Bangladesh Agron. J. 2016, 19(2): 1-10 VARIATIONS OF GROWTH PARAMETERS IN SOME AROMATIC RICE VERITIES UNDER SALT STRESS Md. Habibur Rahman1, Md. Abu Naim1, Md. Abdul Matin1, Taufika Islam Anee1, Md. Amzad Hossain2 and Mirza Hasanuzzaman1* 1Department of Agronomy, Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh 2Subtropical Field Science Center, University of the Ryukyus, 1 Senbaru, Nishihara City, Okinawa 903-0213, Japan *Corresponding Author: mhzsauag@yahoo.com Key words: Abiotic stress, Growth, Irrigated rice, NaCl, Salinity Abstract A pot experiment with six aman rice varieties viz. BRRI dhan34, BRRI dhan38, Binadhan-9, Binadhan-13, Kalijira and Rajbhogh was conducted at the experimental shed of the Department of Agronomy, Sher-e Bangla Agricultural University, Dhaka during the period of June- December, 2014 to investigate the effect of salinity on the growth, physiology and yield of some aromatic rice under different salt stress conditions. The experiment was carried out with five salt stress treatments viz. control (without salt), S25 (25 mM NaCl), S50 (50 mM NaCl), S75 (75 mM NaCl) and S100 (100 mM NaCl). Salt stress significantly reduced the plant height, tiller hill-1 and leaves hill-1 of these varieties at all growth duration. Among the varieties Binadhan-9 and BRRI dhan38 performed better under saline condition. On the other hand, local variety Kalijira did not perform well under saline condition. Introduction Soil salinity is a widespread environmental problem that has been found to affect over 77 million hectares or about 5% of the arable land worldwide (Wang et al., 2001; Athar and Ashraf, 2009). Due to climate change this salt affected areas are increasing day by day and assumed to affect 50% of cultivable land by the midth of 21st century (Mahajan and Tuteja, 2005). Salinity is a major threat to crop productivity in the southern and south-western parts of Bangladesh, where it is developed due to frequent flood by sea water of the Bay of Bengal. In Bangladesh out of 2.85 million hectares of the coastal and off-shore areas about 0.833 million hectares are arable lands, which constitute about 52.8 percent of the net cultivable area in 13 districts (Karim et al., 1990). Introduction of irrigation with saline waters in those areas is another possible reason of the increasing content of salinity. Salinity has adverse effects on plant growth and productivity. According to Bray et al. (2000) salt stress can account for up to 50% yield reduction of the major crops. The nature of damage by salt stress is very complex as it causes both osmotic stress and ionic toxicity (Hasanuzzaman et al., 2013). Plants can respond and adapt to salt stress by altering their cellular metabolism and invoking various defense mechanisms (Ghosh et al., 2011). The survival of plants under this stress condition depends on their abilities to perceive the stimulus, generate and transmit a signal, and initiate various physiological and biochemical changes (Tanou et al., 2009; El-Shabrawi et al., 2010). Irrigated rice is well suited to control and even mitigate soil salinity (Wopereis et al., 1998). But rice is a salt-sensitive crop and yield losses due to salinity can be substantial (Asch et al., 1997). 