GERMINATION AND GROWTH PERFORMANCE OF THREE RICE VARIETIES UNDER SALINITY STRESS

Abstract

Salinity is major constrain to rice production in southern part of Bangladesh. Rice yield reduction is caused by salinity due to its adverse effect on many important physiological processes. The present study was therefore designed to select salt tolerant rice varieties. The research was conducted in three rice varieties (Nonabokra, Botessor and BRRI dhan28) for the coastal areas of Bangladesh. Germination of three rice varieties were studied under three salinity levels in the laboratory of HSTU dinajpur, the experiment was conducted during the period of July to December 2017. The results showed that Nonabokra were tolerant and Botessor was moderately tolerant based on germination test experiment. However, germination test, shoot and root length of Nonabokra, Botessor and BRRI dhan28 seeds under different salinity levels were also performed. The highest germination (90%, 86.67 % and 100%) was found in Nonabokra, Botessor and BRRI dhan28, respectively with the treatments of 3 dSm-1, 6 dS m-1, and 9 dS m-1. The highest shoot and root weight of seedlings were found in 3 dS m-1. It was observed that all salinity effluents could also delay germination and growth of crops such as BRRI dhan28. However, overall view suggests that the salinity was not suitable for germination of the rice varieties except Nonabokra. Subsequent studies on growth, biochemical constituents, and mineral composition of three rice varieties under different salinity levels in the pots were conducted experiment and the result revealed that the growth of rice plants were arrested instantly at 9 dS m-1 . The highest proline accumulation was found in Nonabokra while the lowest accumulation was in BRRI dhan28. The highest proline increment (3.19) was in Nonabokra, while the lowest (0.55) was in BRRI dhan28. The total chlorophyll content were observed from 14.54 to 0.55. The carotene content ranger from 4.30 to 0.66. The sodium concentration was ranger from 459 to 71.67. The potassium concentration of rice varieties was founded as from1180 to 248.3. The calcium concentration was from 1077 to 140.3. The magnesium concentration were from 1158 to 165. The sulfur concentration were from 801 to 133.7. The phosphors concentration were from 12.86 to 1.95. The zinc concentration were from 3.66 to 0.35. The overall result revealed that among the tested rice varieties one variety were selected of which Nonabokra appeared as salt tolerant, while Botessor was moderately tolerant, and BRRI dhan28 was more susceptible to salinity. So it can be suggested that Nonabokra is more appropriate variety to cultivate in the coastal area of Bangladesh.