Preplant soil fumigation has been the standard treatment for the control of perennial crop replant diseases, including apple replant disease (8,10). Although significant effort has been invested in the development of alternatives to soil fumigation for control of replant diseases (5,21– 23,26–28,30,31), there continues to be a lack of effective and economically feasible nonfumigant control stra...

We present two minimum residual methods for solving sequences of shifted linear systems, the right-preconditioned shifted GMRES and shifted Recycled GMRES algorithms which use a seed projection strategy often employed to solve multiple related problems. These methods are compatible with general preconditioning of all systems, and when restricted to right preconditioning, require no extra applic...

Seed is the basic input in agriculture. The quality of seed used by farmers determines the status of agriculture they practice. However, for maximum gain in productivity the use of both improved varieties and improved integrated crop management practices are required. Not only do they contribute to increasing productivity individually, but they also act synergistically. Seed of improved varieti...

Although terrestrial CO2 concentrations, [CO2] are not expected to reach 1000 micromoles mol-1 for many decades, CO2 levels in closed systems such as growth chambers and glasshouses, can easily exceed this concentration. CO2 levels in life support systems in space can exceed 10000 micromoles mol-1 (1%). Here we studied the effect of six CO2 concentrations, from ambient up to 10000 micromoles mo...

Previous studies demonstrated the effects of polyploidy on various aspects of plant life. It is, however, difficult to determine which plant characteristics are responsible for fitness differences between cytotypes. We assessed the relationship between polyploidy and seed production. To separate the effects of flowering phenology, flower head size and herbivores from other possible causes, we c...