Inheritance, Genetic Variability and Marker Detection for Rust Resistance in Groundnut (Arachis hypogaea L.)
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Date
2012
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UAS Dharwad
Abstract
A study was conducted to understand the inheritance of resistance to rust disease in
groundnut during 2009-2012. GPBD-5, a bold seeded, high yielding variety but susceptible to
rust disease was crossed to GPBD-4 and ICGV 86699 that are resistant to rust disease. The
F1, F2 and F3 populations of four crosses were evaluated along with parents for resistance to
rust disease under artificial epiphytotic condition. The study indicated that rust resistance in
host plant is controlled by single recessive gene. The direct (F2) and backcross (BC1F2, BC2F2
and BC3F2) populations developed in both crosses were evaluated for transgressive
segregation and subsequently derived F6, BC1F4, BC2F3 and BC3F2 populations were
evaluated for productivity and its component traits, along with resistance. There was high
genetic variability for the traits studied and resulted in identification of recombinants that
were high yielding and resistant to rust disease. Further, attempts were made to identify SSR
markers linked to rust resistance. Out of 135 SSR markers screened for parental
polymorphism, 36 were polymorphic and two of them TC5A06 and TC4g10 are cosegregated
with rust resistance.
Study of components of rust resistance in selected rust resistant lines derived from
direct and backcross populations revealed significant genotypic variation for component traits
and mean rust score viz., incubation period, number of postules, sporulation index, leaf area
damage and ruptured postules. All the components evaluated were significantly and
positively correlated except incubation period that had negative and significant correlation
with other resistance components. Similarly mean rust scores were negatively correlated with
incubation period and positively correlated with other resistance component. Study indicated
that incubation period, sporulation index and leaf area damage were important components of
rust resistance that can help in to identification of resistant lines.