Publications des agents du Cirad


A complete resistance to maize streak virus originating in Mascarene germplasm, inherance and gene mapping

Dintinger J., Pernet A., Reynaud B., Marchand J.L.. 1997. In : 1st International Maize Streak Disease Symposium, Hazyview, South Africa, September 9th - 11th 1997. s.l. : s.n., 1 p.. Maize Streak Disease Symposium. 1, 1997-09-09/1997-09-11, Hazyview (Afrique du Sud).

Maize streak virus (MSV) appears as an increasing major threat for maize production in Africa especially in the areas where the disease is endemie and can cause heavy grainyie1d losses. Very few resistance sources have been found in the world. Completely resistant lines can be selected from la Reunion germplasm and used as a donor in backcrossing schemes. In order to understand the genetic control of this resistance a cross between the D2 II completely resistant line and the B73 susceptible line has been used to produce generations segregating for MSV-resistance. The study of the genetic determinism was carried out by generation mean analysis method from these generations. The F2 population was mapped using RFLP markers, and Q'IL for MSV-resistance were identified. The analysis of the-genetic determinism revealed that this complete resistance is quantitatively inherited. It is oligogenic and has a partial positive dominance. The quite high value of the additive component of genetic variation and the high values of heritability indicate that a simple mass selectionscheme can be very efficient to improve this characteristic. The estimation of two or three genetic factors according to the results of Mather & Jinks formula is confinned by the RFLP detection of three Q'IL, one major on chromosome 1 explaining 53 % of the phenotypic variance, and two others on chromosome 10 with minor effects. The durability of this resistance cannot be easily predicted because it depends both on the variability of the pathogen, and on the efficiency of the genes controlling this resistance. However, the oligogenic system from la Reunion should be more durable than the other sources of resistance which were found elsewhere to be rather monogenic. (Texte intégral)
Communication de congrès

Agents Cirad, auteurs de cette publication :