SCREENING OF DIFFERENT COTTON (Gossypium hirsutum L.) GENOTYPES FOR SALT TOLERANCE DURING GERMINATION

Abstract

The experiment was conducted at the laboratory of Genetics and Plant Breeding Department of Hajee Mohammad Danesh Science and Technology University Dinajpur during October to November, 2015 to investigate the effects of different levels of NaCl solutions on germination of thirteen genotypes of cotton. The genotypes of cotton were CB-9, CB-10, CB12, CB-13 (four released genotype), SR-15, Ra-3, Ra-5, Ra-9, JA-08/A, JA-08/B, JA-11/4, BC-0168 and Ra-16 (nine advanced line) and five levels of NaCl salt solutions were control (normal water), 4 dSm -1 , 8 dSm -1 , 12 dSm -1 and 16 dSm -1 . The experiment was laid out in completely randomized design (CRD) with three replications. Data on days required to 1st germination, days to 50% germination, germination percentage, shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, number of lateral roots, vigor index and proline accumulation by cotton seedlings were recorded at 10th days after sowing (DAS) of seeds in plastic pots. Results on the effects of the genotypes and different salinity level on germination of seed revealed that there was significant variation among thirteen genotypes of cotton at 10 th days after sowing the seeds. Within the genotypes SR-15 and BC-0168 were showed highest value in germination parameters than other genotypes in all the treatment. Significant variation was observed in germination due to effect of different salinity level. In all the treatments, BC-0168 genotype germinated earlier (4-6 DAS) and showed highest germination percentage (96.67% - 66.67%) than other genotypes while CB-13 showed lowest value in most of the cases. Seedling parameters like shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight and number of lateral roots also showed significant variation among the studied genotypes. The highest number of lateral root (19.93) was found in BC-0168 followed by Ra-3 (19.80) and highest dry weight of shoot (0.5707 g) was also found in Ra-5. The maximum dry weight of root (0.166 g) was obtained from Ra-3 while JA-11/4 showed highest shoot fresh weight (2.867 g) and highest root fresh weight (0.81 g) was obtained from control treatment in Ra-5. The seedling vigor was maximum (2491) in Ra-16 under control treatment which is statistically similar with BC-0168 and minimum (1425.7) from CB-10. But at higher salinity level (16 dSm -1 ) BC-0168 showed maximum seedling vigor (819) while CB-13 (336.7) and CB-10 produced lowest seedling vigor. Among the salt treated genotype, BC-0168 accumulated more proline than other genotype under control to moderate salinity (0.1627 - 0.21 mg proline/g FW) while Ra-3 accumulated lowest value which is similar with SR-15 and CB-12. But at higher salinity both BC-0168 and JA-08/B accumulated highest value (0.2267-0.2520 mg proline/g FW) than all other genotype since SR-15, CB-9, CB-10 and CB-12 accumulated lowest proline content. Among the thirteen genotypes of cotton, BC0168, Ra-16 and Ra-5 were comparatively more tolerant to NaCl saline action compared to others where as CB-13 and SR-15 more sensitive to saline action.