Agronomic bio-fortification of iron, zinc and selenium enhance growth, quality and uptake of different sorghum accessions

Agronomic bio-fortification is one of the main approaches for mitigation of micronutrient shortage in human populations and endorses sustainable production of food and feed. Studies related to agronomic bio-fortification of crops are mainly focused on single or rarely two micronutrients application, and no attempt has made to study the combined effect of zinc (Zn), iron (Fe) and selenium (Se) on forage sorghum. Therefore, this research was accomplished to evaluate the effect of Zn, Fe and Se bio-fortification on diverse sorghum accessions. The field experiments were conducted in a randomised complete block design with a split-plot arrangement. The treatments comprised of Zn (10 mg/L as ZnSO₄∙5H₂O), Fe (7 mg/L as FeSO₄∙7H₂O), Se (3 mg/L as SeSO₄) and CK (control) were applied to five sorghum accessions: G₁ (Y-16), G₂ (YSH-166), G₃ (YSH-134), G₄ (YSS-98) and G₅ (YSH-132). According to our results, the sorghum accession G₅ showed superiority over all other accessions and produced maximum values of all growth and quality traits except grains number per panicle and 1 000-grain weight. All applied micronutrients (Zn, Fe and Se) enhanced the growth, quality and uptake of nutrients in sorghum accessions. However, Se recorded the highest plant height, stem diameter, 1 000-grain weight and Zn produced the maximum protein, oil and starch contents. Conclusively, it can be concluded that G₅ with Se must be used to achieve the optimum values of agronomic traits, while G₅ with Zn found more effective to improve the quality traits of sorghum.

New Sources of Resistance in Sorghum (Sorghum bicolor) Germplasm Are Effective Against a Diverse Array of Potyvirus spp.

Sorghum is a host to numerous Potyvirus spp. and its germplasm encompasses a wide range of infection responses to these viruses. We determined how 183 mini-core-collection sorghum germplasm accessions responded to mechanical inoculation with Maize dwarf mosaic virus (MDMV) in growth regimes in which they were maintained at 30°C followed by 16°C for 5 days. Accessions that appeared immune to MDMV in this initial screening were evaluated for their response in a similar temperature maintenance regime to mechanical inoculation with MDMV, Sugarcane mosaic virus strain MDB (SCMV-MDB), Sorghum mosaic virus (SrMV), Zea mosaic virus (ZeMV), and Kansas, Nigerian, and Australian isolates of Johnsongrass mosaic virus (JGMV-KS, -N, and -Aus, respectively). In both experiments, MDMV systemically infected all accessions except international sorghum accession number (IS) 7679 and IS 20740. These accessions also proved resistant to MDMV, SCMV-MDB, SrMV, and JGMV-N but both were susceptible to the JGMV-KS and JGMV-Aus isolates. IS 7679 but not IS 20740 was resistant to infection with ZeMV. These observations suggest that IS 7679 and IS 20740 might serve as new sources of resistance to several Potyvirus spp. that systemically infect sorghum.

Identification of RFLP markers linked to a gene for downy mildew resistance (Sdm) in sorghum

The Sdm locus in sorghum accession SC325 confers resistance to downy mildew caused by pathotypes 1 and 3 of Peronosclerospora sorghi. Restriction fragment length polymorphism linkage analysis placed the Sdm locus near loci detected by probes pSbTXS552 and pSbTXS361 at 5.0 and 7.9 cM, respectively. Fragment patterns for the cross segregating for disease resistance differed from those for the original mapping cross, preventing assignment of Sdm to a linkage group. Keywords: Peronosclerospora sorghi, resistance, RFLP, linkage, hybrid breeding.