Response of newly released cotton varieties to plant spacing and density, under rain-fed conditions, at Damazin Osama M. A. Elhassan Abstract: Field experiments were conducted during 26-21 cropping seasons, at Damazin Research Farm, under rain-fed conditions, to study the effects of different plant densities on growth, yield and fiber quality of four new released cotton varieties. Treatments tested were factorial combinations of four cotton varieties (Hamid, Burhan, Khalifa and Wagar) and four intra-row spacing (15, 2, 3 and 45cm). Treatments were laid out in a randomized complete block design, with four replications. Data on some growth attributes, yield, yield components and fiber characteristics were collected. In general, wider spacing enhanced early flowering and produced taller plants compared to the closer ones. Number of bolls/m² was increased with the increase of plant density, while boll weight (g) was increased with the decrease of plant density. The 45cm intra-row spacing showed higher lint (%) than others. Varieties Hamid and Burhan produced larger boll weight and higher seed index, while Khalifa and Wagar showed higher lint index and lint%. In 27, 28 and combined seasons data the differences in plant densities were not significant. In 26 and 29, yield was increased due to the narrow intra-row spacing. The two varieties Burhan and Khalifa produced significantly higher yields than the two others. Introduction: Cotton, (Gossypium sp) is one of the major cash crops, in many tropical and sub- tropical countries of the world. In the Sudan, it is one of the most important cash crops. Three types of cotton viz. the long staple Egyptian cotton (Gossypium barbadanse), the medium staple American upland cotton (Gossypium hirsutum) and the short staple cotton (Gossypium hirsutum) are grown in Sudan. The short and medium staples cotton are grown as rain-fed crop in the central clay plains of Sudan and in the southern States. Newly released cotton varieties (Hamid, Burhan, Khalifa and Wagar) were recommended for production, in the rain-fed sector, because of their high yields, early maturity and high resistance to bacterial blight (Mustafa et al., 24 and 26). High levels of production require favorable combinations of climate, soil and cultural practices. Cotton requires from four to five months of warm temperature (about 32º c) during the growing season. Although cotton is grown on a wide range of annual precipitation, the distribution of rainfall is an important controlling factor in its production. The crop can be produced on a wide variety of soils. The attainment of the yield potential of this crop is often limited by poor cultural practices (sowing date, plant density, mineral nutrition's...etc). Plant spacing (plant population) is a factor that influences cotton production; and it has been studied for many years under irrigated and rain-fed areas. Studies indicate that the cotton yield increases due to the narrow inter-row spacing (Fadda, 1961; Burhan, 1967; Babiker, 1987 and 1988). Taha (1962, 1963) reported that, yield was increased with the increase of plant population from 225 to 525 plants/fed. Some reports showed no significant difference between 3, 4, 5 and 6 cm intra-row spacing (Babiker, 1986; Lazim, 1986, 1987, 1988 and 199). Babiker (24) showed that the optimum density (at Rahad area) was achieved by planting 3plants/hill spaced at 8 x 3 cm (525 plants/fed). Elhassan and Abdelatif (25) 1
