Combining QTL Analysis and Genomic Predictions for Four Durum Wheat Populations Under Drought Conditions

Molecular Mapping and Genomics of Grain Yield in Durum Wheat: A Review

“…In addition, the marker “ wPt-5092 ” located on chromosome 7A was concomitantly associated with KNM and GY, with a positive additive effect for both traits. This result is in accordance with Zaïm et al [ 37 ], who detected four QTLs for SNM on chromosomes 1A, 3B, 5B and 6B, explaining between 6.6% and 13.2% of the phenotypic variance. Moreover, four QTLs for SNM were detected on chromosomes 3A, 4B, 6A and 7A, responsible for 14% and 24% of the SNM variance [ 44 ].…”

“…Thus, the genetic basis of GY has been investigated through the three main yield components which will be explored in this review: kernel weight, kernels number and kernels number per unit area [ 28 , 31 ]. A total of 665 QTLs (100 with a pleiotropic effect) were identified and associated with grain yield and its components ( Table S1 ) [ 7 , 14 , 15 , 17 , 18 , 30 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 ]. Specifically, nine additional yield components were considered: kernel length (KL), kernel width (KW), thousand-kernel weight (TKW) associated with the kernel weight, kernels number per spike (KNS), kernels number per spikelet (KNSL), spikelets number per spike (SLNS) associated with the kernels number, grain yield (GY), kernels number per square meter (KNM) and spike number per square meter (SNM) related to the kernels number per unit area ( Figure 1 ).…”

“…Conversely, durum wheat landraces show a much greater variability for kernel size and shape ([ 32 ], and the reference therein). In durum wheat, there is considerably less information of QTLs controlling kernel weight and most studies have been conducted to decipher the genetic basis of TKW [ 33 , 34 , 35 , 36 , 37 ], and fewer studies have been performed to elucidate the genetic basis of kernel size [ 17 , 30 , 32 ]. In this review, a total of 264 QTLs for kernel weight-related traits (201 for TKW, 33 for KL and 30 for KW) were identified on all chromosomes of durum wheat, however, no QTLs were reported for KW on chromosomes 1A and 2B, and for KL on chromosome 1A ( Table S1 , Figure 1 ).…”

“…Finally, the information of previously identified QTLs can be included in genomic prediction models to increase the prediction ability [ 100 ]. In this sense, Zaïm et al [ 37 ] recently increased the precision in the prediction from 0.37 to 0.54 and 0.30 to 0.54, for grain yield and TKW, respectively, when the QTL-underlying markers were fixed in the model. Therefore, a combined approach between associative mapping and genomic selection allows increasing genetic gains for grain yield-related traits in durum wheat breeding programs.…”

From Genetic Maps to QTL Cloning: An Overview for Durum Wheat

“…The accuracy found by these authors ranged from 0.5 to 0.8 for single traits, increasing in multi-traits for grain yield. Zaim et al [ 217 ] used four populations to develop genomic prediction models for grain yield under drought conditions. These authors found that including QTL information from the populations increased the prediction accuracies by 0.06 to 0.12 points.…”