Recurrent Selection to Alter Grain Phytic Acid Concentration and Iron Bioavailability

Iron is an important micronutrient and Fe deficiency is a global health concern. Phytic acid inhibits Fe absorption and cannot be digested by monogastric livestock or humans. High phytate concentration in staple crops may be one of the contributing factors for the high incidence of anemia in developing countries because of its inhibiting effect on Fe absorption. In seeds, it serves as the main storage compound for P. Low phytic acid mutants (lpa) in maize (Zea mays L.) have improved Fe bioavailability, but they have poor germination. Our objective was to develop both low phytic acid (LPA) and high phytic acid (HPA) maize populations using recurrent selection and to compare seed quality and Fe bioavailability among the HPA and LPA populations and lpa mutant lines. Three cycles of selection were performed in two broad-based synthetic populations, BS11 and BS31. The resulting HPA and LPA populations were significantly different in phytic acid concentration in the BS11-derived populations (P \u3c 0.05) but not in the BSS31-derived populations (P \u3e 0.05). The BS11LPA maize population had improved seed germination (13–16%; P \u3c 0.05), and Fe bioavailability was not statistically different (P \u3e 0.05) than the lpa mutant inbred lines. We conclude that recurrent selection for phytic acid levels may be a viable approach for improving Fe bioavailability of grain while maintaining seed quality

In-situ epitaxial growth of superconducting La-based bilayer cuprate thin films

We investigate the epitaxial growth of bilayer cuprate La2CaCu2O6+\delta using pure ozone as an oxidant, and find that even the crystal with parent composition without cation substitution can show metallic behavior with the aid of epitaxial strain effect. The hole concentration is controlled simply by excess-oxygen doping, and the films grown under the optimum conditions exhibit superconductivity below 30 K. This is the first result on the superconductivity of bilayer La2CaCu2O6+\delta induced purely by the excess oxygen.Comment: 5 pages, 3 figures, To appear in Phys. Rev. B, Rapid Communication

Spin, charge and orbital ordering in ferrimagnetic insulator YBaMn2_2O5_5

The oxygen-deficient (double) perovskite YBaMn$_2$O$_5$, containing corner-linked MnO$_5$ square pyramids, is found to exhibit ferrimagnetic ordering in its ground state. In the present work we report generalized-gradient-corrected, relativistic first-principles full-potential density-functional calculations performed on YBaMn$_2$O$_5$ in the nonmagnetic, ferromagnetic and ferrimagnetic states. The charge, orbital and spin orderings are explained with site-, angular momentum- and orbital-projected density of states, charge-density plots, electronic structure and total energy studies. YBaMn$_2$O$_5$ is found to stabilize in a G-type ferrimagnetic state in accordance with experimental results. The experimentally observed insulating behavior appears only when we include ferrimagnetic ordering in our calculation. We observed significant optical anisotropy in this material originating from the combined effect of ferrimagnetic ordering and crystal field splitting. In order to gain knowledge about the presence of different valence states for Mn in YBaMn$_2$O$_5$ we have calculated $K$-edge x-ray absorption near-edge spectra for the Mn and O atoms. The presence of the different valence states for Mn is clearly established from the x-ray absorption near-edge spectra, hyperfine field parameters and the magnetic properties study. Among the experimentally proposed structures, the recently reported description based on $P$4/$nmm$ is found to represent the stable structure

Maintenance of sorghum (Sorghum bicolor, Poaceae) landrace diversity by farmers's election in Ethiopia

We quantitatively examined the relationships between Sorghum landrace diversity at the field level and environmental factors and farmers’ selection practices in north Shewa and south Welo regions of Ethiopia. Surveys were conducted on 260 randomly selected farmers’ fields. The altitude and size of each field were recorded. Sorghum plants at 5 m intervals along transect lines spaced 10 m apart over each field were identified by the farmers and the owner of each field was asked why she/he decided to grow each plant. Soil samples were collected from all of the fields and analyzed for pH, organic content, and sand, silt and clay content. Simple and polynomial regressions and multiple regression analyses showed that Sorghum landrace diversity at the field level had significant relationships with the number of selection criteria used by the farmers, field altitude, field size, pH and clay content. As the number of selection criteria increased, landrace diversity in the fields increased. This relationship was not a result of the correlation between selection criteria and the environmental factors, because it was significant after statistically correcting for the effects of the environmental variables. This study quantitatively confirms the role of traditional farmers in the maintenance of sorghum landrace diversity in north Shewa and south Welo regions of Ethiopia

Sorghum [Sorghum bicolor (L.) Moench] landrace variation and classification in North Shewa and South Welo, Ethiopia

Fourteen phenotypic characters were chosen for the purpose of obtaining taxonomic evidence on the resemblances of 177 accessions of sorghum from North Shewa and South Welo regions of Ethiopia. Canonical Discriminant Analysis (CDA) and Modeclus cluster analysis were conducted to see if the 177 accessions could form clusters based on their morphological characters, and to test the consistency of farmers’ naming of the five most common Sorghum landraces represented by 44 accessions. Multivariate analyses grouped the 177 accessions into three clusters linked by a few phenotypic intermediate landraces. A botanical key was established for easy classification of the Sorghum crop plants grown in the study area. The number of accessions of the five most common landraces named by the farmers formed dissimilar groups, suggesting that farmers’ naming of these Sorghum landraces are consistent. Midrib color, grain color, grain size, glume color, glume hairiness, and grain shape were the leading morphological characters used by the farmers in naming these Sorghum landraces

Maintenance of Sorghum (Sorghum bicolor, Poaceae) landrace diversity by farmers' selection in Ethiopia

We quantitatively examined the relationships between Sorghum landrace diversity at the field level and environmental factors and farmers’ selection practices in north Shewa and south Welo regions of Ethiopia. Surveys were conducted on 260 randomly selected farmers’ fields. The altitude and size of each field were recorded. Sorghum plants at 5 m intervals along transect lines spaced 10 m apart over each field were identified by the farmers and the owner of each field was asked why she/he decided to grow each plant. Soil samples were collected from all of the fields and analyzed for pH, organic content, and sand, silt and clay content. Simple and polynomial regressions and multiple regression analyses showed that Sorghum landrace diversity at the field level had significant relationships with the number of selection criteria used by the farmers, field altitude, field size, pH and clay content. As the number of selection criteria increased, landrace diversity in the fields increased. This relationship was not a result of the correlation between selection criteria and the environmental factors, because it was significant after statistically correcting for the effects of the environmental variables. This study quantitatively confirms the role of traditional farmers in the maintenance of sorghum landrace diversity in north Shewa and south Welo regions of Ethiopia