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Field screening for drought tolerance - principles and illustrations

OAR@ICRISAT

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Relation http://oar.icrisat.org/6679/
 
Title Field screening for drought tolerance - principles and illustrations
 
Creator Bidinger, F R
 
Subject Agriculture-Farming, Production, Technology, Economics
 
Description Establishing a screening procedure for genetic differences in drought tolerance
involves 1) practical decisions on the objectives of such a screening program,
2) the selection of environment(s) and stress occurrence(s) to be targeted in
the program, and 3) the design and operation of field physical facilities and
experimental methods to apply a uniform, repeatable drought stress. This
paper considers these points from a conceptual and a practical viewpoint.
Drought tolerance can be approached on various plant organizational
levels, from crop yield stability under stress, through responses to stress
indicative of tolerance, to the biological mechanisms that underlie these
responses, to the genes and alleles governing the presence or expression of the
responses/mechanisms. Defining stress tolerance at each level has specific
advantages and disadvantages for designing a field-screening program. Work on
pearl millet has mainly focused on the crop tolerance response level, targeting
the relative ability of genotypes to maintain grain numbers per panicle and
seed filling in terminal stress environments.
Target environments and target stress occurrences for a screening
program must be established from the analysis of historical climate data.
Water budgeting is probably the minimum level, but opportunities to use crop
simulation modeling for this purpose are improving. Establishing screening
systems with environmental conditions representative of the target
environment, is difficult, involving a major tradeoff between providing
representative daylength, vapor pressure, and temperature conditions, and
easily managing soil water/rainfall. In contrast, duplicating target environment
moisture patterns in non-target environments is easier, but G x E effects can
be a problem.
The effectiveness of a drought screening procedure is best measured by
the genetic heritabilities achieved for target traits, whether the focus is nurseries therefore requires careful analysis of likely sources of nongenetic
variation among plots, replications, and repeated experiments, and seeing that
these are minimized. These include 1) the choice of site for screening, 2) the
physical management of both water-related and non water-related sources of
variation in crop growth within and across experiments, 3) the choice of
experimental design and the effective use of blocking to remove expected
sources of nonmanageable variation, and 4) the efficient collection and
management of data. These considerations are illustrated here with examples
from the pearl millet drought screening system used at ICRISAT.
 
Publisher International Crops Research Institute for the Semi-Arid Tropics
 
Date 2002
 
Type Book Section
PeerReviewed
 
Format application/pdf
 
Language en
 
Rights —
 
Identifier http://oar.icrisat.org/6679/1/FieldScreening_BookChap_2002.pdf
Bidinger, F R (2002) Field screening for drought tolerance - principles and illustrations. In: Field Screening for Drought Tolerance in Crop Plants with Emphasis on Rice. International Crops Research Institute for the Semi-Arid Tropics , Patancheru, Andhra Pradesh, India, pp. 109-124.