‘Nachit’, a wild-relative-derived durum wheat resilient to climate change in Morocco

Morocco, in North Africa, is a country vastly exposed to the whims of climate change,with frequent moisture and heat stresses occurring throughout the season. Hence,developing climate-resilient, high-yielding, and nutritious cultivars of durum wheat[Triticum turgidumL.durum(Desf.)] is a major goal and challenge of Moroccancrop breeders. In that sense, the exploitation of crop wild relatives (CWRs) holdsgreat potential to increase genetic diversity for critical adaptation traits. ‘Nachit’(Reg. no. CV-1202, PI 702365) is a CWR-derived durum wheat cultivar releasedin 2018 for cultivation in Morocco by a joint effort of the National Institute of Agro-nomic Research, Morocco and the International Center for Agricultural Research inthe Dry Areas. Nachit was released due to its good adaptation to the Moroccan dryconditions combined with high yield potential under irrigated conditions, extremelylarge grains, and richness in protein content. It also combines several traits for droughttolerance such as earliness and deep root system. Nachit was derived from a top crossbetween two elite lines and a wild emmer [T. turgidumssp.dicoccoides] collected inSyria. Hence, it provides a substantial example of exploitation of CWRs to achieve asuperior cultivar adapted to the climatic stresses and responding to human needs

A panel of elite accessions of durum wheat (Triticum durum Desf.) suitable for association mapping studies

Abstract The effectiveness of association mapping (AM) based on linkage disequilibrium (LD) is currently being tested in a number of crops. An important prerequisite for the application of AM is the availability of collections of accessions with a suitable level of genetic variation for target traits and with limited spurious LD due to the presence of population structure. Herein, the results of a genomewide molecular characterization of a collection of elite durum wheat accessions well-adapted to Mediterranean environments are presented. Ninety-seven highly polymorphic simple sequence repeats and 166 amplified fragment length polymorphism markers were used to characterize 189 durum accessions, mainly cultivars and advanced breeding lines. Genome-wide significant and sizeable LD indices at a centimorgan scale were observed, while LD mainly decayed within 10 cM. On the other hand, effects due to spurious LD were notably lower than those previously observed in a durum wheat collection sampling durum gene pools of more diverse origin. These results, coupled with the high level of genetic variability detected for a number of important morpho-physiological traits and their high heritability, indicate the suitability of this collection for AM studies targeting agronomically important traits

Quantitative Trait Loci for Grain Yield and Adaptation of Durum Wheat (Triticum durum Desf.) Across a Wide Range of Water Availability

Grain yield is a major goal for the improvement of durum wheat, particularly in drought-prone areas. In this study, the genetic basis of grain yield (GY), heading date (HD), and plant height (PH) was investigated in a durum wheat population of 249 recombinant inbred lines evaluated in 16 environments (10 rainfed and 6 irrigated) characterized by a broad range of water availability and GY (from 5.6 to 58.8 q ha−1). Among the 16 quantitative trait loci (QTL) that affected GY, two major QTL on chromosomes 2BL and 3BS showed significant effects in 8 and 7 environments, with R2 values of 21.5 and 13.8% (mean data of all 16 environments), respectively. In both cases, extensive overlap was observed between the LOD profiles of GY and PH, but not with those for HD. QTL specific for PH were identified on chromosomes 1BS, 3AL, and 7AS. Additionally, three major QTL for HD on chromosomes 2AS, 2BL, and 7BS showed limited or no effects on GY. For both PH and GY, notable epistasis between the chromosome 2BL and 3BS QTL was detected across several environments