تأثير بعض عزلات الفطر Aspergillus niger على تعفن أبصال البصل Onion (Allium capa L.)‎ و مقاومتها بالمستخلص المائي الحار للزنجبيل Ginger

Abstract EN

Pathogenicity test of 13 isolates of A.niger on onion bulbs revealed that all tested of onion cultivars, Texas Early Grano (TEG) , Early White Grano (EWG) and Red Baron (RB) , were susceptible to all tested isolates .

However, the isolate 3 was the most distrutivars isolate that caused diagonal damage on bulbs that reached 4.29 cm .

while the EWG was a highly effected cultivars by all isolates , the mean diagonal damage was 2.19 cm during of 4 weeks.

Exudates of A.niger isolates also had the ability to rot bulbs and caused diagonal damage, the isolate 7 caused highly affected diagonal damage of 4.19 cm, while the cultivar RB was the most affected cultivar by all tested isolates,the diagonal damage mean of this cultivars was 2.17 cm .

The isolate 3, among all tested isolates, was the most pathogenicity of all cultivars.

Also the result of dipping of bulbs in a hot extract of ginger for 5 minutes showed decreasing in bulbs infection by blak rot rot .

Isolate 3 had the ability to produce ochratoxin , aflatoxin B1 and aflatoxin B2 in the infected bulbs , the ochratoxin had the highest concentration in infected parts reaching to 1.129 mg.ml-1.

The non-infected part of bulb, showed containing of ochratoxin, aflatoxin B1 and aflatoxin B2 at concentrations of 0.449 , 0.188 and 0.162 mg.ml-1 , respectively .