2 Rahman et al. Aromatic rice varieties have gained significant market shares in the global rice trade. As a result, efforts are being undertaken in many countries to increase the production of this type of rice. There are evidences showing that the aromatic quality of these rice varieties varies depending upon the areas and locality of the rice cultivation (Bradbury et al. 2008; Hossain et al. 2008; Nagarajan et al. 2010). Considering the above mentioned perspectives, the present study was undertaken to investigate the effect of salinity on the growth performance of some aromatic rice varieties in relation to HYV ones. Materials and Methods The experiment was conducted at the experimental shed of the Department of Agronomy, Sher-e-Bangla Agricultural University, Dhaka (23.770155° N, 90.374358° E) during the period June-December, 2014. The soil of the experimental area belongs to the Modhupur tract (AEZ No. 28). It was a medium high land with non-calcarious dark grey soil. The pH value of the soil was 5.6. Six aromatic rice varieties including four HYVs and two lacal varieties were used in this experiment. The HYVs are: BRRI dhan34, BRRI dhan38, Binadhan-9 and Binadhan-13; and the local variities are: Kalijira and Rajbhogh. The experiment was laid out in a Factorial Randomized Completely Block Design (RCBD) with three replications. There were 90 pots all together replication with the given factors. The salinity treatments were applied on 30 days after transplanting (DAT), 45 DAT, 60 DAT and 75 DAT. There were five salinity levels including control. Salinity was induced by adding respected amount commercial NaCl salt to the soil/pot as water dissolved solution. The salinity levels were C (fresh water), S25 (25 mM NaCl), S50 (50 mM NaCl), S75 (75 mM NaCl) and S100 (100 mM NaCl). Seeds were soaked for 48 h and then washed thoroughly in fresh water and incubated for sprouting. The sprouted seeds were sown in the wet seedbed. The experimental pots were fertilized with 250, 110, 140, and 50 kg ha-1 N, P2O5, K2O, and S applied in the form of urea, triple super phosphate, murate of potash, and gypsum respectively. One-third of urea and the whole amount of other fertilizers were incorporated with soil at final pot preparation before sowing. Rest of the nitrogen were applied in two equal splits one at 30 DAT and second at 45 DAT. Thirty-day-old seedlings were uprooted carefully from the seedbed and transplanted in the respective pots at the rate of single seedling hill-1. All intercultural operations were done as per recommendation. The data obtained for different parameters was statistically analyzed following computer based software XLSTAT 2014 (AddinSoft, 2016) and mean separation was done by least significant difference test (LSD) at 5% level of significance. Results and Discussion Plant height Plant height of different varieties was measured at different growing period (Table 1). The highest plant height was found in BRRI dhan38 at all growth duration except 90 DAT (97.98 cm at 30 DAT, 108.41 cm at 45 DAT, 110.51 cm at 60 DAT and 113.71 cm). However, highest plant height also observed in BRRI dhan34 at 75 DAT (112.33 cm) and at 90 DAT (119.05 cm); in Rajbhog at 30 DAT (97.98 cm). The plant height of BRRI dhan34 at 90 DAT and Rajbhog at 60, 75, and 90 DAT were statistically similar. This result was supported by Hossain and Sikdar (2009). Plant height differed significantly at different salinity treatments (Table 1). It was significantly greater at control than the other salinity levels. At 30 DAT, plant height 3 Variations of Growth Parameters in Some Aromatic Rice Verities Under Salt Stress was the maximum at control (93.10 cm) which was statistically similar to that of 25 mM salinity (90.53 cm). The mimimum plant height (82.42 cm) was recorded at 100 mM salinity which was statistically similar to that of 75 mM (86.16 cm) salinity. The decreasing trends of the plant height were found with increasing salinity at 45 D and 90 DAT. Gradual decrease in plant height might be due to the nutrient unavailability caused by increased salinity or the inhibition of cell division or cell enlargement. Salinity has direct effect in plant height. Choi et al. (2003) observed that the plant height decreased in the 0.5% saline water in the soil. Table 1. Effect of variety and salinity level on plant height of rice at different days after transplanting Variety Plant Height (cm) 30 DAT 45 DAT 60 DAT 75 DAT 90 DAT BRRI dhan34 87.59bc 98.95bc 104.82bc 112.33a 119.05a BRRI dhan38 97.98a 108.41a 110.51a 113.71a 118.31ab Binadhan-9 88.79bc 98.77bc 104.19bc 111.00a 113.91bc Binadhan-13 85.56 c 95.90 c 100.32c 105.69b 110.27c Kalijira 77.84d 87.20d 92.55d 99.41c 103.16 d Rajbhogh 97.98a 101.88 b 108.77ab 109.34ab 117.85ab LSD (0.05) 4.18 4.90 5.11 5.06 5.01 Salinity level C 93.10a 103.11a 108.85a 114.49a 119.38a S25 90.53ab 100.94a 105.6a 111.24a 116.28ab S50 89.02bc 98.73ab 104.27ab 110.35a 113.97bc S75 86.16cd 96.41bc 100.93bc 103.66 b 111.46cd S100 82.42d 93.41c 97.96c 103.16b 107.70d LSD (0.05) 3.82 4.48 4.68 4.63 4.58 CV (%) 6.49 6.81 6.77 6.39 6.04 Values in a column with different letters are significantly different at p ≤ 0.05 applying LSD. The combined effect of salinity and varieties on plant height was significant at p≤0.05 (Table 2). Plant height generally decreased w ith the increasing level of salinity. In interaction effects plant height was highest at control plants of BRRI dhan38 and lowest at 100 mM salinity levels of Kalijira variety. Similar results were recorded by Khandakar and Alim (2004). Chen et al. (1989) reported that plant height seriously decreased by salinity. Tillers hill-1 There was a significant variation found in number of tillers hill-1 due to varietal variation (Table 3). The highest number of tillers hill-1 was found at 30 DAT (4.76), at 75 DAT (25.27) and at harvest (20.51) in case of Binadhan-9; at 45 DAT (10.13) and at 60 DAT (16.03) in case of BRRI dhan38 and at 45 DAT (10.03) in case of Binadhan-13. However, the lowest number of tillers hill-1 observed at 30 DAT (3.61) in BRRI dhan34; at 45 DAT (7.14), 60 DAT (12.59), 90 DAT (13.47) and harvest (12.02) in Kalijira; at 75 DAT (18.66) in Binadhan-13. 4 Rahman et al. Table 2. The combined effects of salinty and Aman rice varieties on plant height at different days after trasplanting Variety Salinity treatment Plant height (cm) 30 DAT 45 DAT 60 DAT 75 DAT 90 DAT BRRI dhan34 C 93.07a-g 103.07abc 109.83a-f 114.43a-e 122.73abc S25 89.90c-h 100.63bc 106.50a-f 112.67a-f 122.07abc S50 89.13 c-h 99.13bcd 106.13a-f 112.43a-f 119.73a-e S75 83.80g-k 96.40cde 101.87d-i 111.60a-f 118.30a-e S100 82.07 h-l 95.53c-f 99.77 f-j 110.50a-g 112.40c-i BRRI dhan38 C 101.90a 112.00a 116.73a 118.10a 124.50a S25 101.00ab 112.30a 113.70ab 118.10a 120.60a-d S50 97.60abc 107.63ab 111.27a-e 116.53abc 117.30a-f S75 96.63a-d 105.77abc 106.53a-f 109.50a-h 115.30a-g S100 92.80a-g 104.33abc 104.30 b-g 106.23b-i 113.83a-h Binadhan-9 C 91.80b-g 101.90abc 107.03a-f 114.73a-d 118.40a-e S25 89.17c-h 99.37bcd 104.37b-g 114.93a-d 118.20a-e S50 88.83c-h 98.40bcd 104.60 b-g 114.34a-e 116.53a-f S75 