Abstract
Bangladesh is one of the most vulnerable countries in the world to climate
change, sea level rise and salt water intrusion. Salinity stress adversely affects the
growth and yield of maize plant. Therefore, we need to understand the
mechanisms of plant adaptation to salinity and to develop salt tolerant maize
genotypes under changing climate scenarios. This study was undertaken to
screen 33 maize genotypes for salt tolerance based on morphological,
physiological and biochemical attributes. To fulfill this purpose, four experiments
were conducted in the Department of Crop Botany, Bangladesh Agricultural
University, Mymensingh and Agricultural Research Station, BARI, Benarpota,
Satkhira. Firstly, a germination test was done with 33 maize genotypes under
three salinity levels; 0 dSm-1 (control), 8 dSm-1 and 16 dSm-1. Based on the
performances of germination percentage, stress tolerance indices and plumule
and radicle length, 18 genotypes were selected for seedling growth study in
hydroponic condition under two salinity levels (0 and 12 dSm-1). Morphological,
physiological and biochemical data such as root and shoot fresh and dry weight,
relative greenness (SPAD), photosynthesis rate (PN) and total Na+ and K* content
were measured in control and stressed plants. Eight genotypes (six salt tolerant
and two salt susceptible) were screened and selected for pot experiment in
respect to relative values of the measured traits in hydroponic condition. The
plants were grown in pot under two salinity levels (0 and 12 dSm-1). Data
regarding root, stem and leaf fresh and dry weight, total Na+ and K+ content and
proline contents were recorded. All these parameters were significantly affected
by salinity stress and a significant variation among the genotypes was observed.
Finally, a field experiment was set to investigate the growth and yield
performance of selected eight genotypes in a coastal saline area in Bangladesh.
The study showed that the performance of maize genotypes in relation to
growth, Na+ and K+ content was more or less similar in both field and pot
conditions. In conclusion, considering the growth, ion uptake and other
measured attributes, Star Beej 7Star, Bharati 981 and Unigreen UB100 were
considered as salt-tolerant whereas Seed Tech Bisco Prince and Dekalb Elit were
observed to be the most salt-sensitive maize genotypes. The salt-tolerant maize
found in this study could be used for the cultivation in salinity genotypes
affected areas of Bangladesh and further breeding program for the development
of salt tolerant maize genotypes.