Genetic dissection of the developmental behaviours of plant height in wheat under diverse water regimes

Plant height (PH), a crucial trait related to yield potential in crop plants, is known to be typically quantitatively inherited. However, its full expression can be inhibited by a limited water supply. In this study, the genetic basis of the developmental behaviour of PH was assessed in a 150-line wheat (Triticum aestivum L.) doubled haploid population (Hanxuan 10×Lumai 14) grown in 10 environments (year×site×water regime combinations) by unconditional and conditional quantitative trait locus (QTL) analyses in a mixed linear model. Genes that were expressed selectively during ontogeny were identified. No single QTL was continually active in all periods of PH growth, and QTLs with additive effects (A-QTLs) expressed in the period S1|S0 (the period from the original point to the jointing stage) formed a foundation for PH development. Additive main effects (a effects), which were mostly expressed in S1|S0, were more important than epistatic main effects (aa effects) or QTL×environment interaction (QE) effects, suggesting that S1|S0 was the most significant development period affecting PH growth. A few QTLs, such as QPh.cgb-6B.7, showed high adaptability for water-limited environments. Many QTLs, including four A-QTLs (QPh.cgb-2D.1, QPh.cgb-4B.1, QPh.cgb-4D.1, and QPh.cgb-5A.7) coincident with previously identified reduced height (Rht) genes (Rht8, Rht1, Rht2, and Rht9), interacted with more than one other QTL, indicating that the genetic architecture underlying PH development is a network of genes with additive and epistatic effects. Therefore, based on multilocus combinations in S1|S0, superior genotypes were predicted for guiding improvements in breeding for PH

Genetic Insight into Yield-Associated Traits of Wheat Grown in Multiple Rain-Fed Environments

Background: Grain yield is a key economic driver of successful wheat production. Due to its complex nature, little is known regarding its genetic control. The goal of this study was to identify important quantitative trait loci (QTL) directly and indirectly affecting grain yield using doubled haploid lines derived from a cross between Hanxuan 10 and Lumai 14. Methodology/Principal Findings: Ten yield-associated traits, including yield per plant (YP), number of spikes per plan

Favorable allele frequencies of the additive main QTLs for yield and yield-related traits in four 1000 grain weight (gw) - grain number per spike (gn) groups of wheat DH lines.

1<p>YP (g): Yield per plant; NSP: Number of spikes per plant; NGS: Number of grains per spike; TGW (g): 1000-grain weight; TNSS: Total number of spikelets per spike; NSSS: Number of sterile spikelets per spike; PFSS: Proportion of fertile spikelets per spike; SL (cm): Spike length; DSS: Density of spikelets per spike; PH (cm): Plant height;</p>2<p>The nearest marker of the associated QTL;</p>3<p>The parent contributing the favourite allele of QTL;</p>4<p>QTL favourite allele frequence in a group, viz, for a special marker, the number of favourite allele divided by the total line number. Approximately the value 0.70 is considered that the favourite allele is rich in the group, which is expressed in bold print.</p

Performances for traits of four 1000 grain weight (gw) - grain number per spike (gn) groups of wheat DH lines from analyses across different environments.

1<p>YP (g): Yield per plant; NSP: Number of spikes per plant; NGS: Number of grains per spike; TGW (g): 1000-grain weight; TNSS: Total number of spikelets per spike; NSSS: Number of sterile spikelets per spike; PFSS: Proportion of fertile spikelets per spike; SL (cm): Spike length; DSS: Density of spikelets per spike; PH (cm): Plant height;</p>2<p>Hgw_Hgn: high TGW and high NGS group; Hgw_Lgn: high TGW but low NGS group; Lgw_Hgn: low TGW but high NGS group; Lgw_Lgn: low TGW and low NGS group. The sign meanings are consistent in other table;</p>3<p>Group means with the same letter are not significantly different;</p>4<p>Grain weight indicates grouping based on TGW, namely high TGW (including Hgw_Hgn and Hgw_Lgn) and low TGW (including Lgw_Hgn and Lgw_Lgn); Grain number indicates grouping based on NGS, namely high NGS (including Hgw_Hgn and Lgw_Hgn) and low NGS (including Hgw_Lgn and Lgw_Lgn).</p

Numbers and environmental interaction effects of QTLs for yield associated traits in wheat DH lines.

