SODIUM CONTENT JUICE AND JAGGERY QUALITY OF SUGARCANE GENOTYPES UNDER SALINITY

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1 e Journal of Biological Sciences Volume: 1, Issue 1 (December 2009) ISSN: , EISSN: All rights reserved. SODIUM CONTENT JUICE AND JAGGERY QUALITY OF SUGARCANE GENOTYPES UNDER SALINITY S.Vasantha 1, R.Gomathi 1 and P.Rakkiappan 2 Sugarcane Breeding Institute, Coimbatore 1 Department of Plant Physiology, 2 Department of Soil Science &Agricultural Chemistry ABSTRACT Sugarcane genotypes tolerant to salinity were tested for jaggery quality that seems to differ under salinity. Tolerant types were rated based on better biomass production, cane yield and other physiological parameters viz., photosynthetic rate, leaf area index etc., under higher soil salinity. Among the tolerant genotypes difference in jaggery quality was recorded with respect to net rendement value(%), colour and taste under salinity, grading tolerant genotypes as good, poor and unsuitable for jaggery preparations, when grown in saline soil. INTRODUCTION: Sugarcane is one of the important commercial crops used for the manufacture of sugar, jaggery and other products. Jaggery provides an alternative market to sugarcane growers. About 26% of the sugarcane produced is diverted for jaggery production 1. The quality of the jaggery is dependent on the cane juice which in turn is determined by the variety and the environment in which the cane is grown. The adverse conditions viz., salinity, drought etc., affect cane yield and quality. Soil salinity has a profound impact on sugarcane crop and the crop is rated moderately sensitive 2. However, tolerant genotypes compromises either in yield or quality and thus able to perform under adverse situations, through various physiological and biochemical mechanisms. Salinity tolerant genotypes are identified at Sugarcane Breeding Institute, Coimbatore, in simulated saline conditions in micro plots. The identified tolerant types are better performers in terms of cane yield and sugar yield. However jaggery characteristics are not assessed under saline conditions. It is in this purview that the varietal selection for the end product utilisation assumes importance. A study was undertaken to find out the effect of salinity on the quality of jaggery with different genotypes of sugarcane. MATERIALS AND METHODS Sugarcane genotypes tolerant to salinity (Co 94012,,,,, and ) and a sensitive genotype () were planted in micro plots salinised and maintained during the crop season to a EC value of 8 ds m -1 with a salt solution of NaCl, CaCl 2 and Na 2 SO 4 in the ratio of 2:2:1. Photosynthetic rate was recorded with portable photosynthesis system (ADC model LCA-4, UK) in the first Top Visible Dewlap (TVD). Total dry matter (TDM) and leaf area index(lai) were recorded during grand growth phase and number of millable canes (NMC), juice quality parameters, cane yield and sugar yield were recorded at harvest. Jaggery was prepared following standard protocol for quality evaluation. Jaggery was graded based on the net rendement value (NR), calculated using the formula. NR= (Pol per cent-reducing sugars per cent) - (3.5 x Ash per cent). 33