concluded that, yield was increased with the narrow inter-row spacing, while the effect of intrarow was not significant. The objectives of this work were to test the response of four new released cotton varieties to different plant densities, and determine the optimum plant population, under rainfed conditions, at Damazin. Materials and methods: Field experiments were conducted during 26-21 growing seasons in the Agricultural Research Farm, at Damazin (long. 34º 21 E, lat. 11º 47 N; 492m above sea level). The area is a semi- humid environment. Treatments were factorial combinations of four cotton varieties (Hamid, Burhan, Khalifa and Wagar) and four levels of intra-row spacing (15, 2, 3 and 45cm). Variety Wagar was tested for two seasons. These treatments were carried out in a randomized complete block design replicated four times. Plot size was 3.2m x 7.2m. Cultural practices The land was ploughed with the wide-level disc, each season. Sowing was carried-out during the first three weeks of July. Sowing was done by hand in rows, 8cm apart. Seedlings were thinned to two plants/hole three weeks after sowing. Nitrogen fertilizer (in the form of urea 46% N) at the rate of 18kg N/fed was band applied one week after thinning. The experiment was hand weeded three times during the growing season. Insect pests were controlled with regular pesticides when required. Data collection Data pertaining to growth attributes and development were recorded on plant height (cm), number of sympodial branches and number of nodes to first fruiting branch, from five plants, selected at random in each plot. Days to first flowering and first boll opening were recorded. Measurement of yield components and yield of cotton Number of bolls/plant was recorded from five plants sample, selected randomly from each plot prior to picking. Boll attributes such as boll size, lint index, seed index and lint percentage (G.O.T. %) were determined from 1 bolls samples taken at random from each plot prior to harvesting. Seed cotton yield were taken from the net area of 8.3m² (2 rows x.8m x 5.2m) in each plot. The harvested cotton was weighed to obtain seed cotton and lint yield (kg/fed). Cotton fiber quality test Measurements of fiber length (2.5% span length mm), fiber fineness (Mic.), fiber strength (HVI) and stickiness (SCT) were made from a portion of the lint taken from each sample to determine boll attributes. These fiber properties measurements were made by the Fiber Spinning and Stickiness Testing Lab., ARC, Wad Medani, Sudan. Count of insect pests was carried out in two seasons, according to ARC procedure. Data collected were subjected to statistical analysis using Mstat for each season separately and SAS for combined seasons data analysis. Levels of significance for.5,.1 and.1 probabilities for main factors and interaction responses were calculated. Significantly 2
different means were separated by the Duncan s Multiple Range Test (DMRT) for significance at the.5 level of probability. Results and discussion: Growing conditions Average monthly maximum and minimum temperatures, relative humidity and rainfall during the growing periods are presented on Table 1. Most of the rainfall was received in June, July, August and September with little amount in October; the total rainfall was higher than 8mm in 27 and 28 seasons, while in the other seasons was lower than 7mm. In season 26, temperature was higher in May with average of about 3.7 C and lower in December with average of about 24.8C. Relative humidity was high during the rainy seasons (6-8%) and dropped to about 33 in December. Neither temperatures nor humidity had a negative impact on growth and development. All were within the normal range for the cotton crop. Plant density Table 2 shows the actual plant density as affected by variety and intra-row