Nicotiana langsdorffii is one of two species of Nicotiana known to express an incompatible interaction with the oomycete Peronospora tabacina, the causal agent of tobacco blue mold disease. We previously showed that incompatibility is due to the hypersensitive response (HR), and plants expressing the HR are resistant to P. tabacina at all stages of growth. Resistance is due to a single dominant...

The Ranunculus auricomus complex is an interesting model system for studying the evolution and diversity of apomictic polyploid complexes. It comprises hundreds of agamospecies, usually referred to two distinct morphotypes (traditionally named "R. auricomus" and "R. cassubicus") which are connected by several intermediate forms. Here we try to elucidate the evolution of apomictic "cassubicus" m...

ABSTRACT A marked-isolate, release-recapture experiment was conducted to assess the relative contributions of seed-transmitted (released isolates) versus all other inocula to foliar and grain populations of Phaeosphaeria nodorum in winter wheat rotated with nonsusceptible crops in New York and Georgia, United States. Seed infected with two distinct groups of marked isolates of P. nodorum contai...

Landscape genetics has seen rapid growth in number of publications since the term was coined in 2003. An extensive literature search from 1998 to 2008 using keywords associated with landscape genetics yielded 655 articles encompassing a vast array of study organisms, study designs and methodology. These publications were screened to identify 174 studies that explicitly incorporated at least one...

Changes in growth forms frequently accompany plant adaptive radiations, including páramo-a high-elevation treeless habitat type of the northern Andes. We tested whether diverse group of Senecio inhabiting montane forests and páramo represented such growth form changes. We also investigated the role of Andean geography and environment in structuring genetic variation of this group. We sampled 10...

Examining species boundaries using data from multiple independent sources is an appropriate and robust method to identify genetically isolated evolutionary units. We used 5 data sets—cytochrome b (Cytb), cytochrome c oxidase (COI), amplified fragment length polymorphisms (AFLPs), karyotypes, and morphology—to estimate phylogenetic relationships and species limits within woolly bats, genus Keriv...

M. TARIQ EZAZ INSTITUTE OF AQUACULTURE PHD THESIS ii ABSTRACT Seven families of XX and YY homozygous Oreochromis niloticus were produced by mitotic gynogenesis from XY neofemales and their genetic status was verified by multilocus DNA fingerprinting and progeny testing. Two of these gynogenetic families and their corresponding diploid controls were used with 64 AFLP primer combinations in diffe...