INDIAN MUSTARD (BRASSICA JUNCEA L.) A PROMISING OIL SEED CROP FOR LOW RAINFALL CROPPING REGIONS OF WESTERN AUSTRALIA C. P. Gunasekera 1, L.D. Martin 1, G.H. Walton 2 and K.H.M. Siddique 3 1 Muresk Institute of Agriculture, Curtin University of Technology, Northam, WA 61 <Lionel.Martin@curtin.edu.au>,<gunasekp@ses.curtin.edu.au> 2 Agriculture Western Australia, Locked Bag No. 4, Bentley Delivery Center, Bentley, 6983 <gwalton@agric.wa.gov.au> 3 Center for Legumes in Mediterranean Agriculture, University of Western Australia, Nedlands, WA 697 <ksiddiqu@agric.uwa.edu.au> ABSTRACT The effects of genotype, environment and their interaction on seed and oil yield of mustard (Brassica juncea L.) and canola (Brassica napus L.) was studied in field experiments at three sites in the low rainfall regions of Western Australia during 2 growing season. Early maturing genotypes of mustard has out yielded canola variety Oscar at all locations in all times of sowing and out yielded canola variety Monty in mid and late sowings. Seed yield and oil content of mustard and canola genotypes was greatest from the early sowing and reduced with delayed sowing. The effect of genotype and the genotype x environment (times of sowing) interaction on seed yield and oil content was highly significant at all locations. Early and short stature mustard lines were the best performers at all sites in all times of sowings. KEYWORDS content Adaptation, Genotype x Environment Interaction, Phenology, Seed yield, Oil INTRODUCTION In recent years grower interest towards canola in Australia has been high. However, adoption of canola in low rainfall regions of Western Australia is hindered by its low yield and poor performance in comparison with cereals, high cost associated with growing canola and the relative high risk of crop failure due to drought and Blackleg fungal disease (Marcroft, 1997). More recently Indian mustard (Brassica juncea) was thought more suitable for the commercial production, particularly in the low rainfall cropping regions of Australia (Kirk and Oram, 1978; Parker, 1999). Indian mustard has been identified as an alternative crop to canola as it shows greater tolerance to heat and water stress, (Niknam and Turner, 1999; Wright et al., 1996) and posses several agronomic advantages over canola (Kirk and Oram, 1978; Parker, 1999). Limited yield trials that have been carried out in the northern and central wheatbelt of Western Australia suggests that mustard has a higher yield potential in the medium and low rainfall regions (Oram and Kirk, 1995). However, considerable research on mustard is yet to be conducted in Western Australia before this crop can be recommended as an oilseed crop. This project was designed to study the adaptation of mustard in the WA cropping regions. As a part of a main study, the effects of genotype, environment and their interaction on the phenology, yield and oil content of mustard and canola was investigated in field experiments at three sites in the low rainfall regions of Western Australia.
MATERIAL AND METHODS Identical field experiments were conducted at three sites in the low rainfall cropping region of Western Australia at Merredin (31 o 29 S, 118 o 18 E), Mullewa (28 o 33 S, 115 o 25 E) and Newdegate (36 o 51 S, 119 o 1 E) in the relatively dry and short growing season of 2. Five mustard breeding lines (Table 1) varying in height, maturity and oil quality, together with two commercial canola varieties (Table 1) were sown at three times at all sites. Experiments were sown on 16 May, 9 June and 3 June at Merredin; 1 May, 13 June and 5 July at Mullewa and 16 June, 3 June and 14 July at Newdegate. Treatment combinations were arranged in a split-plot design with three replicates. Time of sowing was studied in the main plots and seven genotypes in the sub plots. Plots were sown with a cone seeder at the seed rate of 6 Kg/ha and were 1.44 m wide (8rows, 18cm apart) and 2m long. Double Superphosphate was direct drilled at 114 Kg /ha at sowing. Urea was applied at 65 Kg/ha very close to rows at sowing and at 87 Kg/ha four to five weeks after sowing. Weeds and pests were managed using recommended herbicides and insecticides where necessary. No major fungal diseases were observed at any of the sites. Daily maximum and minimum temperatures and daily rainfall were recorded at nearby weather station. Stand density was recorded at four weeks after sowing. Date of flowering, end of flowering and maturity was recorded from Merredin and Mullewa trials. Plots were machine harvested at maturity and seed oil content was determined. The data was statistically analysed by analysis of variance using Genstat statistical package. Table 1. Indian mustard and canola genotypes used in the study Genotype Description 887.1.6.1 Early, short, near canola quality mustard JM 25 Early to mid, tall, near canola quality mustard JM 33 Mid, tall, near canola quality mustard Muscon M-973 Early, short, medium condiment mustard 82 No 22-98 Early, short, medium condiment mustard Monty Early maturing canola Oscar Mid maturing canola RESULTS Weather Rainfall was largely confined to May to November growing season in all the sites. Significant amount of moisture was stored in the soil from relatively higher summer rainfall received by all the sites during early 2. During May to November period Merredin, Mullewa and Newdegate received total rainfall of 131.6, 95. and 143.6 mm, respectively. Rainfall in 2 was very low compared to long term average of 245, 261 and 266 mm during May to November at Merredin, Mullewa and Newdegate, respectively. Mullewa received very low rainfall in August compared to other two sites. All sites experienced a dry period in the end of the growing season. Maximum and minimum air temperatures were relatively higher at Mullewa compared to Merredin and Newdegate (Figure 1). No frost damage was noticed either in mustard or canola in any site. The early sown crop at Newdegate was subjected to wind erosion.
