (Patancheru)]---This work involved a lot of teams throughout the world. We thank D. Beck, J. Betrán, and M. Willcox from the Maize Program at CIMMYT-Mexico, for their helpful assistance in producing the material. We also thank very much E. Pérez, G. Palacios and A. Bouet for their technical assistance in the laboratory. S. Mawere, T. Gumunyui, R.-P. Hoareau, M. Grondin are gratefully acknowledged for their help in the field work. We also thank C. Lanaud for the welcome in AGETROP lab, L. Grivet and M. Peterschmitt for helpful discussions. This work could not have been done without a graduate student fellowship provided by the French government. It was part of the EU contract T5– 3CT920150.
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