88.43c-h 98.47bcd 103.90b-h 106.53b-i 109.50d-j S100 85.73f-j 95.73c-f 101.07d-i 104.47d-i 106.90f-k Binadhan- 13 C 90.43c-h 100.40bc 106.07a-f 116.97ab 116.03a-g S25 89.67c-h 99.63bc 103.70c-h 103.20e-i 113.83a-h S50 86.8e-i 97.33b-e 100.40e-j 110.23a-g 110.00d-j S75 85.47f-j 95.33c-g 98.90f-k 98.53hij 108.97e-j S100 75.43kl 86.80e-h 92.53h-k 99.53g-j 102.53ijk Kalijira C 85.70f-j 95.43c-g 100.83e-j 108.50a-h 105.27g-k S25 78.10 i-l 88.50d-h 93.17h-k 105.23c-i 102.97h-k S50 77.30j-l 85.03fgh 91.80ijk 95.87ij 99.60jk S75 74.77kl 84.53gh 89.4jk 90.97j 102.97h-k S100 73.27l 82.50 h 87.50k 96.47ij 97.47 k Rajbhogh C 95.73a-e 105.83abc 112.60abc 114.23a-e 124.13ab S25 95.37a-e 105.23abc 112.30a-d 113.20a-e 117.70a-f S50 94.40a-f 104.83abc 111.40 a-e 112.67a-f 117.27 a-f S75 87.87d-h 97.93bcd 104.97b-f 104.83 d-i 117.07a-f S100 85.23f-j 95.5c-f 102.57b-i 101.77f-j 113.07b-i LSD (0.05) 9.36 10.96 11.44 11.33 11.22 CV (%) 6.49 6.81 6.77 6.39 6.04 Values in a column with different letters are significantly different at p ≤ 0.05 applying LSD. 5 Variations of Growth Parameters in Some Aromatic Rice Verities Under Salt Stress Table 3. Effect of variety and salinity level on number of tillers hill-1 of rice at different days after transplanting Variety Number of tillers hill-1 30 DAT 45 DAT 60 DAT 75 DAT 90 DAT At Harvest BRRI dhan34 3.61e 7.52c 14.22c 20.02d 16.28d 15.36d BRRI dhan38 4.76c 10.13a 16.03a 21.78c 17.56c 17.38c Binadhan-9 5.52a 9.51b 15.11b 25.27a 20.69a 20.51a Binadhan-13 5.14b 10.03a 13.68c 18.66e 14.91e 14.07e Kalijira 3.98d 7.14d 12.59d 23.54b 13.47f 12.02f Rajbhogh 4.70c 9.57b 13.96c 20.02d 18.37b 19.31b LSD (0.05) 0.20 0.41 0.65 0.77 0.73 0.67 Salinity level C 7.34a 14.52a 20.21a 26.64a 21.45a 19.54a S25 6.32b 11.98b 18.37b 24.76b 19.53b 18.29b S50 4.61c 8.96c 13.98c 20.58c 17.03c 16.41c S75 2.98d 5.66d 10.50d 17.52d 14.21d 14.78d S100 1.83e 3.79e 8.27e 14.60e 12.17e 13.20e LSD (0.05) 0.19 0.38 0.59 0.71 0.66 0.61 CV (%) 6.21 6.38 6.25 5.11 5.92 5.62 Values in a column with different letters are significantly different at p ≤ 0.05 applying LSD. Application of salt decreased the number of tillers hill-1 of rice varieties (Table 3). It was significantly greater at the control than in other salinity levels. The highest number of tillers hill-1 was recorded in control at all growing period (7.34 at 30 DAT, 14.52 at 45 DAT, 20.21 at 60 DAT, 26.64 at 75 DAT, 21.45 at 90 DAT and 19.54 at harvest. With the increasing salinity levels the number of tillers hill-1 drastically reduced. So, the lowest number of tillers hill-1 found in 100 mM salinity level at all growth periods. It was observed that number of productive tillers hill-1 decreased with increase in salinity levels (Heenan and Lewin, 1998 and Hasamuzzaman et al., 2009). The interaction effect of salinity levels and cultivars in relation to the number of tillers hill-1 was found significant (p ≤ 0.05) (Table 4) at all growing periods. The highest number of tillers hill-1 was obtained from Binadhan-9 at control condition with the increase of growing period (8.33 at 30 DAT, 17.30 at 45 DAT, 22.43 at 60 DAT, 31.55 at 75 DAT, 25.17 at 90 DAT and 23.02 at harvest. But sometimes BRRI dhan38 at 30 DAT and Binadhan-13 at 30 DAT obtained highest tillers hill-1. The lowest number of tillers hill-1 was obtained from Kalijira at 100 mM salt treatment with the increase of growing period (1.17 at 30 DAT, 3.11 at 45 DAT, 7.51 at 60 DAT, 10.43 at 75 DAT, 8.45 at 90 DAT and 8.29 at harvest). Islam et al. (2007) also reported that increasing salinity levels negatively affects the number of tillers hill-1. 