Explanation of the Feilds in TDNA-Seq_1-70K.txt :

chr=chromosome which contains hit

insert position = estimated position of the insert

insert direction = F - Forward (Watson) Strand ; R - Reverse (Crick) Strand; B - Bidirectional insert due to a tandem TDNA insertion 

gene hit = TDNA gene hit (if available). A T-DNA is considered to have  hit a gene if it is found in the transcriptional unit ( 5'utr start - 3'utr stop ).