A proposed selection criterion for drought resistance across multiple environments in maize

Abstract

Drought resistance is a complex quantitative trait, involving interactions of many metabolic pathways related to stress-resistant genes. Identification of a standard evaluation assay has been the most pressing problem for selection of drought-resistant genotypes and ultimately for elucidating the internal genetic mechanisms. A field phenotypic investigation was performed on more than 20 morphological traits and grain yield and its components for 201 Chinese common inbred maize (Zea mays L.) lines under water deficit in seven environments. An integrated selection criterion for drought resistance was proposed and used to identify droughtresistant maize genotypes. In it, six traits including grain yield, ear number per plant, kernel number per ear, plant height, anthesis-silking interval and degree of leaf curling were chosen as the most relevant factors related to drought resistance, as determined by statistical analysis. The integrated selection criterion was highly correlated with grain yield under both well-watered and water-stressed regimes, and was also highly correlated with other commonly used selection criteria. Moreover, for 128 (63.7%) inbred lines the evaluation result with this criterion was consistent across more than three environments thus avoiding the effect of genotype-environment interaction, though stress level between the different environments largely fluctuated. There were 43 inbred lines evaluated for drought-resistance and most were bred during 1990-2000. The criterion will be useful to identify excellent drought-resistant genotypes in future maize molecular breeding programs.

Effect of drought stress on mungbean (Vigna radiataL.) under arid climatic conditions of Saudi Arabia

“…Here again the gradual increase in water deficit conditions regularly reduced the seed yield for all three genotypes. These findings corroborated the results reported by Hao et al [23] who stated that irrigation stress may reduce the mungbean seed yield and affect WUE. WUE: the major object of this research and the aggregate of all physiological, genetic and phonological mechanisms of plants under certain situations was recorded as highest for VC-2010 and I4 combination followed by Kawmay-1.…”

“…Crop plants are usually under stress at one time or another and plant species able to withstand such stresses have great economic potential [22]. Use of drought tolerant species is one of the effective strategies used to cope with water deficit stress wisely, as some plants species are able to withstand such stresses [21][22][23]. The proper application of deficit irrigation practices can generate significant saving in irrigation water supplies [21,24].…”

Assessment of drought tolerance in barley: integrated selection criterion and drought tolerance indices

“…Five drought resistance indices including stress tolerance index (STI), mean production (MP), geometric mean production (GMP), stress susceptibility (SSI), and yield stability index (YSI), were calculated using the following relationships (Fischer, Maurer 1978;Rosielle, Hamblin 1981;Fernandez 1992;Gavuzzi et al 1997): where Y p is particular yield in non-stress conditions, Y s is particular yield in stress conditions, Y p is mean yield in non-stress conditions, Y s is mean yield in stress conditions. The integrated selection index (SI) was calculated according to Hao et al (2011) on the basis of the obtained results from factor analysis for agro-morphological traits under non-stress and water deficit stress conditions using the following steps:…”

“…These agronomic traits are simple criteria for drought tolerance, and using these traits in integrated selection criterion (SI) decreases the risk of selection of tolerant lines. Likewise, Hao et al (2011) and used the integrated selection index (SI) to screen tolerance genotypes of corn and barley under normal and stress conditions, respectively. Principal components analysis showed that PCA1 and PCA2 explained 98.2% of the total yield variation, hence the first and second component were named as yield potential and stress susceptibility, respectively.…”

“…Recently, Hao et al (2011) introduced a new selection criterion to assess response of genotypes to drought stress across multiple environments. They declared that this new index, integrated selection criterion (SI), provides an estimate of drought stress resistance based on grain yield and related agronomic characters, and thus it would be useful in identifying excellent drought-resistant genotypes in breeding programmes.…”