Germination and Seedling Parameters of Wheat as Affected by Storage Conditions

A storage experiment was carried out from 27th April to 27thDecember, 2019 to study the effect of storage conditions i.e. methods (open air, under sunshade and in stores), packages type (normal, gunny, polyethylene and metal containers) and periods of seeds fumigation with phosphine (15, 30 and 45 days) on germination and seedling parameters of wheat. The experiment was arranged in a factorial experiment in randomized complete block design (R.C.B.D.) with four replications. Stored wheat seeds under sunshade produced the highest values of final germination percentage, germination index, mean germination time, plumule length, radical length, seedling vigor index and seedlings dry weight, followed by stored wheat seeds in stores. The highest germination index, mean germination time, plumule and radical lengths, seedling vigor index and seedlings dry weight were recorded in the samples of wheat seeds sealed stored in metal containers, followed by normal stored in gunny packages. The highest percentage of final germination was obtained by normal stored in gunny packages, followed by sealing storage in metal containers. The highest final germination percentage, germination index, mean germination time, plumule length, radical length, seedling vigor index and seedlings dry weight and the lowest abnormal seedlings percentage, rotten and sold seeds percentages, speed germination index, co-efficient of germination and germination energy percentage were recorded when treated with phosphine at the rate of 3 tablets/m3after 15 days from beginning the storage. This study recommended that stored wheat seeds under sunshade in metal packages and treating with phosphine at the rate of 3 tablets/m3 after 15 days from beginning the storage to enhance germination and seedlings parameter of wheat under the environmental conditions of Dakahlia Governorate, Egypt.

Analysis of Stored Wheat Grain-Associated Microbiota Reveals Biocontrol Activity among Microorganisms against Mycotoxigenic Fungi

Wheat grains are colonized by complex microbial communities that have the potential to affect seed quality and susceptibility to disease. Some of the beneficial microbes in these communities have been shown to protect plants against pathogens through antagonism. We evaluated the role of the microbiome in seed health: in particular, against mycotoxin-producing fungi. Amplicon sequencing was used to characterize the seed microbiome and determine if epiphytes and endophytes differ in their fungal and bacterial diversity and community composition. We then isolated culturable fungal and bacterial species and evaluated their antagonistic activity against mycotoxigenic fungi. The most prevalent taxa were found to be shared between the epiphytic and endophytic microbiota of stored wheat seeds. Among the isolated bacteria, Bacillus strains exhibited strong antagonistic properties against fungal pathogens with noteworthy fungal load reduction in wheat grain samples of up to a 3.59 log10 CFU/g compared to untreated controls. We also found that a strain of the yeast, Rhodotorula glutinis, isolated from wheat grains, degrades and/or metabolizes aflatoxin B1, one of the most dangerous mycotoxins that negatively affects physiological processes in animals and humans. The mycotoxin level in grain samples was significantly reduced up to 65% in the presence of the yeast strain, compared to the untreated control. Our study demonstrates that stored wheat grains are a rich source of bacterial and yeast antagonists with strong inhibitory and biodegradation potential against mycotoxigenic fungi and the mycotoxins they produce, respectively. Utilization of these antagonistic microorganisms may help reduce fungal and mycotoxin contamination, and potentially replace traditionally used synthetic chemicals.