Morphological and Phenological Attributes of Maize Affected by Different Tillage Practices and Varied Sowing Methods

To check the performance of maize under different tillage practices and varied sowing methods, an experiment was conducted at Agronomic Research Area, University of Agriculture, Faisalabad. The experiment was carried out in a randomized complete block design (RCBD) with split plot arrangement with three replications. Different tillage practices viz, conventional tillage, minimum tillage and deep tillage were kept in main plots while sowing methods viz, flat sowing, ridge sowing and bed sowing were allocated to subplots. The maize hybrid “Pioneer-32T16” was sown on 24th February, 2012. Data pertaining to morphological and phenological attributes of maize showed that tillage practices and sowing methods had a significant effect on Germination count·m-2 (7.8), leaf area per plant (5010 cm2), leaf area index (4.87), crop growth rate (20.69 g·m-2·d-1), plant height (213.04 cm), number of leaves per plant (11.89), days to 50% tasseling (72.44) and days to 50% silking (73.77). Economically, maize sown on ridges under deep tillage gave maximum net income of Rs. 85162 ha-1 while minimum net income of Rs. 56984 ha-1 was found where flat sowing was adopted under minimum tillage system and also more BCR of 1.70 was recorded in ridge sown maize under deep tillage.

Phyto-Toxicity of Chromium in Maize： Oxidative Damage, Osmolyte Accumulation, Anti-Oxidative Defense and Chromium Uptake

Agricultural production systems are immensely exposed to different environmental stresses in which heavy metal stress receives serious concerns. This study was conducted to explore the deleterious effects of different chromium （Cr） stress levels, i.e., O, 30, 60, 90, 120, and 150 μmol L^-1, on two maize genotypes, Wandan 13 and Runnong 35. Both genotypes were evaluated by measuring their growth and yield characteristics, Cr accumulation in different plant tissues, alterations in osmolyte accumulation, generation of reactive oxygen species （ROS）, and anti-oxidative enzyme activity to scavenge ROS. The results showed that Cr stress decreased the leaf area, cob formation, 100-grain weight, shoot fresh biomass, and yield formation, while Cr accumulation in different maize tissues was found in the order of roots 〉 leaves 〉 stem ~ seeds in both genotypes. The increased Cr toxicity resulted in higher free proline, soluble sugars and total phenolic contents, and lower soluble protein contents. However, enhanced lipid peroxidation was noticed in the forms of malondialdehyde, hydrogen peroxide （H2O2） and thiobarbituric acid reactive substance accumulation, and electrolyte leakage. The hyperactivity of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, especially glutathione peroxidase and glutathione reductase indicated that these anti-oxidative enzymes had a central role in protecting maize from Cr toxicity, especially for Wandan 13. Moreover, higher uptake and less translocation of Cr contents into the grains of Wandan 13 implied its importance as a potential candidate against soil Cr pollution.