<> "The repository administrator has not yet configured an RDF license."^^ . <> . . . "Field screening for drought tolerance - principles and illustrations"^^ . "Establishing a screening procedure for genetic differences in drought tolerance\r\ninvolves 1) practical decisions on the objectives of such a screening program,\r\n2) the selection of environment(s) and stress occurrence(s) to be targeted in\r\nthe program, and 3) the design and operation of field physical facilities and\r\nexperimental methods to apply a uniform, repeatable drought stress. This\r\npaper considers these points from a conceptual and a practical viewpoint.\r\nDrought tolerance can be approached on various plant organizational\r\nlevels, from crop yield stability under stress, through responses to stress\r\nindicative of tolerance, to the biological mechanisms that underlie these\r\nresponses, to the genes and alleles governing the presence or expression of the\r\nresponses/mechanisms. Defining stress tolerance at each level has specific\r\nadvantages and disadvantages for designing a field-screening program. Work on\r\npearl millet has mainly focused on the crop tolerance response level, targeting\r\nthe relative ability of genotypes to maintain grain numbers per panicle and\r\nseed filling in terminal stress environments.\r\nTarget environments and target stress occurrences for a screening\r\nprogram must be established from the analysis of historical climate data.\r\nWater budgeting is probably the minimum level, but opportunities to use crop\r\nsimulation modeling for this purpose are improving. Establishing screening\r\nsystems with environmental conditions representative of the target\r\nenvironment, is difficult, involving a major tradeoff between providing\r\nrepresentative daylength, vapor pressure, and temperature conditions, and\r\neasily managing soil water/rainfall. In contrast, duplicating target environment\r\nmoisture patterns in non-target environments is easier, but G x E effects can\r\nbe a problem.\r\nThe effectiveness of a drought screening procedure is best measured by\r\nthe genetic heritabilities achieved for target traits, whether the focus is nurseries therefore requires careful analysis of likely sources of nongenetic\r\nvariation among plots, replications, and repeated experiments, and seeing that\r\nthese are minimized. These include 1) the choice of site for screening, 2) the\r\nphysical management of both water-related and non water-related sources of\r\nvariation in crop growth within and across experiments, 3) the choice of\r\nexperimental design and the effective use of blocking to remove expected\r\nsources of nonmanageable variation, and 4) the efficient collection and\r\nmanagement of data. These considerations are illustrated here with examples\r\nfrom the pearl millet drought screening system used at ICRISAT."^^ . "2002" . . . "International Crops Research Institute for the Semi-Arid Tropics "^^ . . . . . . . . "F R"^^ . "Bidinger"^^ . "F R Bidinger"^^ . . . . . . "Field screening for drought tolerance - principles and illustrations (PDF)"^^ . . . . . "Field screening for drought tolerance - principles and illustrations (Other)"^^ . . . . . . "Field screening for drought tolerance - principles and illustrations (Other)"^^ . . . . . . "Field screening for drought tolerance - principles and illustrations (Other)"^^ . . . . . . "Field screening for drought tolerance - principles and illustrations (Other)"^^ . . . . . . "Field screening for drought tolerance - principles and illustrations (Other)"^^ . . . . . "HTML Summary of #6679 \n\nField screening for drought tolerance - principles and illustrations\n\n" . "text/html" . . . "Agriculture-Farming, Production, Technology, Economics"@en . .