Phenotype Uniformity in Combined-Stress Environments has a Different Genetic Architecture than in Single-Stress Treatments

Ann E Stapleton,G Buddhika Makumburage

doi:10.3389/fpls.2011.00012

Abstract

For crop production it is desirable for the mapping between genotype and phenotype to be consistent, such that an optimized genotype produces uniform sets of individual plants. Uniformity is strongly selected in breeding programs, usually automatically, as harvest equipment eliminates severely non-uniform individuals. Uniformity is genetically controlled, is known to be increased by interplant competition, and is predicted to increase upon abiotic stress. We mapped maize loci controlling genotype by environment interaction in plant height uniformity. These loci are different than the loci controlling mean plant height. Uniformity decreases upon combining two abiotic stresses, with alleles conferring greater uniformity in a single stress showing little improvement in a combined stress treatment. The maize B73 and Mo17 inbreds do not provide segregating alleles for improvement in plant height uniformity, suggesting that the genetic network specifying plant height has a past history of selection for robustness.

Highlights

The ability of one genotype to specify a phenotype consistently – the phenotype uniformity – is a key target for selective breeding in crops (Fasoula and Tollenaar, 2005)
Plant height phenotype stability is important for yield in certain environments, such as no-till in maize (Boomsma et al, 2010)
We show that height uniformity is genetically controlled, and that non-linear genotype by environment interactions results in some loci controlling uniformity only in combined-stress environments (Figure 3)

Summary

Introduction

The ability of one genotype to specify a phenotype consistently – the phenotype uniformity – is a key target for selective breeding in crops (Fasoula and Tollenaar, 2005). To emphasize the resistance of biological systems to change in the extent of phenotype specification, terms such robustness, buffering, and canalization are used, with specific proteins or network structures that confer this feature referred to as capacitors (Masel and Siegal, 2009). Both genetic variation – epistasis and new mutations – and environmental variation contribute to varying phenotypes within one genotype (Zhang, 2008; Fraser and Schadt, 2010). Genetic control of macro-environmental factor phenotype stability has been mapped in Arabidopsis as well (Hall et al, 2007)

Methods

Results

Conclusion