D.R. Singh

Estimation of proximate composition, micronutrients and phytochemical compounds in traditional vegetables from Andaman and Nicobar Islands.

In present study, 10 preferred traditional vegetables from Andaman and Nicobar Islands, India, were analysed for nutritional profiles. Moisture content in their edible parts ranged from 83.43 to 94.78%. Maximum ash content was recorded in Portulaca oleracea, crude protein in Colocasia esculenta, crude fibre in Eryngium foetidum and fat in E. foetidum. Phosphorus was maximum in Ipomea aquatica, potassium in C. esculenta, zinc, calcium and manganese in Centella asiatica, copper in Sauropus androgynous, sodium and iron in P. oleracea, magnesium in Amaranthus viridi and cobalt in C. esculenta. Maximum polyphenol was recorded in Hibiscus sabdariffa, carotenoids in A. viridi, ascorbic acid in Saursops androgynus, anthocyanin in C. esculenta and chlorophyll in S. androgynus. Antioxidant activity was maximum in P. oleracea. Positive correlation was observed between polyphenol and tannin content and also between antioxidant activity and photochemicals. The developed nutritional profiles is being used in health and nutrition related schemes in Islands.

Estimation of phytochemicals and antioxidant activity of underutilized fruits of Andaman Islands (India).

The present study aimed to determine the antioxidant activity and phytochemical contents in 10 underutilized fruits of Andaman Islands (India) namely Malpighia glabra L., Mangifera andamanica L., Morinda citrifolia L., Syzygium aqueum (Burm.f) Alst., Annona squamosa L., Averrhoa carambola L., Averrhoa bilimbi L., Dillenia indica L., Annona muricata L. and Ficus racemosa L. The antioxidant activity varied from 74.27% to 98.77%, and the methanol extract of M. glabra showed the highest antioxidant activity (98.77%; inhibitory concentration, IC50 = 262.46 μg/ml). Methanol was found to be a better solvent than acetone and aqueous for estimating the antioxidant activity. M. glabra was found to be rich in phytochemicals viz. polyphenol (355.74 mg/100 g), anthocyanin (91.31 mg/100 g), carotenoids (109.16 mg/100 g), tannin (24.39 mg/100 g) and ascorbic acid (394.23 mg/100 g). Carbohydrate content was estimated to be highest in M. glabra (548 mg/100 g). Phenols, tannins, anthocyanins and carotenoids contents showed positive correlation (r2 = 0.846, r2 = 0.864, r2 = 0.915 and r2 = 0.806, respectively) with antioxidant activity. The information generated in present study will be useful for bioprospecting of underutilized fruits of Andaman Islands.

Changes in phytochemicals, anti-nutrients and antioxidant activity in leafy vegetables by microwave boiling with normal and 5% NaCl solution

The present study investigated the changes in phytochemicals and antioxidant activities in 25 leafy vegetables with two common boiling practices viz., with 5% NaCl solution (BSW) and normal water (BNW) in a domestic microwave oven. Fresh samples (100g) were rich in polyphenols (58.8-296.9mg), tannin (402.0-519.4mg), flavonoids (148.9-614.4mg), carotenoids (69.0-786.3mg), anthocyanin (11.7-493.7mg) and ascorbic acid (245.0-314.2mg). Microwave boiling significantly (p<0.05) decreased/increased phytochemicals but none of the compounds followed same trend in all vegetables. Boiling process reduced anti-nutrients from fresh samples (FS) as observed for nitrate (4.5-73.6% by BSW and 22.5-98.8% by BNW); phytate (6.2-69.7% by BSW and 10.6-57.3% by BNW) and oxalate (14.7-88.9% by BSW and 14.5-87.3% by BNW) but saponin increased in 18 vegetables by BNW while 8 vegetables by BSW. The study revealed differential pattern of change in phytochemical matrix and anti-nutrients in vegetables by microwave boiling which will help in devising efficient cooking practices and contribute in health and nutritional security.