spacing during 26-21 seasons. Earliness parameters Table 3 showed the main effects of variety and intra-row spacing on days to first flowering, days to first boll opening and number of nodes to first fruiting branch (averaged over five seasons), which are indications of the earliness. In general, the wider the spacing the lower the sympodia and the shorter it took to give the first flower. On the other hand, variety Hamid showed significantly longer period to first flower (59days after emergence) and first boll opening (15 days).variety Wagar showed shorter period, while, the difference between Burhan and Khalifa was not significant. The Variety x intra-row spacing interaction effect was not significant. Plant height and number of sympodia/m² On average, the wider intra-row spacing (3-45cm) showed significantly (p.1) taller plants compared to closer one (15-2cm), table 4. Number of sympodia/m² was increased significantly with the increase of plant density (closer intra-row spacing), irrespective of variety (Table 4). Variety Hamid produced taller plants than other varieties (average over five seasons). Differences in number of sympodia due to variety were not significant (Table 4). Only the interaction effect was significant for plant height in 29, and variety Hamid and Burhan were not responsive to plant spacing (Table 8a). Yield and yield components Main effects of variety and intra-row spacing on yield components (number of bolls/m², boll weight- g, seed index- g, lint index- g and G.O.T. %) are presented on Table 5 (average over five seasons). Number of bolls/m² was increased significantly with the increase of plant density. While, boll weight (g) was increased with the decrease of plant density. The 45cm intra-row spacing, showed significantly higher lint (%) than others. The main effect of intra-row spacing on seed index and lint index was not significant. On the other hand, variety Hamid and Burhan produced larger boll weight and higher seed index, but Khalifa and Wagar showed higher lint 3
index and lint%. Difference in number of boll/m² due to variety was not significant. Interaction effect was significant for number of boll/m² (in 21), boll weight (in 26) and lint index (in 27)- (Table 8b, c,d). Tables (6 and 7) show the main effects of variety and intra-row spacing on seed cotton and lint yield (kg/fed.), for the five seasons and combined. Yields were highest in the second season (91 kg seed cotton/fed.) followed by the third season (72 kg seed cotton/fed.) compared with the three other seasons (due to amount and distribution of rainfall during the growing season), Table 4. Generally, under the favorable conditions of seasons 27 and 28, and also, in the combined analysis, the difference between plant densities was not significant. But in dry seasons (26 and 29), yield was increased due to the narrow intra-row spacing. Both of Burhan and Khalifa produced significantly higher yields than the two other varieties (averaged over five seasons). Only the interaction effect was significant for lint yield during 26 (Table 8e), with variety Burhan more responsive to plant spacing compared to others. Fiber quality tests Fiber characteristics of three varieties as influenced by different intra-row spacing (for the 26 and 28 seasons) are shown on Tables 9 and 1. Comparing the two seasons, cotton fiber length was better in 28 than in 26, due to the adequate amount and distribution of rainfall. 