1<p>YP (g): Yield per plant; NSP: Number of spikes per plant; NGS: Number of grains per spike; TGW (g): 1000-grain weight; TNSS: Total number of spikelets per spike; NSSS: Number of sterile spikelets per spike; PFSS: Proportion of fertile spikelets per spike; SL (cm): Spike length; DSS: Density of spikelets per spike; PH (cm): Plant height;</p>2<p><i>a</i>: additive main effects; <i>aa</i>: epistatic main effects; <i>ae</i>: additive environment interaction effects; <i>aae</i>: epistatic environment interaction effects;</p>3<p>Effects: the mean of absolute additive main effects (<i>a</i>)/the mean of absolute additive environment interaction effects (<i>ae</i>);</p>4<p>PVE: the mean of phenotypic variations explained by additive main effects (<i>a</i>)/the mean of phenotypic variations explained by additive environment interaction effects (<i>ae</i>); the same Effects and PVE for <i>aa</i>/<i>aae</i>.</p

Pearson's correlation coefficients between yield-associated traits in wheat DH lines grown in the different environments.

1<p>YP (g): Yield per plant; NSP: Number of spikes per plant; NGS: Number of grains per spike; TGW (g): 1000-grain weight; TNSS: Total number of spikelets per spike; NSSS: Number of sterile spikelets per spike; PFSS: Proportion of fertile spikelets per spike; SL (cm): Spike length; DSS: Density of spikelets per spike; PH (cm): Plant height;</p>2<p>*, **, ***, ****, significant at <i>P</i><0.05, <i>P</i><0.01, <i>P</i><0.005 and <i>P</i><0.0001, respectively; Correlation coefficients between the averaged yield-associated traits are shown on top; Of each correlation pair, the first and the second values are the minimum and maximum correlation coefficient values among 14 (for YP) to 23 (for TGW) environments tested, respectively.</p

Distributions of QTLs for yield associated traits in wheat DH lines across chromosomes.

1<p>YP (g): Yield per plant; NSP: Number of spikes per plant; NGS: Number of grains per spike; TGW (g): 1000-grain weight; TNSS: Total number of spikelets per spike; NSSS: Number of sterile spikelets per spike; PFSS: Proportion of fertile spikelets per spike; SL (cm): Spike length; DSS: Density of spikelets per spike; PH (cm): Plant height.</p

Major QTLs in wheat DH lines.

1<p>YP (g): Yield per plant; NSP: Number of spikes per plant; NGS: Number of grains per spike; TGW (g): 1000-grain weight; TNSS: Total number of spikelets per spike; NSSS: Number of sterile spikelets per spike; PFSS: Proportion of fertile spikelets per spike; SL (cm): Spike length; DSS: Density of spikelets per spike; PH (cm): Plant height;</p>2<p>QTLs in bold were clustered with other QTLs in the same region;</p>3<p>Underlined indicates that the QTL has environmental interaction effects;</p>4<p>The additive main effects (<i>a</i>) of QTL, a positive value indicates that Hanxuan 10 contributes allele to increase the trait, and a negative value means that Lumai 14 provides allele to increase the trait;</p>5<p>Parent contributing the allele increasing QTL trait value;</p>6<p>Increase relative to the population mean;</p>7<p>Total increases in ratio over the population mean.</p

Phenotypic variation explained (PVE) by different genetic components for yield-associated traits in wheat DH lines.

<p>Phenotypic variation explained (PVE) by different genetic components for yield-associated traits in wheat DH lines.</p