Combining ability of maize grain yield under different levels of environmental stress

Leandro Vagno De Souza,Lauro José Moreira Guimarães,João Carlos Cardoso Galvão,Glauco Vieira Miranda,Izabel Cristina Dos Santos

doi:10.1590/s0100-204x2009001000013

Abstract

The objectives of this work were to caracterize the tropical maize germplasm and to compare the combining abilities of maize grain yield under different levels of environmental stress. A diallel was performed among tropical maize cultivars with wide adaptability, whose hybrid combinations were evaluated in two sowing dates, in two years. The significance of the environmental effect emphasized the environmental contrasts. Based on grain yield, the environments were classified as favorable (8,331 kg ha-1), low stress (6,637 kg ha-1), high stress (5,495 kg ha-1), and intense stress (2,443 kg ha-1). None of the genetic effects were significant in favorable and intense stress environments, indicating that there was low germplasm variability under these conditions. In low and high stresses, the specific combining ability effects (SCA) were significant, showing that the nonadditive genetic effects were the most important, and that it is possible to select parent pairs with breeding potential. SCA and grain yield showed significant correlations only between the closer environment pairs like favorable/low stress and high/intense stress. The genetic control of grain yield differed under contrasting stress environments for which maize cultivars with wide adaptability are not adequate.

Highlights

Breeding maize adapted to stressed environment was described as the primary cause of increased grain yield over the last seventy years in Iowa, USA
The interaction between maize productivity and plant density in the USA was explained using canopy and root system architecture by simulation studies, but the last trait with water capture had a direct effect on biomass accumulation and historical yield trends (Hammer et al, 2009)
Studies done by Castleberry et al (1984) show that genetic gains are different across contrasting environments and that genetic gains are higher in environments that do not cause any type of stress

Summary

Introduction

Breeding maize adapted to stressed environment was described as the primary cause of increased grain yield over the last seventy years in Iowa, USA. The interaction between maize productivity and plant density in the USA was explained using canopy and root system architecture by simulation studies, but the last trait with water capture had a direct effect on biomass accumulation and historical yield trends (Hammer et al, 2009). The development of cultivars adapted to abiotic stress conditions is of utmost importance for food security. A successful plant breeding program is directly related to the superiority of the new cultivars. Cardwell (1982) showed that the annual maize yield increase in Minnesota was 85 kg ha‐1, with 43% of this increase due to the introduction of new cultivars. In order to improve plant breeding efficiency under stress conditions, parental selection must be based on results obtained in that specific environment

Objectives

Methods

Results