Indian Society of Genetics & Plant Breeding

Understanding the genetic architecture of resistance to northern corn leaf blight and southern corn rust in maize (Zea mays L.)

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Among various foliar diseases, northern corn leaf blight
(NCLB) incited by Exserohilum turcicum (Pass) Leonard
and Suggs and southern corn rust (SCR) caused by
Puccinia polysora (Underwood) are the most persistent
and destructive biotic constraints in India and worldwide.
The present investigation was conducted to understand
the genetics of resistance to both diseases through six
generation means and variances in two crosses developed
by crossing two elite NCLB and SCR susceptible inbreds
(CM212 and HKI162) with a common resistant inbred SKV50.
Six generations of the two crosses (CM212 × SKV50 and
HKI162 × SKV50) were evaluated in the disease screening
nurseries for NCLB and SCR resistance at hot spot location
during post rainy season of 2012 and 2013. The scaling
tests and joint scaling tests indicated the inadequacy of
additive-dominance model and showed the presence of
epistatic gene effects in both the crosses for NCLB and
SCR resistance. Study further revealed the importance of
additive, dominance and additive × additive gene effects in
the expression of NCLB and SCR. Duplicate gene interaction
was evident in the inheritance of NCLB and SCR resistance
in both the crosses. The study also revealed that genetic
architecture of NCLB and SCR resistance was population
specific. Both, additive and non-additive components were
found important thus reciprocal recurrent selection would
be more effective in developing NCLB and SCR resistant
maize genotypes.

Keywords: Generation means, additive-dominance model, duplicate gene interaction, recurrent selection


Year: 2017
Volume: 77
Issue: 3
Article DOI: 10.5958/0975-6906.2017.00048.7
Print ISSN: 0019-5200
Online ISSN: 0975-6906


H. C. Lohithaswa info_circle
Anand S. Pandravada info_circle

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