| dc.description.abstract | An experiment was conducted at the Department of Genetics and Plant Breeding
Laboratory of Hajee Mohammad Danesh Science and Technology University, Dinajpur
during Aman season of 2017. Here, twenty five rice genotypes including 20 land races
were screened to investigate them against different levels of osmotic stress on
germination and seedling morphological characteristics. The osmotic stress conditions
were created in laboratory conditions using three different treatments of Mannitol
(C6H14O6) with a control such as water potential (Ψ) i.e., 0, -5, -10, and -15 bars. The
experiment was laid out in completely randomized design (CRD) with three replications.
Several parameters such as germination percentage, germination rate, seedling vigor
index, number of roots, shoot length, root length, total length of the plant, shoot fresh
weight, root fresh weight, total fresh weight, root dry weight, shoot dry weight and total
dry weight were studied. Most of the traits were evaluated at 14 days after sowing of
seeds on all experimental genotypes. The genotypes differed significantly for all traits.
Furthermore, the treatment effects were also significant for all studied traits. It was
revealed that with decrease of water potential germination percentage, germination rate,
seedling vigor index, number of roots, shoot length, root length, total length of the plant,
shoot fresh weight, root fresh weight, total fresh weight, root dry weight, shoot dry
weight and total dry weight were decreased in most of the genotypes. According to some
genetic parameter studied, there was significant variability existed among the genotypes
for the all characters. Here, high heritability along with high magnitude of genetic
advance in percentage of mean was recorded among most of the traits. Considering all
the characters for all genotypes when these raised in vitro up to seedling stage without
any drought stress (T0), it was found that the genotype BRRIdhan71 stood first position
in performance and was closely followed by Manikmodhu, Laxmilata. When these
genotypes were exposed under low moisture stress (T1), the genotype BRRI dhan71
showed superior performance among other genotypes in respect of all the traits, which
was followed by Begunbahar, Kadamoni Burikatari. In ease of mild moisture stress (T2),
the genotype Burikatari exhibited greater performance for all studied traits that was
followed by BRRI dhan71, Begunbahar. When the genotypes exposed to severe stress
conditions (T3), it was observed that the genotype Burikatari performed best among all
the genotypes for maximum germination percentage, seedling vigor index shoot length,
root length, number of roots, fresh shoot weight, dry root weight and total length.
According to the ranking based on all treatments and studied traits, the genotypes
Burikatari and Begunbahar were found as superior among the all genotypes. These
landraces could be designated as drought tolerant from the study it. This finding could be
confirmed by further in vivo or field condition research as well as marker assisted
breeding research. Therefore, Burikatari and Begunbahar could be helpful to find out
drought tolerant gene and to develop drought tolerant variety. | en_US |
