Antioxidants in tomato (Lycopersium esculentum) as a function of genotype

Consumption of tomato products has been associated with decreased risk of some cancer types. Epidemiological findings confirm the observed health effects due to the presence of varied antioxidants in tomato. The bio-antioxidant content and antioxidant activity of 12 tomato genotypes was therefore studied. Significant differences were found between lycopene, ascorbic acid and phenolic contents among various genotypes. Lycopene and ascorbic acid contents showed 1–4 fold and 1–2 fold variation on both fresh and dry weight basis, respectively. Antioxidant activity was found to vary significantly among genotypes. In both free radical quenching assay and FRAP assay, significant activity was found. Activity was higher in the hexane fraction containing lycopene than the methanol fraction containing phenolics. Tomato peels, in addition to lycopene, contain significantly high amounts of ascorbic acid and phenols. Cherry tomatoes, particularly variety 818 cherry, with the highest contents of antioxidants (lycopene, ascorbic acid and phenols) and highest antioxidant activity represents a valuable genotype not only for improving the status of dietary antioxidants in our diet but also for increasing nutritional value through germplasm enhancement programmes. The cherry varieties also merit considerable attention for processing because of their high total soluble solids and titrable acidity. [1]

In Vitro screening of tomato genotypes for drought resistance using polyethylene glycol

Drought is a major abiotic factor that limits plant growth and productivity. Tomato is an important vegetable crop and area under production is limited by irrigation water scarcity. Effort was made to screen tomato germplasm under in vitro condition using polyethylene glycol (PEG) at four concentrations (0, 20, 40 and 60 g/l) with two replications in factorial CRD. Important seedling characters like root length and weight; shoot length and weight were recorded. Drought resistant mutant derivatives and hybrid produced using mutant derivative as female parent performed significantly superior for root characters. Decrease in seedling growth was worth notice with increasing concentration of PEG indicating precise nature of the in vitro screening. Mutant hybrid and its derivatives were observed with outstanding ability to continue root growth under in vitro stress conditions indicating there ability to fight with sever water stress situation. These results were further confirmed for early indication traits in raised bed seedlings and fully-grown mature plants under field conditions. At all three experimental conditions, mutant derivatives and hybrids performed better than cultivated genotypes under all levels of water stress. Based on results, Hy-3 and MTG 1-4 were found to be drought resistant due to there remarkable performance at all levels of water stress. This in vitro screening method is potential and cost effective method to screen large set of germplasm within very less time period and accurately. [2]

Determination of screening techniques to salinity tolerance in tomatoes and investigation of genotype responses

In order to determine the predictive screening parameters that can be applied at early development stages of tomato plants, 55 tomato genotypes were grown in nutrient solution with 200 mM NaCI. The relationships among the salinity scale classes based on the visual appearance and shoot Na+ accumulation, K+/Na+ and Ca2+/Na+ ratios and shoot-root dry weights were investigated. Tomato genotypes differed greatly for shoot Na+ concentration and salinity scale classes were significantly correlated with Na+ concentrations. Higher shoot Na+ concentrations indicated higher shoot damage. Shoot K+/Na+ and Ca2+/Na+ ratios were significantly correlated with the salinity scale classes. The higher shoot K+/Na+ and Ca2+/Na+ ratios indicated lower shoot damage. Tomato genotypes grown under 200 mM NaCI stress showed significant variations in shoot and root dry weights. However, no significant correlations were found between the shoot-root dry weight and the scale classes and Na+ concentration and the ion ratios investigated. These may indicate that plant shoot and root dry weights were independent of salt tolerance at the growth stage reached in this study. [3]

Screening and Identification of Salt Tolerant Genotypes Based on Agromorphogenic Traits of Tomato (Solanum lycopersicum L.)

