Try this:

$qualification = new Qualification(array (
'level_of_education' => $input['level_educationText'], 
'exam_title' => $input['exam_titleText'], 
'institute_name' => $input['institute_nameText'], 
'insOther' => $input['insOtherText'], 
'result' => $input['resultText'], 
'year_of_passing' => $input['year_passingText'], 
'duration' => $input['durationText'], 
'achievement' => $input['achievementText'] 
) );

$jobseeker->qualifications()->save($qualification);

And considering you have $fillable member defined, you should be able to just pass $input array directly to Qualification constructor:

$qualification = new Qualification( $input );

$jobseeker->qualifications()->save($qualification);