Graphical analysis of multi-environmental trials for wheat grain yield based on GGE-biplot analysis under diverse sowing dates

Abstract Background Information on the nature and extent of genetic and genotype × environment (GE) interaction is extremely rare in wheat varieties under different sowing dates. In the present study, the GGE biplot method was conducted to investigate genotype × environment interaction effects and evaluate the adaptability and yield stability of 13 wheat varieties across eight sowing dates, in order to facilitate comparison among varieties and sowing dates and identify suitable varieties for the future breeding studies. Results Considerable genotypic variation was observed among genotypes for all of the evaluated traits, demonstrating that selection for these traits would be successful. Low broad sense heritability obtained for grain yield showed that, both genetic and non-genetic gene actions played a role in the control of this trait, and suggested that indirect selection based on its components which had high heritability and high correlation with yield, would be more effective to improve grain yield in this germplasm. Hence, selection based on an index may be more useful for improvement of this trait in recurrent selection programs. The results of the stability analysis showed that the environmental effect was a major source of variation, which captured 72.21% of total variation, whereas G and GE explained 6.94% and 18.33%, respectively. The partitioning of GGE through GGE biplot analysis showed that, the first two PCs accounted for 54.64% and 35.15% of the GGE sum of squares respectively, capturing a total of 89.79% variation. According to the GGE biplot, among the studied varieties, the performance of Gascogen was the least stable, whereas Sirvan, Roshan, and Pishtaz had superior performance under all sowing dates, suggesting that they have a broad adaptation to the diverse sowing dates. These varieties may be recommended for genetic improvement of wheat with a high degree of adaptation. Conclusion The results obtained in this study demonstrated the efficiency of the GGE biplot technique for selecting high yielding and stable varieties across sowing dates

Association analysis revealed loci linked to post-drought recovery and traits related to persistence of smooth bromegrass (Bromus inermis)

Association analysis has been proven as a powerful tool for the genetic dissection of complex traits. This study was conducted to identify association of recovery, persistence, and summer dormancy with sequence related amplified polymorphism (SRAP) markers in 36 smooth bromegrass genotypes under two moisture conditions and find stable associations. In this study, a diverse panel of polycross-derived progenies of smooth bromegrass was phenotyped under normal and water deficit regimes for three consecutive years. Under water deficit, dry matter yield of cut 1 was approximately reduced by 36, 39, and 37% during 2013, 2014, and 2015, respectively, compared with the normal regime. For dry matter yield of cut 2, these reductions were approximately 38, 60, and 56% in the same three consecutive years relative to normal regime. Moreover, water deficit decreased the RY and PER of the genotypes by 35 and 28%, respectively. Thirty primer combinations were screened by polymerase chain reaction (PCR). From these, 541 polymorphic bands were developed and subjected to association analysis using the mixed linear model (MLM). Population structure analysis identified five main subpopulations possessing significant genetic differences. Association analysis identified 69 and 46 marker-trait associations under normal and water deficit regimes, respectively. Some of these markers were associated with more than one trait; which can be attributed to pleiotropic effects or tightly linked genes affecting several traits. In normal and water-deficit regimes, these markers could potentially be incorporated into marker-assisted selection and targeted trait introgression for the improvement of drought tolerance of smooth bromegrass

The effect of water deficit, range, and genotypic coefficient of variation (GCV) of different traits recorded under normal and water deficit conditions in fennel genotypes during two years (2019–2020).

The effect of water deficit, range, and genotypic coefficient of variation (GCV) of different traits recorded under normal and water deficit conditions in fennel genotypes during two years (2019–2020).</p

General combining ability (GCA) of some important agro-morphological characters and essential oil content of OP population of fennel during 2019–2020 under normal and water deficit conditions.

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Fig 3 -

Biplot of seed yield per plant (SYP) vs. inbreeding depression (ID) for S1 population of fennel under (a) normal condition and (b) water deficit condition. There was significant association between SYP and ID under normal (r = 0.68 **) and water deficit (r = 0.77 **) conditions. The F-test indicated that the model is significant for normal and water deficit conditions in 0.01 probability level.</p

Fig 1 -

Seed yield per plant (SYP) of 29 selfed (S1) and open-pollinated (OP) populations of fennel under normal (a) and water deficit (b) conditions. The F-test indicated that the model is significant for normal condition in 0.01 probability level, and for water deficit condition is not significant.</p

Fig 2 -

Essential oil content (EOC) of 29 selfed (S1) and open-pollinated (OP) populations of fennel under normal (a) and water deficit (b) conditions. The F-test indicated that the model is not significant for normal condition, and for water deficit condition is significant in 0.05 probability level.</p

The percentage of inbreeding depression in some important traits of selfed fennel genotypes (S1) under normal and water deficit conditions during two years (2019–2020).

The percentage of inbreeding depression in some important traits of selfed fennel genotypes (S1) under normal and water deficit conditions during two years (2019–2020).</p

Mean comparisons of some important agro-morphological characters and essential oil content of OP population of fennel during 2019–2020 under normal and water deficit conditions.

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Effect of selfing on different traits of fennel under normal and water deficit conditions during two years (2019–2020).

Effect of selfing on different traits of fennel under normal and water deficit conditions during two years (2019–2020).</p