Analysis of Perspectives of Self-sufficiency in Vegetable Production Under Tropical Conditions

The government of India is promoting local vegetable production in Andaman and Nicobar Islands in a policy of sustainable development on tropical bay islands. There has been an increase in area and productivity of vegetables and reduced import of vegetables from the mainland. Improved technologies have been transferred to vegetable farms. However, the majority of farmers rely on private agencies for inputs and marketing activities that limit profits. Lack of cold transport, storage facilities, modern collection centers, and processing industry are still challenges to vegetable growers on islands. Use of good agricultural practices for vegetables includes limited use of synthetic chemicals in the island ecosystem. The pace of adoption of improved practices in vegetables needs to be enhanced to ensure off-season availability. Many island cultures employ organic methods by default and a small amount of effort can establish them as organic hubs for vegetable production. Rising tourism and increasing import cost of vegetables increased the necessity of structural changes in production to make islands self-sufficient in vegetable production.

Diversity of 21 taro (Colocasia esculenta (L.) Schott) accessions of Andaman Islands

The genetic diversity of taro (Colocasiaesculenta (L.) Schott.) accessions growing naturally in Andaman Islands was analysed using morphological and DNA markers. Twenty one representative samples of C. esculenta from different parts of Islands in addition to three commercial varieties as reference genotypes were used in study. About 63% phenotypic variation was observed in C.esculenta A total number of 491 amplified fragments were obtained of which 347 showed polymorphic banding patterns. The accessions were grouped into two major clusters with both RAPD and ISSR markers with 56 and 57% diversity, respectively. The reference genotypes were grouped into one group and island population in other cluster. Both marker systems divided population into two sub clusters and showed correlation with morphological parameters. The diversity pattern observed in present study showed rich genetic diversity of C.esculenta in Andaman Islands provided simple strategy for reducing repeatability of taro germplasm in gene banks. The study also suggested pre-evaluation of germplasm using molecular and morphological markers to enhance efficiency of exploration trips.

Eco-friendly management modules for bacterial wilt (Ralstonia solanacearum) of tomato for protected cultivation in a tropical island ecosystem

Bacterial wilt (Ralstonia solanacearum) is the most threatening disease of tomato in tropical regions and causes great loss to the tomato industry in open and protected cultivation. This study aimed to develop an eco-friendly management module for bacterial wilt of tomato for the Andaman and Nicobar Islands in India. For this, three experiments were conducted at the Central Agricultural Research Institute, Port Blair, Andaman and Nicobar Islands, India, on genotype screening, grafting technique and growing media during 2009–2012. Among 70 genotypes tested, none were found to be resistant against R. solanacearum and had high level of incidence (41.5–94.2%). Graft compatibility of tomato was observed with Solanum torvum and Solanum melongena, which showed high level of bacterial wilt tolerance with 0.0% and 5.5% incidence, respectively. Cocopeat-based growing media significantly (p < 0.05) reduced bacterial wilt incidence (15.0–45.0%) compared with controls (40.0–56.7%) in potted tomatoes. Fruit yield from individual plants was negatively affected in grafted plants while a significant (p < 0.05) increase was recorded from tomatoes in cocopeat-based growing media. Both options reduce wilt incidence significantly (p < 0.05) and maintained the plant population with increased yield per unit area. These trials suggested three modules against bacterial wilt; first, tolerant genotype+grafting on S. torvum or S. melongena rootstocks+growing on cocopeat–vermicompost–lime (1.0:1.0:0.01) media; second, tolerant genotype+cocopeat–vermicompost–lime (1.0:1.0:0.01) media; and third tolerant genotype+grafting on S. torvum or S. melongena rootstocks. These are cost-effective and locally available eco-friendly modules, which can be adopted in bacterial wilt prone areas of tropical islands.

Genetic Diversity in Drumstick of Andaman Islands and Their Relatedness with Probable Introduction Sites from Mainland India

Abstract The study investigated genetic diversity in Moringa oleifera Lam. samples (63) from nine islands in Andaman and Nicobar Islands (India) and their relatedness with samples (5) from their probable source regions in mainland India. The polymerase chain reaction analysis with polymorphic random fragment polymorphic DNA (RAPD) (5) and inter simple sequence repeat (ISSR) (20) markers generated 987 and 4190 amplicons, respectively. The RAPD analysis resulted into two main and eight sub-clusters and ISSR markers generated two main and five sub-clusters. Extent of similarity in 68 samples was revealed to be 49% by RAPDs to 53% by ISSR markers. Average polymorphism information content (PIC) value ranged from 0.47 to 0.50 for the studied markers. Maximum collections from the islands were grouped along with samples from Tamil Nadu, Andhra Pradesh and Kerala which suggest high level of genetic relatedness. The information on influence of ‘isle factor’ in genetic divergence of introduced drumsticks is useful for continuance of studies on genetic changes for adaptation.