Biplot analysis of diallel crosses of early maturing tropical yellow maize inbreds in stress and nonstress environments

Published online: 23 Nov. 2010Appropriate testers are needed as well as information on heterotic patterns of tropical lowland early-maturing germplasm. Diallel crosses involving nine tropical early maturing maize (Zea mays L.) inbreds were evaluated at five locations in Nigeria from 2007 to 2009 under drought stress, when Striga infested, and in optimal growing conditions to examine the combining abilities and heterotic patterns and identify appropriate testers. Results revealed that TZEI 17 was the closest to the ideal tester and may be considered as the best under drought stress, TZEI 23 and TZEI 9 under artificial Striga infestation, and TZEI 13 across growing conditions. No appropriate tester was identified for the optimal growing conditions. Inbreds were placed in three contrasting tester groups under drought stress, and four groups each were placed under Striga infestation and optimal growing conditions and across research environments. Hybrids between inbreds in contrasting tester groups of each research environment are expected to show heterosis. TZEI 23 × TZEI 13 had a superior performance under all research conditions, suggesting that it has a broad adaptation. Classification of inbreds into distinct tester groups was not possible for 33% of the inbreds under drought stress and for 22% when Striga infested, under optimal growing conditions, and across the test environments

New models for homeland security and public safety

The standard approach to mathematical optimization is to construct models which assume 1) perfect knowledge of the algebraic form of the optimizable function, and 2) that the problem parameters are not subject to external random influences. In many practical settings, these assumptions are often too strong because even moderate amounts of randomness can lead to considerably sub-optimal outcomes. This dissertation examines three such problems within the general arena of public security, and proposes new mechanisms to cope with the underlying uncertainty involved in them. The first problem is a discrete optimization problem in which we seek (in the theater of battle) to properly configure a number of unmanned aerial vehicles subject to budget, weight, and size constraints. The objective is to select the best set of components so as to constitute a fleet which on average maximizes some payoff function whose closed algebraic form is unknown. To tackle this challenge, we introduce a new simulation-based heuristic that uses an adaptive criterion to sample the solution space, and efficiently distribute valuable simulation time among promising candidate solutions. The next problem is a patrol problem in which we need to allocate a budget resource both to the detection of illicit activity on some area of interest, and to the dispatching of patrol agents to disrupt or resolve those incidents. Moreover, these illegal activities are resolvable only before certain time deadlines that could be unknown. We show how to construct routes that guarantee minimum desired probabilities for resolving these incidents, and experimental results suggest that a larger budget can help neutralize the adverse impact of deadline uncertainty. The final problem entails an emergency response scenario in which aid workers tour relief centers while accumulating valuable relief supplies destined to serve deprived populations in the wake of a disaster. Situational urgency requires that these target populations be served before deadlines that are subject to random variation as new victims arrive. Moreover, potentially disruptive secondary disasters may also introduce randomness in the travel times on the paths between relief centers, and between relief centers and populations. We propose a new optimization framework to help these relief workers assess the value of routing options against the probabilities of these routes leading to missed deadlines (i.e., infeasibility risk). (Published By University of Alabama Libraries

Role of solanum dulcamara l. In potato late blight epidemiology

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