Potential Impacts of Environmental Conditions, Polyphenolic Compounds and Trypsin Inhibitor Against Ear and Kernel Rots Diseases of Maize

Abstract

Visible ear rot infection (VER), frequency of associated fungi percentages and disease severity rating (DSR) of 25 maize genotypes were affected significantly by the two years . Diseases criterion were higher in the season of 2008 than 2009. VER recorded 26.67 to 46.66% and 3.00 to 11.00% , DSR were ( 5) and (3-4) during the two seasons, respectively, with the most infected maize ones. VER caused significant reduction of yield weight (100 kernels/ g) with most of tested maize genotypes. Fusarium verticillioids (F. moniliforme) was the most frequently isolated phytopathogenic fungus from the seeds of all maize genotypes with higher values especially in season 2008 followed by A. niger, A. flavus and Penicillium sp. The last fungi group recorded high values in 2009 than 2008. High ear rot and fungi frequency values led to significant decrease in germination, especially in the first season. Consequently, ear rot disease was affected by climatic conditions during the period of disease development in August and September for the two tested seasons, here, climatic conditions were more suitable for the disease development and its equerries was determined as recorded high temperature degrees (max) and relative humidity, especially at (13:30 O'clock).The decrement in minimum temperature degrees were clear in season 2008, where the disease increased. That mean, minimum temperature and relative humidity at 13.30 O'clock were more suitable in 2008 than 2009 and played an active role in developing ear rot disease in maize. Quality of some maize genotypes susceptible and resistant to ears and kernels rot were investigated. Results showed that, resistant maize genotypes had the highest values of ether extract, ash, fiber and carbohydrates compared with susceptible ones. On Contrast, the susceptible maize genotypes contained the highest level of crude protein compared to resistant ones. Considerable increase of total, reducing and non-reducing sugars values were recorded with the susceptible maize genotypes than these of resistant ones. On the other hand, susceptible maize genotypes contained lower total phenolics and trypsin inhibitors than the resistant genotypes. SC10 maize genotypes (resistant) had the highest amount of total phenols and trypsin inhibitor compared with other resistant and susceptible ones. In this study corn flours cv.SC10 were separately added at different levels (10,15,20,25) to wheat flour (82٪) for processing balady bread impaling were investigated. The flour were subjected to quality properties examination bread were examined organolepticaly .The obtained results showed that the farinograph and extensogesaph results indicated that , mixing time, arrival time , dough weakening and extensibility increased with increasing the level of adding corn flours add . While stability , resistance to extension and energy decreased when compared with wheat flours control. As for organoleptic properties it was found that the over all acceptabilities were good for all the tested bread .

Effect of Foliar Application of Some Nutrients on Maize Ears Rot Disease, Synthase of Anti-Defense Compounds, Quality of Maize Grains and Bread

“…Concerning dough development time (mixing time), arrival time and weakening dough increased with increasing the addition amount of corn flours. These results are in the same trend with Hegazy (2002), Rizk (2004) and Farahat et al (2010), they found that, the wheat/maize doughs containing either 15 or 20% maize flour showed lower water absorption, mixing time and dough stability as compared to control dough. Dough weakening degrees increased from 100 for control to 110 and 120 BU.…”

“…Many research groups have validated the role of plant trypsin inhibitor (TI) as mean of plant defense against fungal infection (Baker et al, 2009). Chen et al (2007) and Farahat et al (2010) detected that, antifungal trypsin inhibitor proteins was higher in resistant maize lines compared with susceptible ones and caused decreasing of infection by ear rot and associated fungi especially F. moniliforme. TI demonstrated antifunal activity against fungal growth and conidial germination of eight phytopathogenic fungi including F. moniliforme, may be partially due to its inhibition of fungal αamylase activity and production (Chen et al, 1999), limiting the avialibility of simple sugars needed for fungal growth and aflatoxin production (Woloshuk et al, 1997).…”