Abstract:
Four of Xanthomonas oryzae pv. oryzae isolates viz. Iso1 to Iso4 were isolated
from different diseased samples collected from BRRI during T. Aman 2019
season. Isolates phenotypic characters e.g, colony color, shape, growth patterns
were examined and found similar. Typical slimy and cream colored bacterial
growth was observed in peptone sucrose agar medium for all four isolates.
Molecular markers were used to confirm the Xanthomonas oryzae pv. oryzae
isolates and two isolates namely Iso1 and Iso4 were confirmed as Xoo. Five BLB
resistant advanced breeding lines, P-3-58, P-5-1, P-7-70, P-7-82 and P-8-78 were
tested against Xoo with susceptible check variety Purbachi and all five advanced
lines showed resistance reaction. These five advanced lines were molecularly
screened for four BLB resistance genes Xa4, xa5, xa13 and Xa21using four
molecular markers MP, xa5 Multiplex, xa13-prom and pTA248. Among the
advanced lines, P-5-1, P-7-70, P-7-82 and P-8-78 possessed Xa4 gene and P-358,
P-5-1,
P-7-70 and P-8-78 possessed xa5 gene. A field experiment was set
with five advanced lines along with one susceptible check (Purbachi) and two
standard checks (BRRI dhan39 and BRRI dhan49) to find out the BLB resistant
advanced line. All the selected lines showed good performance in terms of BLB
resistance and yield. The highest yield (3.32 t ha
ix
-1
) was recorded in P-7-70.
Considering all other agronomic traits and resistance reaction, P-7-70 line can
be used in further BLB resistance variety development programs.
