Maize grain yield enhancement in modern hybrids associated with greater stalk lodging resistance at a high planting density: a case study in northeast China.

Lodging resistance is a critical trait in modern maize breeding. This study aimed to examine maize stalk lodging and its related characteristics in response to increasing planting densities in modern hybrids. A two-year field trial was conducted from 2018 to 2019 with two widely grown commercial hybrids ('Xy335' and 'Fm985') and three planting density treatments of 4.5 × 104 (low density, LD), 6.5 × 104 (medium density, MD), and 8.5 × 104 plants/ha (high density, HD). New hybrid Fm985 had a significantly higher grain yield and lower lodging rate at HD, while there was no significance at LD and MD. Compared to Fm985, old hybrid Xy335 had a significantly high plant height, ear and gravity height, and culm length (CL) across the three planting densities, while opposite stalk bending strength (SBS), dry weight per unit length (DWPU), cross-sectional area, and the cellulose and lignin content in the basal internode were low. Correlation and path analysis revealed that kernel number per ear and lodging rate directly contributed to maize grain yield, while lodging-related traits of SBS, stem lignin, and DWPU had an indirect effect on maize grain yield, suggesting that modern hybrid maize yield enhancement is associated with greater stalk lodging resistance at a high planting density in northeast China.

Facile preparation and dual catalytic activity of copper(I)-metallosalen coordination polymers.

Three copper(i)-metallosalen coordination polymers (CPs), {[Ni(II)(SalImCy)]2(Cu(I)CN)9}n (1), {[Cu(II)(SalImCy)]2(Cu(I)CN)9}n (2) and {[Ni(II)(SalImCy)](Cu(I)I)2·DMF}n (3) were prepared by direct combination of Ni(II)/Cu(II)(salen) motifs with [Cu(I)CN]n chains and Cu2I2 clusters via the metalloligand strategy. The mixed-valence and mixed-metal CPs could effectively catalyze both the oxidation of aromatic alcohols to ketones and aldehydes under mild conditions and photocatalytic degradation of organic dye methylene blue (MB). This work demonstrates the effective integration of transition metal catalytic Ni(II)/Cu(II)(salen) units and photoactive copper(i) species in a single solid polymer to meet the demand for catalytic materials with the dual catalytic properties.