6 Rahman et al. Table 4. The combined effects of salinty and Aman rice varieties on no. of tillers hill- 1 at different days after trasplanting Variety Salinity treatment Number of tillers hill-1 30 DAT 45 DAT 60 DAT 75 DAT 90 DAT At Harvest BRRI dhan34 C 6.16c 13.30c 20.63b 25.85de 20.52de 18.97cd S25 5.28d 10.37efg 18.64cd 23.13f 18.98ef 16.33gh S50 3.15f 6.57j 13.45fg 19.8hi 17.183ghi 15.22hi S75 2.30g 4.04lm 11.40hi 17.50 j 13.43lm 13.43jkl S100 1.16h 3.25lmn 7.00k 13.70k 11.30no 12.88jkl BRRI dhan38 C 8.00a 14.70b 20.54b 27.92bc 22.40bc 20.32bc S25 7.08b 13.40c 19.50bc 25.63e 19.66ef 18.46def S50 5.11d 10.39ef 17.26de 21.80fg 18.46fg 17.52defg S75 2.26g 7.02j 12.28gh 18.61ij 14.56kl 16.22gh S100 1.33h 5.16k 10.59ij 14.95k 12.73mn 14.37ij Binadhan-9 C 8.33a 17.30a 22.43a 31.55a 25.517a 23.02a S25 7.01b 11.54d 19.72bc 29.32b 23.63b 22.53a S50 5.18d 9.45ghi 13.57fg 25.51e 19.51ef 20.85b S75 4.05e 5.18k 10.37ij 22.53f 18.22f-i 18.88cde S100 3.04f 4.08l 9.46j 17.44j 16.60ij 17.29fg Binadhan- 13 C 8.29a 14.69b 20.23b 23.37f 18.55fg 17.21fg S25 7.17b 13.39c 17.52de 22.40f 16.82hij 16.66gh S50 5.12d 9.44hi 13.55fg 19.47hi 15.41jk 13.76ijk S75 3.10f 8.54i 9.56j 14.72k 13.31lm 12.37kl S100 2.05g 4.08l 7.53k 13.35k 10.50o 10.34m Kalijira C 6.13c 11.58d 17.71de 22.40f 18.67g 15.22hi S25 5.27d 9.57fgh 16.53e 20.54gh 16.65ij 14.13ij S50 5.10d 7.45j 11.47hi 13.49k 13.22lm 12.07l S75 2.28g 4.03lm 9.72j 11.40l 10.36o 10.33m S100 1.17h 3.11mn 7.51k 10.43l 8.45p 8.29n Rajbhogh C 7.17b 15.40b 19.73bc 28.73bc 23.08bc 22.49a S25 6.21c 13.67c 18.28cd 27.55cd 21.46cd 21.60ab S50 4.00e 10.50e 14.60f 23.33f 18.43fgh 19.01cd S75 3.90e 5.18k 9.66j 20.40gh 15.41jk 17.45efg S100 2.25g 3.06n 7.54k 17.72j 13.48lm 16.02gh LSD (0.05) 0.46 0.93 1.45 1.73 1.63 1.51 CV (%) 6.21 6.38 6.25 5.11 5.92 5.62 Values in a column with different letters are significantly different at p ≤ 0.05 applying LSD Number of Leaves hill-1 Number of leaves of different rice varieties differed significantly due to salinity (Table 5). BRRI dhan34 produced the highest number of leaves at all growth duration except 7 Variations of Growth Parameters in Some Aromatic Rice Verities Under Salt Stress 30 DAT (155.03 at 45 DAT, 163.62 at 60 DAT, 145.18 at 75 DAT and 122.65 at 90 DAT). However, the lowest number of leaves was recorded in Binadhan-9 at 30 DAT (77.09), at 45 DAT (91.83) and in Binadhan-13 at 75 DAT (94.57), at 90 DAT (94.32). Table 5. Effect of variety and salinity level on number of leaves hill-1 of rice at different days after transplanting Variety Number of Leaves hill-1 30 DAT 45 DAT 60 DAT 75 DAT 90 DAT BRRI dhan34 111.84b 155.03a 163.62a 145.18a 143.08a BRRI dhan38 116.95a 133.65b 147.66b 122.47c 122.65b Binadhan-9 77.09 e 91.83e 118.63d 107.97d 116.92b Binadhan-13 85.15d 116.05d 126.76c 94.57e 94.32c Kalijira 92.35c 122.55c 113.62d 94.46e 99.31c Rajbhogh 92.15c 112.97d 153.95b 136.30b 137.46a LSD (0.05) 4.88 6.04 7.04 6.19 6.22 Salinity level C 114.64a 156.40a 183.22a 159.84a 156.92a S25 105.30b 136.75b 158.83b 135.33b 135.80b S50 95.24 c 120.29c 138.96c 116.96c 118.26c S75 86.86d 89.17d 114.37d 92.68d 100.67d S100 77.56 e 107.46e 91.47e 79.33e 83.14e LSD (0.05) 4.45 5.52 6.43 5.65 5.68 CV (%) 6.97 6.78 7.02 7.26 7.16 Values in a column with different letters are significantly different at p ≤ 0.05 