2 e Journal of Biological Sciences RESULTS AND DISCUSSION Physiological parameters viz., leaf area index and photosynthetic rate, which govern the biomass production, during grand growth phase, varied significantly between the treatments as well as among the genotypes (Table1). In control plants the photosynthetic rate ranged from (µmolm -2 s -1 ) in Co to 19.2 (µmolm -2 s - 1 ) in while, in salinity treatment it varied from (µmolm -2 s -1 ) in to 17.9 (µmolm -2 s -1 ) in. Reduction in photosynthetic rate ranged from 4.5 (Co 94012) to 18 () per cent. Leaf area index reduced under salinity in all the genotypes (Table 1). Significant interaction existed between treatments and genotypes indicating the influence of salinity and genotypic response. Total dry matter production reduced under salinity with significant genotypic variation (Table1). TDM production was maximum in (2.75kg/m 2 ) and least in (2.38kg/m 2 ) in control plots while, in saline plots the TDM production varied from 2.42kg/m 2 (Co 94012) to 0.68 kg/m 2 ( ). Salinity sensitive clones can be distinctly identified from the biomass production data at grand growth phase. Reduction in stalk yield, number and weight was reported due to salinity 3-6. Higher photosynthetic rate coupled with higher leaf area index is a positive signature for higher dry matter production. Stem being the economic sink, higher dry matter allocation is essential for higher yield. Therefore, photosynthetic rate, LAI and TDM at grand growth phase is a major regulating factor of cane yield. Under stress condition varieties due to their inherent potential either maintain high photosynthetic rate, LAI and TDM and rated as tolerant or with reduced Pn,LAI and TDM ends up as sensitive types. In the present study a sensitive variety has been clearly demarcated based on the above physiological parameters. However, among the tolerant genotypes variations for quality parameters have been recorded, which renders them as better varieties for jaggery making or unsuitable for jaggery purpose. Table 1: Influence of salinity on Physiological parameters Genotype Photosynthetic rate* (µmolm -2 s -1 ) Leaf Area Index* Biomass (kg/m 2 )* Co Significant(p>5%) SEd CD SEd CD SEd CD Genotype Treatment GxT The electrical conductivity of the juice at harvest increased in all the genotypes due to increased accumulation of Na and K ions causing a reduction in sucrose per cent juice (Fig. 2a&b). In genotypes Co 94012, and the increase in Na and EC was marginal and consequently there was not much reduction in juice sucrose content under salinity. Increase in EC of the cane juice was observed in cane crop irrigated with saline water 7. Juice sodium content influence the jaggery quality to a greater extent as evidenced from fig. 2b and table 2. 34

3 Co Co e Journal of Biological Sciences Table 2: Jaggery quality as influenced by salinity Variety NR value Grade* Colour Control Salinity Control Salinity Control Salinity Co A1 A1 light brown light brown A2 B light brown brown A2 B light brown brown 64.4 No A2 -- light brown -- solidification A2 A2 light brown brown A2 C light brown brown A1 A1 golden yellow golden yellow *A1= > 65 %, A2 = > 60 and < 65, B = >45 and < 60, C = <45. Fig. 2a. Juice quality as affected by salinity Control Salinity Sucrose% EC ds/m-1 35

4 Co Co mg/100 ml e Journal of Biological Sciences Fig. 2b: Juice quality as affected by salinity Control salinity Na K However, well pronounced differences in jaggery quality as indicated by net rendement value and colour (Plate1) was observed among the tolerant genotypes (Table1). Among the tolerant genotypes, and produced jaggery with poor grade, colour and taste since the juice quality characters were affected. The genotypes Co and produced good quality jaggery even under salinity as sodium and chloride content increased only marginally while cane yield and juice quality were not affected. There was no setting of jaggery in the genotype under salinity, while under control produced quality jaggery. The colour and taste of the jaggery are the deciding factors for the consumer and decide the market value of the jaggery. In the context of sizeable area of sugarcane being grown under saline soils, there is a need for identification of genotypes like Co and able to produce good quality jaggery under saline conditions. Content of Na in juice is to be considered essential new criteria than salinity tolerance per se in identifying genotypes suitability exclusively for jaggery making purpose. 36

5 e Journal of Biological Sciences Plate1: Jaggery from Salinity tolerant genotypes of sugarcane Control Salinity Control Salinity Co Control Salinity 37

6 e Journal of Biological Sciences REFERENCES 1. Navadkar, D. S., Birari, K.S. and Padigre, B. V., Export market potential of cane jaggery in India. Agricultural Marketing,2004 January-March, Maas E.V., Crop salt tolerance. In Agricultural salinity assessment and management. (ed) K.K. Tanji. Am. Soc.Civil Eng., New York (1990) Bernstein, L., Francois L.E., and Clark, R.A., Salt tolerance of NCo varieties of sugarcane. I sprouting, growth and yield. Agron. J. 1966, 58, Ginoza, H. and Moore, P.H., Screening sugarcane varieties for tolerance to salinity. Report of the Hawaiian Sugar Technologists. 1985, 43, FE5-FE6. 5. Rizk, T.Y., and Normand, W.C. Effects of salinity on Louisiana sugarcane. Int. Sugar J, 1969, 71, Syed, M M. and El-swaify, S.A. Effect of saline water irrigation on NCo 310 and H cultivars of sugarcane : I Growth parameters. Trop.Agric. 1972, 49, Thomas, J.R., Salinas, F.G. and Oerther, G.F. Use of saline water for supplemental irrigation of sugarcane. Agron. J. 1981, 73,