Abstract:
Soil salinity is one of the most important abiotic stresses that limit crop production.
Responses of six breeding lines (J3D-7755. BD-7757, RD-9008, BD-901 I, BD-10122,
)3D-10123 which were named as GI, 62.03,04. 05 and 66 respectively) of tomato
(Solanurn lycopersicun: I.) to NaCl stress were studied in callus induction. Hypocotyl
and cotyledon segments were chosen as explants for callus induction in vitro. The six
investigated tomato genotypes differed in their callus growth. Tomato seeds were
cultured for callus formation and that callus were treated with 0 mM (control), 50 mM,
100 mM, 150 mM and 200 mM NaCl in nutrient solutions. The effect of the stress
applied on the callus was evaluated in 10 DAT (Days After Treatment) and 17 DAT.
Different concentrations of NaCl in the medium significantly affected the hiomass
callus size and callus weight of tomato. 02 and 06 showed excellent performance of
tolerance up to 50 mM of NaCl. 06 showed better performance under high salt
concentrations i.e., at 100 mM and 200 mM but not at low salt stress. It indicates the
expression of functional gene occurs at high salt stress. However it is possible to select
callus line tolerant to elevated levels of NaCI stress by sudden exposure to high of
NaCl. accordingly a NaCl tolerant cell line was selected from hypocotyls and cotyledon
derived callus of tomato which proved to he a true cell line variant. The interaction
effect of variety and treatment revealed that genotype 06 and GI were the highcst and
lowest performer respectively. These findings indicated some salt tolerant tomato
genotypes which will be promising for regeneration and for future breeding program. It
is quiet necessary to asses accumulation of proline and the anti-oxidant enzymes like
Super Oxide Dismutase, Ascorhatc Pcroxidase and Catalase from the control and
stressed callus as they are the indicator of salt tolerance. It is evident that tissue culture
technique was able to evaluate several genotypes for salt tolerance into cell level under
controlled environment with relatively littLe space and less time required comparing
with such process studies at the whole plant level.
Description:
A Thesis
Submitted to the Faculty of Agriculture
Sher-e-Bangla Agricultural University, Dhaka,
in partial fulfillment of the requirements
for the degree of
MASTER OF SCIENCE
IN
GENETICS AND PLANT BREEDING
SEMESTER: JANUARY-JUNE, 2014