2.5% span length and finesse (Mic.) were reduced by closer intra-row spacing, in 26 (due to shortage of rainfall). Differences in fiber properties due to plant spacing were not pronounced in the 28 season. Insect pest Count of insect pests as affected by variety and plant spacing are presented on Tables 11 and 12. The population of insect pests was higher during 26 than in 21. Variety Burhan showed significantly lower number of Jassid nymphs/1 leaves than Hamid and Khalifa (in 26). There was no significant effect for plant spacing on number of insect pest, in both seasons. Summary and Conclusion: Yield of cotton was greater in 27 and 28 than in 26, 29 and 21, due to seasonal variation. Cotton yield was affected more by season and variety than by plant spacing. Number of bolls/m² was increased with the increase of plant density, while boll weight (g) was decreased with the increase of plant density. The 45cm intra-row spacing, showed higher lint (%) than others. Seed index and lint index were not affected by plant spacing. The varieties Hamid and Burhan produced larger bolls and higher seed index, while Khalifa and Wagar showed higher lint index and lint%. In 27, 28 (wet seasons) and combined data, the differences between plant densities were not significant for yield. But in 26 and 29 (dry seasons), yield was increased due to the narrow intra-row spacing. Both varieties (Burhan and Khalifa) produced higher yields than the two others. 4
Recommendation: Based on the statistical analysis, the 15-45cm intra- row spacing (233-5524 plants/fed) were recommended and suggested for new cotton varieties in the rain-fed area of the Blue Nile State. References: Babiker, E. A. 1986. Annual Report of the Rahad Research Station, ARC, Sudan. Babiker, E. A. 1987. Annual Report of the Rahad Research Station, ARC, Sudan. Babiker, E. A. 1988. Annual Report of the Rahad Research Station, ARC, Sudan. Babiker, E. A. 24. Effect of plant density and spatial arrangement on growth, quality and yield of morphologically varying cotton varieties. Gezira j. agric. Sci. 2(1): 16-25. Burhan, H. O. 1967. Annual Report of the Gezira Research Station, ARC, Sudan. Fadda, N. R. 1961. Annual Report of the Research Division, Ministry of Agriculture, Sudan. Elhassan, O. M. A. and A. H. Abdalatif. 25. Effect of inter-row and intra-row spacing on growth, yield and fiber quality of two cotton varieties, under rainf-ed condition. Crop husbandry Committee Meeting, June, 25, Wad Medani, Sudan. Lazim, M. E. 1986. Annual Report of the Gezira Research Station, ARC, Sudan. Lazim, M. E. 1987. Annual Report of the Gezira Research Station, ARC, Sudan. Lazim, M. E. 1988. Annual Report of the Gezira Research Station, ARC, Sudan. Lazim, M. E. 1989. Annual Report of the Gezira Research Station, ARC, Sudan. Mustafa, A. M., Ahmed, N. E., Kenan, H. O. (24). Release of new high yielding and highly resistance to bacterial blight cotton varieties.arc, Variety Release Committee Meeting, Wad Medani, Sudan. Mustafa, A. M., Babiker, E. A. and Elhassan, O. M. (26). Proposal for the release of new high yielding and early maturing cotton cultivars for rain- grown sector in the Sudan. ARC, Variety Release Committee Meeting, Wad Medani, Sudan. Taha. M. A. 1962. Annual Report of the Research Division, Ministry of Agriculture, Sudan. Taha. M. A. 1963. Annual Report of the Research Division, Ministry of Agriculture, Sudan. 5