applying LSD. Different salinity treatments affected the number of leaves hill-1 significantly throughout the growing period. Salinity treatment reduced the number of leaves hill-1 compared to control (Table 5). The highest number of leaves recorded at control from the beginning to end (114.64 at 30 DAT, 156.40 at 45 DAT, 183.22 at 60 DAT, 159.84 at 75 DAT and 156.92 at 90 DAT). With the increase of salinity level the number of leaves hill-1 reduced. The lowest number of leaves hill-1 observed in 100 mM saline condition at all growing period. This result showed that number of leaves hill-1 decreased gradually with the increasing salinity levels. Similar results were reported by Dabnath (2003). Sharp decreases in number of leaves hill-1 was observed in response to salt stress, compared to the control at 30, 45, 60, 75 and 90 DAT for six aman rice varieties (Table 6). The highest number of leaves hill-1 was recorded in BRRI dhan34 at all DAT(127.81 at 30 DAT, 194.74 at 45 DAT, 205.01 at 60 DAT, 183.06 at 75 DAT and 184.08 at 90 DAT) during control condition. But after the application of salt at different concentrations, the number of leaves hill-1 was reduced. Kalijira showed lowest number of leaves hill-1 at 100 mM saline condition (70.85 at 45 DAT, 68.57 at 60 DAT, 55.02 at 75 DAT and 62.28 at 90 DAT) which were similar in case of Binadhan-13 at 100 mM saline codition during 45 DAT and in case of Binadhan-9 at 100mM saline during 75 DAT. This results are supported by Alamgir and Ali (2006). 8 Rahman et al. Table 6. The combined effects of salinty and Aman rice varieties on number of leaves hill-1 at different days after trasplanting Variety Salinity treatment Number of leaves hill-1 30 DAT 45 DAT 60 DAT 75 DAT 90 DAT BRRI dhan34 C 127.81a 194.74a 205.01a 183.06a 184.08a S25 125.59a 147.57cd 172.60bc 161.33bc 163.94b S50 108.12cd 147.23cd 166.36bc 148.25cd 137.36de S75 104.72c-f 144.06cd 163.71cd 121.34e 130.63efg S100 92.95g-k 141.54de 110.41jk 111.94e 99.41j BRRI dhan38 C 131.79a 175.87b 178.91bc 165.23b 156.25bc S25 127.44a 140.44de 178.00bc 145.44d 153.54bc S50 121.58ab 128.66ef 173.28bc 142.17d 147.13cd S75 114.21bc 122.83ef 113.68ijk 86.90fg 84.24k S100 89.72h-l 100.44i-l 94.43lm 72.61h 72.09klm Binadhan-9 C 86.59i-m 128.45ef 164.19cd 162.42b 161.72b S25 83.74j-n 108.15hij 145.84ef 117.16e 122.36fgh S50 83.32k-n 95.92jkl 124.43g-j 109.52e 117.68f-i S75 66.15pq 64.25m 87.89mn 78.92gh 113.73lm S100 65.64pq 62.36m 70.79o 71.80h 69.10ef Binadhan- 13 C 122.87ab 145.69cd 181.34b 142.39d 131.23ij S25 94.27f-j 140.18de 150.44de 115.55e 106.08kl S50 78.23mno 115.75fgh 119.65h-k 87.46fg 79.50k S75 67.67opq 109.53ghi 104.40kl 78.93gh 79.71l S100 62.72q 69.10m 77.95no 48.50i 75.11klm Kalijira C 105.72cde 157.06c 170.20bc 139.30d 146.71cd S25 99.96defgh 145.42cd 134.74e-h 112.86e 117.07ghi S50 96.20efghi 128.21ef 111.17ijk 93.07f 99.28j S75 85.03j-n 111.23ghi 83.43mno 72.07h 71.20kl S100 74.83nop 70.85m 68.57o 55.02i 62.28m Rajbhogh C 113.05bc 136.57de 199.69a 166.61b 161.52m S25 100.83d-g 138.71de 171.36bc 159.62bc 151.81b S50 83.97j-n 105.97h-k 138.89efg 121.27e 128.63bc S75 83.38j-n 92.88l 133.14fgh 117.92e 124.51efg S100 79.52lmn 90.72k 126.67ghi 116.09e 120.83e-h LSD (0.05) 10.92 13.53 15.76 13.86 13.93 CV (%) 6.97 6.78 7.02 7.26 7.16 Values in a column with different letters are significantly different at p ≤ 0.05 applying LSD Conclusion Despite rice var. 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