Figure 1. Total monthly rainfall - (mm) [histogram] and average monthly maximum [ ] and minimum [ ] temperatures at Merredin Mullewa and Newdegate in 2. Total monthly rainfall (mm) 16 12 8 Jan Merredin Mullewa Newdegate M ar M ay Jul S ep N ov 3 2 1 16 12 8 Ja n M a r M a y Ju l S e p N o v 3 2 1 16 12 8 M a r Ja n N o v S e p Ju l M a y 3 2 1 Temperature o C Month Phenology Flowering of all genotypes was relatively earlier at Mullewa than Merredin in all times of sowing (Table 2). The effect of genotypes, times of sowing and their interaction on the date of flowering at both sites were significant. There was no significant difference in flowering time between early and mid sowing of all genotypes except Oscar but all genotypes flowered significantly earlier in late sowing at Merredin. Flowering time of all mustard genotypes was consistent across times of sowing at Mullewa but that of canola genotypes was significantly and progressively reduced with delayed sowing. Table 2. Date of flowering (DAS) of seven genotypes of mustard and canola sown at three times at Merredin and Mullewa, WA in 2. Genotype Date of flowering at Merredin (DAS) Date of flowering at Mullewa (DAS) 887.1.6.1 84 83 77 81 63 65 62 63 JM 25 93 9 77 87 73 72 7 72 JM 33 1 1 84 95 71 73 7 71 Muscon M-973 66 69 7 68 6 62 58 6 82 No22-98 66 69 7 68 62 63 62 62 Monty 93 9 77 87 75 69 67 7 Oscar 114 93 91 99 16 87 79 91 Mean 88 85 78 84 73 7 67 7 LSD (P =.5) TOS = 4 VAR = 3 TOS X VAR = 5 VAR / Same levels of TOS = 5 TOS = 3 VAR = 2 TOS X VAR = 4 VAR / Same levels of TOS = 4 Seed yield Seed yield was significantly higher from early sowing and decreased as the sowing was delayed at all the sites (Table 3). Seed yield varied significantly (P<.1) among times of sowing at Merredin and Mullewa. At Newdegate seed yield was very low and consistent from all three times of sowing due
Table 3 Machine harvested yield and oil content of seven genotypes of mustard and canola sown at three different times at Merredin, Mullewa and Newdegate of WA in 2. Genotype Seed yield (t/ha) Oil content (%) Merredin 887.1.6.1 1.4.73.51.76 39.8 39. 37.9 38.9 JM 25.84.49.34.56 37.7 37.3 36.9 37.3 JM 33.68.41.29.46 36.8 36.6 36.5 36.6 Muscon M-973 1.1.79.61.8 36.7 36.7 36.5 36.6 82 No22-98.99.75.51.75 37.1 36.7 36.2 36.7 Monty.99.62.22.61 45.8 42.9.7 43.1 Oscar.68.35.11.38 41.7.6 38.5.3 Mean.89.59.37.62 39.4 38.6 37.6 38.5 LSD (P =.5) TOS =.24 VAR =.7 TOS X VAR =.24 VAR / Same levels of TOS =.12 TOS =.3 VAR =.3 TOS X VAR =.6 VAR / Same levels of TOS =.6 Mullewa 887.1.6.1 1.39.21.17.59 39.7 37.5 33.4 36.8 JM 25.99.11.29.47 37.5 36.8 35.8 36.7 JM 33.93.36.33.54 36.9 36.4 35.6 36.3 Muscon M-973 1.18.2.15.51 36.8 35.9 35.3 36. 82 No22-98 1.34.25.2.6 38.4 34.8 32.3 35.2 Monty 1.29.23.31.61 43.7 38.4 33.8 38.6 Oscar.98.21.16.45 38.7 34.8 33.4 35.6 Mean 1.16.23.23.54 38.8 36.4 34.2 36.5 LSD (P =.5) TOS =.28 VAR =..9 TOS X VAR =.28 VAR / Same levels of TOS =.17 TOS =.6 VAR =.8 TOS X VAR = 1.38 VAR / Same levels of TOS = 1.43 Newdegate 887.1.6.1.46.27.14.29 37.9 37.4 37.8 37.7 JM 25.27.13.5.15 37. 37. 37.5 37.2 JM 33.24.13.4.14 36.1 35.8 35.9 35.9 Muscon M-973.3.22.12.21 36.4 36.2 36.3 36.3 82 No22-98.36.2.14.23 36. 34.8 35.5 35.4 Monty.53.21.9.28. 41. 41.1.7 Oscar.2.9.3.11 38.1 38.8 37.1 38. Mean.34.18.9.2 37.4 37.3 37.3 37.3 LSD (P =.5) TOS =.22 VAR =.5 TOS X VAR =.22 VAR / Same levels of TOS =.8 TOS =.4 VAR =.3 TOS X VAR =.58 VAR / Same levels of TOS =.56 to the late break of the season and wind erosion experienced during germination and establishment. Seed yield differed (P<.1) among genotypes and genotype x environment (times of sowing) interaction was highly significant (P<.1) at all the sites. Early, short, near canola quality mustard line (887.1.6.6) was the best performer at Merredin and Mullewa. This line produced slightly lower