A pot experiment was carried out to observe the performances of fifteen tomato genotypes under three different salinity treatments in the net house of Genetics and Plant Breeding Department of Sher-e-Bangla Agricultural University, Dhaka during November 2013 to March 2014. Two factorial experiment comprised of fifteen tomato genotypes viz. G1 (BD-7289), G2 (BD-7291), G3 (BD-7298), G4 (BD-7748), G5 (BD-7757), G6 (BD-7760), G7 (BD-7761), G8 (BD-7762), G9 (BD-9011), G10 (BD-9960), G11 (BARI Tomato-2), G12 (BARI Tomato-3), G13 (BARI Tomato-11), G14 (BARI Hybrid Tomato-4), G15 (BARI Hybrid Tomato-5) and three salinity treatments T1 (control), T2 (8 dS/m), T3 (12 dS/m) were laid out in Completely Randomized Design (CRD) with three replications. Seedlings were transplanted 30 days age to leading plastic pots, and two salinity treatments 8 dS/m and 12 dS/m were applied after seven days of transplanting. The results revealed that tomato genotypes and salinity treatments both significantly different with the agro-morphogenic traits of the tomato plant. Nearly all traits reciprocated negatively as the salinity level increased except days to first flowering and maturity. Average fruit weight was increased in genotype G8 for both the stresses than the control condition. Yield per plant was recorded in the same G8 genotype for T2 and reduced the minimum for treatment T3. Therefore, genotype G8 could be recommended for higher yield in the coastal regions of Bangladesh. These genotypes could also be served as parent material for future hybridization or genetic transformation program. [4]

Impact of Drought on Chlorophyll, Soluble Protein, Abscisic Acid, Yield and Quality Characters of Contrasting Genotypes of Tomato (Solanum lycopersicum)

Impact of drought stress on chlorophyll, chlorophyll fluorescence (Fv/Fm), chlorophyll stability index (CSI), soluble protein, abscisic acid (ABA), yield and quality of tomato (Solanum lycopersicum) genotypes was investigated for the assessment of drought tolerance under field conditions in rainout shelter. The drought condition was created first day from transplanting based on Irrigation water (IW):Cumulative Pan Evaporation (CPE) of soil. Experiment was laid out with 10 genotypes by adopting FRBD with three replications and two treatments of 1 IW:CPE and 0.5 IW:CPE. The result revealed that the reductions in chlorophyll content, Fv/Fm, chlorophyll stability index (CSI), soluble protein and yield were noticed at drought condition (0.5 IW/CPE). The genotypes LE 114, LE 57, and LE 118 which showed significantly less reduction in the above parameters during drought were considered as drought tolerant. ABA content and quality characters such as total soluble solids (TSS), lycopene content were increased under drought condition. Genotypes LE 1 and LE 125 which recorded the lowest chlorophyll content, Fv/Fm, CSI, soluble protein and higher ABA content ultimately poor yield were considered as drought susceptible. [5]

Reference

[1] George, B., Kaur, C., Khurdiya, D.S. and Kapoor, H.C., 2004. Antioxidants in tomato (Lycopersium esculentum) as a function of genotype. Food chemistry, 84(1), pp.45-51.

[2] Manoj, K. and Uday, D., 2007. In vitro screening of tomato genotypes for drought resistance using polyethylene glycol. African Journal of Biotechnology, 6(6).

[3] Dasgan, H.Y., Aktas, H., Abak, K. and Cakmak, I., 2002. Determination of screening techniques to salinity tolerance in tomatoes and investigation of genotype responses. Plant Science, 163(4), pp.695-703.

[4] Haq, M., Zeba, N., Akter, R., Begum, B. and Harun-Ur-Rashid, M. (2017) “Screening and Identification of Salt Tolerant Genotypes Based on Agromorphogenic Traits of Tomato (Solanum lycopersicum L.)”, Annual Research & Review in Biology, 18(4), pp. 1-11. doi: 10.9734/ARRB/2017/36855.

[5] Sivakumar, R., Nandhitha, G. K. and Nithila, S. (2018) “Impact of Drought on Chlorophyll, Soluble Protein, Abscisic Acid, Yield and Quality Characters of Contrasting Genotypes of Tomato (Solanum lycopersicum)”, Current Journal of Applied Science and Technology, 21(5), pp. 1-10. doi: 10.9734/BJAST/2017/34347.