A Diallel Analysis of Drought Tolerance Indices at Seedling Stage in Bread Wheat (Triticum aestivum L.)

Abstract

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.Plant Breed. Biotech. 2014 (September) 2(3):276~288 http://dx.ABSTRACT Drought is one of the most important abiotic factors affecting wheat production and development of tolerant genotypes is limited by the lack of effective selection criteria. A genetic analysis of drought tolerance indices at seedling stage (i.e. root length, shoot length, root/shoot ratio and seedling dry weight) was performed for a seven-parent half diallel cross of bread wheat (Triticum aestivum L.) in Egypt. The parents and their F2 progenies were evaluated in the laboratory under osmotic stress induced by polyethylene glycol (PEG) with five treatments (i.e. 0, 5, 10, 15 and 20% PEG-6000). Grain yield per spike was also evaluated under drought stressed field conditions. The parent P7 had maximum root and shoot lengths under stress conditions, highest root/shoot ratio under 20% PEG and higher grain yield per spike than the other parents suggesting that P7 possessed stress tolerance genes. Grain yield/spike was significantly correlated with root length (r= 0.41, P<0.05) and seedling dry weight (r= 0.46, P<0.05) at 15% PEG. Both additive and non-additive gene effects were involved in the genetic control of all traits. Rather low to moderately narrow-sense heritability was obtained for root length (0.18 and 0.12) and shoot length (0.19 and 0.12) at 15 and 20% PEG, respectively; root/shoot ratio (0.15) and seedling dry weight (0.16) at 15% PEG. Moderate genetic advance was observed for root length (41.24%) and shoot length (29.96%) under stress conditions suggesting that selection could be practiced on both traits for improving drought tolerance in wheat breeding programs.

QTL mapping for seedling morphology under drought stress in wheat cross synthetic (W7984)/Opata

“…Grain yield is a complex trait with strong genotype by environment interactions. Grain yield is significantly correlated with seedling traits such as root length (RL), shoot length (SL) and dry root weight (DRW) (El-Rawy and Hassan, 2014). Therefore, adaptive traits less influenced by environment like physiological and seedling emergence traits are targeted to understand the genetics of drought adaptability (Acuna- Galindo et al , 2015).…”

Generation Mean Analysis and Molecular Markers for Drought Tolerance in Wheat during Germination and Seedling Stage

“…Wheat often experiences drought stress at various growth stages especially during germination, tillering and early grain filling with corresponding depressions in biomass production and grain yield under drought conditions. Several researchers had studied the effects of drought on germination and seedling development in wheat (Dhanda et al, 2004;Rauf et al, 2007;Bayoumi et al, 2008;Datta et al, 2011;Khakwani et al, 2011;Baloch et al, 2012;Ahmad et al, 2013;El-Rawy and Hassan, 2014). Polyethylene glycol (PEG) causes osmotic stress and could be used as a drought simulator (Turhan, 1997;Ashraf et al, 2006).…”

Identification and Validation of a Chromosome 4D Quantitative Trait Locus Hotspot Conferring Heat Tolerance in Common Wheat (Triticum aestivum L.)

“…Genotype evaluation at different stages is necessary to better understand the HT mechanism and to breed tolerant cultivars. Grain yield is significantly correlated with seedling traits such as root length and shoot length [ 8 ]. If the plant does not survive at a seedling stage, there will be no harvest.…”