Breeding for Drought and Nitrogen
Stress Tolerance in Maize

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Abstract.-  Targeted initially for maize breeders in sub-Saharan Africa, this manual is based on a successful approach developed at CIMMYT for improving the tolerance of maize to drought and low nitrogen stress. Intended as a supplement to a course for breeders and agronomists of at least BSc level, the manual deals with the effects of water and N deficits on the maize plant, the level of yield increases to be expected from selection, factors that affect the severity of drought and low N stress in maize, selecting suitable fields for drought and low N screening, managing uniform stress in drought or low N experiments, designing effective experiments and field layouts for stress trials, the choice and analysis of data, and the use of drought and low N screening in a normal breeding program.

Contents PDF (20.47KB)

1. Introduction - Why breed for drought and low N tolerance?  PDF (90.96KB)

  • 1.1 Conceptual framework - Breeding

  • 1.2 Conventional approaches to improving the drought and low N tolerance of maize

  • 1.3 Conventional approaches challenged

  • 1.4 The challenge of breeding for drought and low N tolerance

2. Maize under drought and low N stress

  • 2.1 Conceptual framework - Physiology

  • 2.2 Water and the maize plant

  • 2.3 Nitrogen and the maize plant

  • 2.4 Maize under drought and low N stress - Consequences for breeding

3. Stress management 

  • 3.1 Drought 

  • 3.2 Low N stress

4. Statistical designs and layout of experiments PDF  (1093.85KB)

  • 4.1 Increasing the number of replicates

  • 4.2 Improved statistical designs

  • 4.3 Field layout

  • 4.4 Border effects from alleys 

5. Secondary traits

  • 5.1 Why use secondary traits?

  • 5.2 How do we decide on the value of secondary traits in a drought or low N breeding program?

  • 5.3 Secondary traits that help to identify drought tolerance

  • 5.4 Secondary traits that help to identify low N tolerance

  • 5.5 Selection indices - Combining information on secondary traits with grain yield

  • 5.6 Combining information from various experiments

6. Breeding strategies PDF (84.24KB)

  • 6.1 Introduction

  • 6.2 Choice of germplasm

  • 6.3 Breeding schemes

  • 6.4 Biotechnology: potential and constraints for improving drought and low N tolerance

7. The role of the farmer in selection

  • 7.1 What is farmer participatory research and why is important?

  • 7.2 What is new about farmer participatory research?

  • 7.3 Participatory methodologies

  • 7.4 Conclusions

8 Literature PDF (19.80KB)

Published on 2000

August, 2004