Table (1) Rainfall (mm) data as 1 days total, maximum and minimum temperature Cº and relative humidity (R.H.%), at Damazin, during 26-21 seasons. Element May June July Aug. Sep. Oct. Nov. 26 Rainfall (mm) 1-1 11-2 21-3 51 52 68 78 49 59 84 31 4 3 33 44 Total/month 13 146 192 65 77 Total/year 681 Mean. temp. Cº 3.7 29.3 28 26.9 26.8 28.4 26.8 R.H.% 52 62 72 78 72 68 48 27 Rainfall (mm) 1-1 11-2 21-3 11.5 54.5 37 11 81 136 11 127 94.5 37 Total/month 11.5 11 228 259 113 128 8 Total/year 849.5 28 Rainfall (mm) 1-1 - 47 34 82 41 36 11-2 - 9 134 82 2 21-31 2 9.5 5 115 32 42 Total/month 2 227 218 279 93 78 Total/season 915.5 Rainfall (mm) 29 1-1 - 56 12 125 31 22-11- 2-1 55 57-39 - 21-31 27 59 62 4 48 - - Total/month 27 125 129 222 79 61 - Total/season 643 Rainfall (mm) 21 1-1 58 86 Rare 16 14 26-11- 2 33 57 Rare 4 67 12-21- 31 34 37 4 25 9 21 - Total/month 125 18 4 81 18 59 - Total/season 665 Source: Damazin Meteorological Station. 54 47 12 74 54 8 6
Table (2) Actual plant population of four tested varieties, as affected by different intrarow spacings at Damazin, during 26-21 seasons Variety Intra row (cm) 26 27 28 29 21 Mean 1.Hamid 15 58138 5526 5621 47199 68863 57123 2. ~ 2 42768 39748 45625 43698 45747 43517 3. ~ 3 34142 29383 3436 32417 3372 32736 4. ~ 45 24422 24455 2397 25415 23238 24287 5.Burhan 15 56558 596 466 45717 67857 52167 6. ~ 2 4721 43526 3644 43827 48545 43793 7. ~ 3 356 35131 23451 31768 35891 32368 8. ~ 45 23571 249 16881 24248 23481 22454 9.Khalifa 15 57226 42462 6789 4639 73243 57426 1. ~ 2 43862 4272 5279 39548 49518 44696 11. ~ 3 3251 26189 354 3412 34797 32526 12. ~ 45 24179 2318 23999 26971 2258 23595 13.Wagar 15 - - - 38511 69958 54235 14. ~ 2 - - - 38481 438 41141 15. ~ 3 - - - 3412 3125 32564 16. ~ 45 - - - 22432 2336 22896 Table (3) Main effect means of varieties and intra-row spacings on three earliness components of cotton, at Damazin during 26-21 seasons. Factors Days to first flowering Days to first boll opening Number of nodes to first sympodia Variety Hamid 59a 15a 5.5a Burhan 58b 13b 5.4a Khalifa 58b 13b 5.4a Wagar 54c 98c 4.7b SE±.26.65.11 Level of sig. *** *** * Intra-row(cm) 15 58a 13a 5.4a 2 58a 13a 5.4a 3 57b 13a 5.4a 45 57b 13a 5.2b SE±.26.69.11 Level of sig. *** N.S. ** C.V.% 2.2 1.3 7.5 7
Table (4) Main effect means of varieties and intra-row spacings on plant height and number of sympodia of cotton, at Damazin during 26-21 seasons. Factors Variety Plant height (cm) Number of Sympodia/m² Hamid 8a 64a Burhan 74b 65a Khalifa 73b 66a Wagar 61c 66a SE± 1.35 3.1 Level of sig. *** N.S. Intra-row(cm) 15 71b 8a 2 73b 71b 3 76a 58c 45 76a 51d SE± 1.6 2.73 Level of sig. *** *** C.V.% 9.7 12.3 Table (5) Main effect means of varieties and intra-row spacings on yield components of cotton, at Damazin during 26-21 seasons. Factors Number of bolls/m² Boll weight- g Seed index g Lint index g G.O.T. % Variety Hamid 46a 4.5a 9.9a 5.3b 35b Burhan 48a 4.5a 1.1a 5.3b 34c Khalifa 5a 4.3a 9.3b 5.5a 36a Wagar 47a 3.7b 8.8c 5.4ab 36a SE± 2..7.8.6.27 Sig. level N.S. * *** * *** Intra-row(cm) 15 58a 4.1c 9.6a 5.3a 35b 2 52b 4.2c 9.6a 5.3a 35b 3 44c 4.4b 9.7a 5.3a 35b 45 38d 4.6a 9.7a 5.5a 36a SE± 1.72.6.8.7.3 Sig. level *** *** N.S. N.S. * C.V.% 19.5 1.1 6.6 7.6 3.7 Means within the same column followed by the same letter(s) are not significantly difference at p.5, according to Duncan Multiple Range Test. 8
Table (6) Main effect means of varieties and intra-row spacings on seed cotton yield, at Damazin during 26-21 seasons. Factors 26 27 28 29 21 Mean Variety Hamid 541b 91a 631b 233bc 43a 566b Burhan 613a 917a 761a 329a 441a 637a Khalifa 61a 912a 715a 257b 435a 61ab Wagar - - - 185c 44a 312c SE± 12.5 59.9 25.6 18.4 18.3 25.7 Sig. level *** N.S. ** *** N.S. ** Intra-row(cm) 15 66a 915a 73a 36a 378b 587a 2 594a 926a 68a 257ab 467a 585a 3 59ab 9a 76a 223b 454a 574a 45 55b 898a 694a 217b 42ab 556a SE± 14.4 66.9 29.6 18.4 18.3 3.8 Sig. level * N.S. N.S. ** ** N.S. C.V.