Abstract
Five set of experiments were conducted during 2013-2017 seasons for assessing the
variation in morphological, physiological, biochemical and molecular characters,
genotype x environment interaction and yield of rapeseed-mustard genotypes to
identify suitable genotypes for coastal saline area. One hundred and one rapeseedmustard genotypes were screened in pot culture using Hoagland nutrition media at
four different salinity concentration and identified 14 genotypes as tolerant on the
basis of the ability of dry mass production under 12dS/m salinity. Molecular
diversity of twenty five selected rapeseed-mustard genotypes of different categories
obtained from previous study were evaluated using SSR marker and found
considerable diversity of breeding value among the genotypes. Higher ratio of
genetic diversity was obtained in B. rapa genotypes than in B. napus and B. juncea
genotypes. The crop characters of that 25 selected rapeseed-mustard genotypes like
days to germination, plant height, number of branch/plant, leaf area, days to
flowering, days to maturity, number of siliqua/plant, length of siliqua, number of
seeds/siliqua, 1000 seed weight and seed yield/plant were studied in pot culture
using soil as growing media and found wide range of variation among the genotypes
for all characters. Genotypes BD-7104, Jun-536, BD-6950 and BD-10115 were
identified as tolerant, BJDH-12 and BARI sarisha-16 as moderately tolerant and
finally BARI sarisha-11, Nap-0564 and JBC-05117 along with rest other 16 genotypes
as susceptible at 12dS/m salinity on basis of the ability of relative yield performance.
In the following study 13 selected rapeseed-mustard genotypes were then assessed in
three different environment; in the field lab of Oil Seed Research Centre, BARI,
Gazipur, Agriculture Research Station, Benarpota, Satkhira and multi locations yield
trial site, On Farm Research division, Koyra, Khulna to know the adaptability and
stability using pool analysis, AMMI and GGE biplot method. Genotypes BD-6950
and BD-7104 found stable, adaptable and high yielding across all three Environment.
Finally mechanism of Salinity tolerance of BD-6950 and BD-7104 were confirmed by
studying thirteen different physiological and biochemical parameters comparing
with susceptible genotype BD-7114. It was found that tolerant genotypes maintained
higher proline and chlorophyll content over the susceptible genotype in all salinity
level. Considerable variation in Na+, K+, Ca2+ and Mg2+ content of root, shoot, leaf,
seed and hull were observed among tolerant and susceptible genotypes at all salinity
level. Another two important physiological parameters Methyl glyoxal (MG) and
reactive oxygen species hydrogen peroxide (H202) production was found higher in
susceptible genotype BD-7114 compared to tolerant genotypes BD-6950 and BD-7104
in all salinity levels. Opposite trend was noticed in Gly I and Gly 2 enzyme system
for detoxifying MG and also antioxidant enzymes like APX, POD and CAT activity
of leaf to detoxifying the adverse effect of reactive oxygen species.