Assessing Genetic Diversity to Breed Competitive Biofortified Wheat With Enhanced Grain Zn and Fe Concentrations

Abstract

Breeding wheat with enhanced levels of grain zinc (Zn) and iron (Fe) is a cost-effective, sustainable solution to malnutrition problems. Modern wheat varieties have limited variation in grain Zn and Fe, but large-scale screening has identified high levels of Zn and Fe in wild relatives and progenitors of cultivated wheat. The most promising sources of high Zn and Fe are einkorn (Triticum monococcum), wild emmer (T. dicoccoides), diploid progenitors of hexaploid wheat (such as Aegilops tauschii), T. spelta, T. polonicum, and landraces of T. aestivum. This study evaluate the effects of translocations from rye and different Aegilops species in a “Pavon-76” wheat genetic background and utilized in the wheat biofortification breeding program at CIMMYT that uses diverse genetic resources, including landraces, recreated synthetic hexaploids, T. spelta and pre-breeding lines. Four translocations were identified that resulted significantly higher Zn content in “Pavon 76” genetic background than the check varieties, and they had increased levels of grain Fe as well-compared to “Pavon 76.” These lines were also included in the breeding program aimed to develop advanced high Zn breeding lines. Advanced lines derived from diverse crosses were screened under Zn-enriched soil conditions in Mexico during the 2017 and 2018 seasons. The Zn content of the grain was ranging from 35 to 69 mg/kg during 2017 and 38 to 72 mg/kg during 2018. Meanwhile grain Fe ranged from 30 to 43 mg/kg during 2017 and 32 to 52 mg/kg during 2018. A highly significant positive correlation was found between Zn and Fe (r = 0.54; P < 0.001) content of the breeding lines, therefore it was possible to breed for both properties in parallel. Yield testing of the advanced lines showed that 15% (2017) and 24% (2018) of the lines achieved 95–110% yield potential of the commercial checks and also had 12 mg/kg advantage in the Zn content suggesting that greater genetic gains and farmer-preferred wheat varieties were developed and deployed. A decade of research and breeding efforts led to the selection of “best-bet” breeding lines and the release of eight biofortified wheat varieties in target regions of South Asia and in Mexico.

Organic Cropping System Affects Grain Chemical Composition, Rheological and Agronomic Performance of Durum Wheat

“…The wide genetic variability found for Fe and Zn represents an important result in terms of breeding program, since the modern varieties have limited variation [47]. Therefore, this gene pool could be investigated for future QTL mapping and breeding biofortified wheat [47,48]. In relation to the macro-mineral elements, the significant highest and lowest contents were found in 'Saragolla' and 'Core' (425 and 233 mg kg −1 of FW) for Ca, 'Duilio', and 'Ramirez' (5200 and 3148 mg kg −1 of FW) for K, 'Tirex', and 'Ramirez' (1663 and 1295 mg kg −1 of FW) for Mg, and 'Tirex', and 'Duilio' (4071 and 1511 mg kg −1 of FW) for P (Tables 4 and 8).…”

Comparative analysis of perennial and annualPhaseolusseed nutrient concentrations

“…In recent years attention has focused in part on the possible development of perennial, herbaceous crops [11], [13], [14], [64] . Expanding development of species such as wild, perennial legumes, into an agroforestry system offers opportunities to enhance food production and possibly reduce the risk of nutrient deficiencies [6], [7], [65], [66] . In this study, we explored differences in nutrient content among perennial and annual wild species of the common bean genus Phaseolus , an important first step towards identifying Phaseolus species that might be good candidates for pre-breeding and/or inclusion in agroforestry and other agricultural systems.…”

“…Collectively, the growing body of literature on ion covariation suggests that ion concentrations are highly dynamic and therefore it will be important for breeders to determine the ion variation and covariation for each species (and possibly across multiple geographic locations). However, the promise of agricultural crops with optimization of multiple ions is obtainable; recently, iron and zinc have been successfully co-selected for increased concentrations in wheat species [66] .…”

Foliar applied zinc increases yield, zinc concentration, and germination in wheat genotypes

“…The substantial genetic variation present in wheat serves as raw gene pool for the development of biofortified varieties (Garcia‐Oliveira, Chander, Ortiz, Menkir, & Gedil, 2018; Monasterio & Graham, 2000; Velu et al., 2014). A wide range of genetic variation has been identified in wheat genotypes for Zn content (Amiri, Bahraminejad, Sasani, Jalali‐Honarmand, & Fakhri, 2015; Velu et al., 2018). Exploring wheat gene pool at the Genebank of the International Maize and Wheat Improvement Center (CIMMYT, El Batan, México) indicated a several‐fold variation for grain Fe and Zn in disomic hexaploid bread wheat (Velu et al., 2014).…”

“…In other studies, high genetic variation has been identified for Zn concentration in bread wheat cultivars (Abdoli, Esfandiari, Alilloo, Sadeghzadeh, & Mousavi, 2019; Khokhar et al., 2018). Identification of genetic variability among wheat genotypes may assist breeding programs to develop high Zn varieties (Velu et al., 2018).…”