Breeding to increase beta-carotene levels in cereal grains, termed provitamin A biofortification, is an economical approach to address dietary vitamin A deficiency in the developing world. Experimental evidence from association and linkage populations in maize (Zea mays L.) demonstrate that the gene encoding beta-carotene hydroxylase 1 (crtRB1) underlies a principal quantitative trait locus associated with beta-carotene concentration and conversion in maize kernels. crtRB1 alleles associated with reduced transcript expression correlate with higher beta-carotene concentrations. Genetic variation at crtRB1 also affects hydroxylation efficiency among encoded allozymes, as observed by resultant carotenoid profiles in recombinant expression assays. The most favorable crtRB1 alleles, rare in frequency and unique to temperate germplasm, are being introgressed via inexpensive PCR marker-assisted selection into tropical maize germplasm adapted to developing countries, where it is most needed for human health.

Cultivated emmer wheat, Triticum dicoccon Schrank, a tetraploid species with hulled grain, has been largely cultivated during seven millennia in the Middle-East, Central and West Asia, and Europe. It has been largely replaced by hulless species and is now a minor crop, with the exception of some countries like India, Ethiopia and Yemen, where its grain is used for preparing traditional foods. Nutritional qualities and specific taste and flavor of emmer wheat products have led to a recent development of the cultivation in some European countries. Emmer wheat also possesses valuable traits of resistance to pests and diseases and tolerance to abiotic stresses and is increasingly used as a reservoir of useful genes in wheat breeding. In the present article, a review concerning taxonomy, diversity and history of cultivation of emmer wheat is reported. Grain characteristics and valuable agronomic traits are described. Some successful examples of emmer wheat utilization for the development of durum or bread wheat cultivars are examined, and the perspectives in using emmer wheat as health food and for the development of new breeding germplasm are discussed.

Wild wheat (Triticum aestivum L.) relatives could represent a valuable source of genetic variation for improvement of abiotic stress tolerance in cultivated wheat. A better knowledge of the adaptive strategies developed by these species is needed. A collection of 157 Aegilops geniculata accessions originating from different ecogeographical regions was studied during two successive years for several traits related to water status, chlorophyll content, and plant thermal regulation under Mediterranean field conditions. Close association was found between the studied traits and the origin of accessions. Two adaptive strategies were distinguished. Accessions originating from harsh environments had low biomass, low grain production and high water‐use efficiency (low C isotope discrimination). They were early, with small, thick leaves exhibiting low chlorophyll content, high surface temperature and low epidermal transpiration. We suggest that in these accessions, decreased leaf chlorophyll content could limit the energy load from strong sunlight. In accessions originating from regions with a mild Mediterranean climate, thermal regulation of the leaf may rather depend on transpiration, as suggested by high C isotope discrimination values. These accessions also were characterized by high chlorophyll content, leaf area, and biomass production. Associations between the physiological traits observed could help to better understand the relationship between abiotic stress tolerance and yield in cultivated wheats. Results obtained confirmed the potential value of Aegilops geniculata for improvement of high temperature and drought stress tolerance in wheat and could contribute to the choice of traits to be introgressed and the accessions to be used in wide hybridization programs.

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In Europe, wild wheat relatives of the Triticum–Aegilops complex grow in sympatry with cultivated bread wheat (Triticum aestivum L.) and spontaneous hybridization is known to occur. With the development of transgenic wheat, an understanding of the likelihood and occurrence of hybridization and introgression between wheat and its relatives is needed for use in risk assessment. To assess the probability of wheat to wild relative gene introgression, the distribution and biology of wheat wild relatives and their genome affinity and crossability with bread wheat were reviewed. Twelve of the 22 known Aegilops species, as well as one wild Triticum species, T. monococcum L. subsp. aegilopoides (Link) Thell., are known to occur in Europe near or within wheat cultivation. Five tetraploid species, Ae. cylindrica Host., Ae. triuncialis L., Ae. geniculata Roth., Ae. neglecta Req. ex Berthol., and Ae. biuncialis Vis., have wide distribution in most European countries. Bread wheat, wild Aegilops species, and Triticum species are predominantly autogamous (except Ae. speltoides Tausch, typically allogamous), but outcrossing among species is possible depending on species sympatry, concurrent flowering, and sexual compatibility. Spontaneous hybridization with wheat was reported for most of the tetraploid Aegilops species. The probability of gene transfer and gene retention in hybrid progenies is, however, higher when a gene is located on a shared genome, particularly on the D genome shared with Ae. cylindrica and Ae. ventricosa Tausch. Case‐by‐case and region‐by‐region assessments are needed to evaluate the risk associated with production and competitiveness of hybrids and their progeny.

Senescence was evaluated at different stages of the grain‐filling period in eight durum wheat varieties using numerical image analysis (NIA). The varieties were grown under early, severe drought conditions on the high plains of Sétif in Algeria. After flowering, three different irrigation treatments were applied. Treatment effect was small, while a genotypic effect was noted for most of the senescence parameters. Senescence correlated to biomass, while the maximal rate of senescence, Vsmax, correlated to thousand‐kernel weight. The potential of the method of numerical image analysis for monitoring flag leaf senescence, detecting genotypic variability and selecting genotypes with delayed senescence is discussed.

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