Construction and Efficiency of Selection Indices in Wheat (Triticum aestivum L.) under Drought Stress and Well-Irrigated Conditions

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/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Aggregate selection helps making selection decisions for improved profitability and permits to exploit information on correlated traits to improve accuracy. In the present study, the efficiency of trait selection was assessed by the Smith-Hazel (SHI) and the Pesek-Baker (PBI) models in 35 wheat genotypes under drought stress at heading and well-irrigated conditions at the Research Farm of Shiraz University, Iran in 2011 and 2012 years. The analysis of correlated response (CR) revealed that thousand grain weight (TGW) with CR = 24.05 (in 2011) and 9.15 (in 2012) and harvest index (HI) with CR = 18.37 (in 2011) and 9.08 (in 2012) had higher indirect effects on grain yield (GY) increase under drought stress. In both years, biological yield (BY), grain number/spike (GN), TGW, and GY had the highest genetic gain (ΔG) in SHI model. The top ten landraces in PBI for the trials in 2011 were also placed in the top rankings for grain yield under drought stress conditions. These results and estimation of the efficiency of selection (ΔH) revealed that PBI (ΔH = 19.95 and 16.5 in the first and 11.15 and 11.06 in the second year) was more efficient than SHI (ΔH = 9.58 and 8.97 in the first and 9.74 and 8.59 in the second year) in view of identifying superior genotypes based on aggregate trait selection. Overall, repeatability estimates for grain yield (33%-57.8%) was relatively low showing that individual plant selection has low efficiency for wheat improvement whilst aggregate trait selections leads to relatively high genetic gain (1.63-2.75) for grain yield.

Breeding for silicon-use efficiency, protein content and drought tolerance in bread wheat ( Triticum aestivum L.): a review

“…Successful breeding for drought tolerance will depend on the availability of adequate genetic variation for selection. Genetic variation for agronomic traits that could be useful for improving tolerance to drought has been reported previously (Ghaed-Rahimi et al 2017). World wheat genetic resources are available for improving drought tolerance in locally adapted varieties, including modern and obsolete cultivars, landraces, breeding populations and wild relatives, and are maintained and catalogued by several international and national research programmes and genebanks (Mwadzingeni et al, 2017).…”

“…The effect of Si is most widely studied under stressed conditions (Zargar et al 2019). Genetic variation for Si-utilisation under drought stress conditions has not been widely exploited for improving drought tolerance, despite knowledge of its important role in plant nutrient uptake and remobilisation, and protection against biotic and abiotic stresses (Gokulraj et al 2018;Prasanna et al 2018). McLarnon et al (2017) reported significant genotypic variation for Si uptake in grasses.…”

Evaluation of Relative Efficiency of Several Selection Indices for Prediction of Expected Genetic Advance in Bread Wheat Grain Yield (Triticum aestivum L)

“…Robinson et al (1951) provided methods for estimating genetic and phenotypic variances and covariance's required to establish selection indices. Numerous studies have been carried out by researchers in this field, dealing with the selection indices in wheat and some other self-fertilized crops, among them were, Wells and Kofoid (1986), Ahmad and Hamdo (2000), Al-Jubouri et al (2006), Taha (2007), Laghari et al (2010), Ahmed et al (2011), Dawod et al (2012), Raiyani et al (2015), Sahar et al (2016) and Ghaed-Rahimi et al (2017), whose results indicated that some election indices, consisting of several traits, outweighed the direct selection of the yield alone, some were characterized by a high relative efficiency and expected genetic improvement as a result of selection.…”