yield than Monty at Newdegate when sown early, but performed well in late sowings. Early, short condiment mustard lines, (Muscon and 82 No 22-98) also performed very well at all sites and times of sowing. Canola variety Monty performed better than Oscar at Merredin and Newdegate. Oscar gave higher yield than Monty did, when sown early at Mullewa but performed poorly in late sowings. There was significant correlation between seed yield and final above ground biomass production (r 2 =.9), and harvest Index (r 2 =.6) at Merredin, where these two measurements were taken (Gunasekera et al 21). Oil yield Oil content varied significantly (P<.1) among times of sowing at Merredin and Mullewa, but was consistent across times of sowing at Newdegate. Oil content was highest from the early sowing and progressively reduced with delayed sowing regardless of the genotype (Table 3). Oil content varied significantly (P<.1) among genotypes and the genotype x environment interaction was highly significant (P<.1) at all three sites. Monty produced the highest content of oil at all sites regardless of the sowing time. DISCUSSION Experiments with oilseed Brassicas involving variation in sowing date have highlighted marked adverse effects on growth, development, yield and oil content (Heenan and Armstrong, 1993; Mendham et al., 1981; 199) and in most instances yield declines with later sowings in a Mediterranean environments. Similar results were observed at all three sites in this study. It is well known that the differences in response to sowing date apparently reflect the difference in flowering time between genotypes (Thurling, 1974; 1991). Irrespective of the fact that Mullewa received relatively lower total rainfall during May to November period, seed yield was highest at Mullewa in the first sowing than at the other two sites. Early sown crops at Mullewa flowered early and had relatively longer period for the accumulation of pre and post anthesis biomass for the completion of seed development before the onset of terminal drought stress. Though Newdegate received highest rainfall than the other two sites, seed yield of all times of sowing was lowest at Newdegate. Rainfall at Newdegate was confined only to June, July and August. Due to late break of the season crops were sown late at Newdegate and after flowering there was very little rainfall at this site for the completion of seed development. As reported in many other studies soil water deficits during a 15-day period after anthesis, when seeds are most likely to abort, have the greatest impact on yield of oilseed Brassicas (Mendham et al., 1981; Tayo and Morgan, 1979). Water deficits during flowering and early pod development reduces yield of B. napus and B. campestris by reducing both pod number per plant and seed number per pod (Richards and Thurling, 1978). Yield of mid and late sowings was higher at Merredin at the than other two sites as Merredin received well distributed rainfall during the growing season. Earlier flowering at Mullewa was due to relatively higher maximum and minimum temperatures at Mullewa than at the other two sites. Superior performance and the greater survival of mustard in late sowings over canola confirms its reputation for the greater tolerance to heat and water stress in this environment. CONCLUSION This study demonstrates that Indian mustard is a promising oil seed crop for low rainfall cropping regions of South Western Australia. When phenologically adapted genotypes and appropriate sowing times are followed, Indian mustard will provide a profitable crop option for growers in the low rainfall short season regions of South Western Australia.