% 8.5 25.5 14.6 25.4 14.7 21.5 Mean 585 91 72 251 43 56 Table (7) Main effect means of varieties and intra-row spacings on lint yield of cotton, at Damazin during 26-21 seasons. Factors 26 27 28 29 21 Mean Variety Hamid 199b 38a 217b 73bc 15a 198b Burhan 214a 318a 25a 12a 162a 218a Khalifa 225a 326a 255a 89ab 164a 223a Wagar - - - 66c 166a 116c SE± 4.7 21.4 8.8 6.1 6.8 7.3 Sig. level ** N.S. ** *** N.S. ** Intra-row(cm) 15 215a 314a 251a 11a 142b 25a 2 222a 327a 234a 85ab 173a 28a 3 28a 35a 24a 75b 17a 21a 45 25a 324a 238a 72b 157ab 199a SE± 5.5 24.5 1.2 6.1 6.8 9.9 Sig. level N.S. N.S. N.S. ** * N.S. C.V.% 8.9 26.8 14.7 25.4 14.7 22.2 Mean 213 317 241 83 161 23 Means within the same column followed by the same letter(s) are not significantly difference at p=.5, according to Duncan Multiple Range Test. 9
Table (8) Interaction effect of variety x intra-row spacing on some plant characteristics of cotton at Damazin, during 26-21 seasons Intra-row spacing (cm) Variety 15 2 3 45 a- Plant height (cm)- 29 Hamid 66a 63abc 64a 64a Burhan 53e 55de 56de 56de Khalifa 56de 59bcd 59bcd 62abc Wagar 56de 59bc 57de 58cd SE± 1.52* b- Number of bolls/m²- 21 Hamid 58cd 58cd 44efg 34g Burhan 72b 53de 5de 36g Khalifa 78ab 57cd 45efg 38fg Wagar 84a 67bc 48def 33g SE± 4.3* c- Boll weight (g)- 26 Hamid 4.9abcd 4.9abcd 4.7cd 5.2ab Burhan 4.4d 4.8bc 5.4a 5.abc Khalifa 4.3d 4.5d 4.7cd 5.2ab SE±.15** d- Lint index (g)- 27 Hamid 5.2bc 5.7a 4.5c 4.6c Burhan 5.8ab 5.3bc 5.2bc 6.4a Khalifa 5.2bc 5.3bc 5.8ab 5.3bc SE±.31* e- Lint yield (kg/fed)- 26 Hamid 196cd 25bcd 187d 28bcd Burhan 28bcd 234ab 223abc 19d Khalifa 241a 228ab 214abcd 216abcd SE± 5.5* 1
Table (9) Fiber characteristics of three tested cotton varieties as affected by different plant spacing at Damazin Research Farm, during 26 Varariety Intra-row spacing-cm 2.5% SL(mm) Finesse (mic.) Strength (HVI) Stickiness (SCT) 1-Hamid 15 25.3 4.3 27.8 2-Hamid 2 27.1 4.4 32.5 1 3-Hamid 3 25.7 4.4 29.8 4-Hamid 45 25.4 4.9 27.4 5-Burhan 15 26.6 4. 28. 6-Burhan 2 27.7 5.1 31.8 7-Burhan 3 27.4 5.3 3.2 8-Burhan 45 27.1 5. 27.8 9-Khalifa 15 24.8 4.4 29.2 1-Khalifa 2 27.8 4.1 29.4 1 11-Khalifa 3 26.8 4.3 34.3 12-Khalifa 45 27.1 5.1 31. Table (1) Fiber characteristics of three tested cotton varieties as affected by different plant spacing at Damazin Research Farm, during 28 Variety Intra- 2.5% UR% Fin. Strength Str. row pac SL (mic.) Stl (HVI) Stic. 1-Hamid 15 29.6 83 4.4 2.9 28.1 5 2-Hamid 2 29.6 84 4.3 19.2 25.7 3-Hamid 3 28.6 82 4.2 2.7 27.7 2 4-Hamid 45 28.7 83 4.1 19.5 26.1 4 5-Burhan 15 3.5 84 4.2 19.9 26.7 3 6-Burhan 2 29.8 82 4.6 19. 25.5 1 7-Burhan 3 28.7 82 4.3 2.7 27.7 1 8-Burhan 45 29.4 83 4.1 2.1 26.9 1 9-Khalifa 15 29.4 83 4.4 19.1 25.6 1-Khalifa 2 29.5 82 4.4 17.9 25.1 11-Khalifa 3 27.9 81 4.4 19.7 26.4 12-Khalifa 45 27.8 8 4.5 19. 25.5 2 11
Table (11) Effect of variety and intra-row spacing on insect population, at Damazin Research Farm during 26 season. Factor Hamid Burhan Khalifa African boll worm (larve+egg/1 leaves) Intra- row spacing-cm 15 6 9 6 2 8 8 5 3 6 1 8 45 5 7 6 SE± 1.7 Jassid (nymphs/1 leaves) Intra- row spacing-cm 15 3 36 44 2 42 24 42 3 44 28 4 45 44 3 42 SE± 4.6 Aphids (% infested plants) Intra- row spacing-cm 15 4 52 56 2 45 54 57 3 47 56 58 45 45 57 59 SE± 5.2 Flea beetle per 1 leaves Intra- row spacing-cm 15 2 4 2 2 4 6 4 3 2 2 6 45 2 4 4 SE± 1.3 Table (12) Effect of variety and intra-row spacing on insect population, at Damazin Research Farm during 21 season. Jassid (nymphs/1 leaves) Flea beetle per 1 leaves Treatments Hamid Burhan Khalifa Wagar Hamid Burhan Khalifa Wagar Intra- row spacing-cm 15 2 2 2 3 3 4 3 3 2 3 2 2 4 4 2 4 2 3 3 3 2 2 2 3 3 3 45 2 2 3 4 4 3 3 3 SE±.4.6 Intra- row spacing-cm 15 3 5 5 2 4 5 5 4 2 3 4 4 4 3 3 3 4 3 5 4 4 2 5 5 4 5 45 2 3 3 2 5 2 4 4 SE± 1.1 1.2 12