ACKNOLEDGEMENTS Mustard germplasm was kindly supplied by the National Mustard Breeding Program at Horsham, Victoria. We greatly appreciate the technical assistance of Tammi Short, Ruwan Warnakula Dirranie Kirby, Research support unit Mullewa, Steve Crook, Research support unit Newdegate and Greg Bunker, Research support unit Merredin. REFERENCES Gunasekera, C.P., Martin, L.D., Walton, G.H. and Siddique K.H.M. (21). Growth and seed yield components of Indian mustard (Brassica juncea L.) and canola (Brassica napus L.) in short season Mediterranean type environment. In "12th Australian Research Assembly on Brassicas". Heenan, D. P. and Armstrong, E. L. (1993). Sowing time effects on yield and quality of canola and linseed. In "9th Australian Research Assembly on Brassicas" (N. Wratten and R. J. Mailer, eds.), pp. 83-86, Wagga Wagga, New South Wales. Kirk, J. T. O. and Oram, R. N. (1978). Mustards as possible oil and protein crops for Australia. The Journal of the Australian Institute of Agricultural Science 44, 143-156. Marcroft, S. (1997). Canola - Indian mustard potential for low rainfall cereal growing zones. In "11th Australian Research Assembly on Brassicas", pp. 124-127, Perth. Mendham, N. J., Russell, J. and Jarosz, N. K. (199). Response of sowing time of three contrasting Australian cultivars of oil seed rape (Brassica napus). Journal of Agricultural Science, Cambridge 114, 275-283. Mendham, N. J., Shipway, P. A. and Scott, R. K. (1981). The effects of delaying sowing and weather on growth, development and yield of winter oil seed rape (Brassica napus). Journal of Agricultural Science, Cambridge 96, 389-416. Niknam, S. R. and Turner, D. W. (1999). A single drought event, at different stages of development, has different effects on the final yield of Brassica napus cv. Monty and B. juncea line 397-23-2-3-3. In "1999 Oilseed Crop Updates" (G. Shea, ed.), pp. 14-15. Agriculture Western Australia, Northam, WA. Oram, R. N. and Kirk, J. T. O. (1995). Developing double low Indian Mustard for the Australian Wheatbelt. In "1th Australian Research Assembly on Brassicas" (T. D. Potter, ed.), pp. 9-93, Struan, South Australia. Parker, P. (1999). The mustard industry in Australia- Opportunities for a new oilseed. In "1999 Oilseed Crop Updates" (G. Shea, ed.), pp. 12-13. Agriculture Western Australia, Northam, WA. Richards, R. A. and Thurling, N. (1978). Variation between and within species of rapeseed (Brassica campestris and B. napus) in response to drought stress II. Growth and Development under natural drought stresses. Australian Journal of Agricultural Research 29, 479-9. Tayo, T. O. and Morgan, D. G. (1979). Factors influencing flower and pod development in oil seed rape (Brassica napus). Journal of Agricultural Science, Cambridge 92, 363-373. Thurling, N. (1974). Morphological determinants of yield in rapeseed (Brassica campestris and Brassica napus) I. Growth and Morphological characters. Australian Journal of Agricultural Science 25, 697-71. Thurling, N. (1991). Application of the ideotype concept in breeding for higher yield in the oilseed Brassicas. Field Crops Research 26, 21-219. Wright, P. R., Morgan, J. M. and Jessop, R. S. (1996). Comparative adaptation of canola (Brassica napus) and Indian mustard (B.juncea) to soil water deficits: Plant water relations and growth. Field crop Research 49, 51-64.