Taxonomic studies on leafhopper fauna associated with rice ecosystems in Tripura

ABSTRACT A study was taken up during 2009 -10 to collect and identify the leaf hoppers associated with rice ecosystem of Tripura region and thereby prepare key for identification. Collection revealed that nineteen leafhoppers are associated with rice crop ecosystem in different zones of Tripura state in India, which were identified subsequently. A key for distinguishing these leafhoppers along with illustrations has been provided

Seaweed resources of the Tuticorin-Tiruchendur coast, Tamil Nadu, India

The southern coast of Tamil Nadu (Mandapam to Kanyakumari) supports luxuriant growth of economic seaweeds. The entire indigenous phycocoUoid industry of the country gets the raw material from this region and during the last two decades, due to indiscriminate harvesting, there has been over-exploitation of the resource. The present paper deals with survey conducted in the first sector from Tuticorin to Tiruchendur during December 1986—March 1987. In this study 58 species of marine algae were recorded of which 7 belong to Chlorophyta, 12 to Phaeophyta and 39 to Rhodophyta besides 3 species of seagrasses namely Cymodocea seiriilata, Halophila ovalis and //. ovata within 650 sq. km area surveyed. The total standing crop of the seaweeds was estimated at 9,100 tonnes (wt.). The estimates for the dominant species are Dictyota maxima 530 t, Sargassum tenerrium 640 t, D. bartayresiana 8601, Selieria rebusta 2,0901 and Hypnea valemiae 2,4301. The seaweed potential for commercial exploitation has been briefly discussed

Seaweed resources off Tamil Nadu coast: Sector II. Alanthali - Manapad and Vembar – Nallathanni Thivu

The seaweeds are used for the production of polysaccharides such as agar, algin, carragennan and they are harvested from intertidal regions along the southeast shores of India. The resource potential from intertidal regions was estimated (Anon 1978

Distribution of sea weeds off Kattapadu - Tiruchendur coast, Tamil nadu

The present paper deals with the distribution of seaweeds and seagrasses during the deep sea survey conducted in the first sector from Kattapadu to Tiruchendur in Tamil Nadu coast between December 1986 and March 1987 covering an area of 650 sq.km. In thiS survey. 58 species of marine algae \\ere recorded. of which 7 belong to Chlorophyta. 12 to Phaeophyta and 39 to Rhodophyta. Three species of seagrasses vi z. Cymodocea serrl/lata. Halophila ovails and H. ovala were also recorded at the depths ranging from 5.5 to 21.5 III Halim eda macroloba, D,ClyOIO barlayresiana, D. Maxima, Gracliaria corl/cala var. corlicala, G. edulis, Sarcodia indica, Sarconema filiform e, Soliena rob"sla, flypnea esperi and H. "alenliae were found to be dominant and widely distributed. Hydrological data were also collected from area surveyed. The atmospheric and bottom water temperature varied from 25.0 to 36.8'C and 26.0 to 31.8'C respectively. The pH ranged from 8.3 to 8.6 and the salinity from 26.39 to 33.430/00 . The dissolved oxygen ranged from 3A2 to 6.47 mill. The phosphate content varied from 0.05 to 0. 15 I'g atm/ l, silicate from 4.00 to 12.00 I'g atmll, nitrate from 0.25 to 1.00 I'g at mil and nitrite from 1.05 to 3.99 I'g atml l

Seaweed resources off Tamil Nadu coast: Sector III. Valinokkam - Kilakkarai

Survey of seaweed resources in deep water was carried out in the area between Valinokkam and Kilakkarai during January 1989 and March,l990 respectively. In the survey from Valinokkam to Kilakkarai 33 species of marine algae were recorded of which 8 species belong to Chlorophyta, 8 to Phaeophyta and 17 to Rhodophyta. Only one species of seagrass Halophila ovalis was recorded. Among the 200 sq Icm area surveyed, vegetation occurred only in 27.5 sq.km with a total standing crop of 2962.5 tonnes (wet wt)

Seaweed resources off Tamil nadu coast, Sector - IV Kilakkarai - Rameswaram island (Dhanushkodi

Survey of the deep water area from Kilakkarai (Appa Tivu to Rameswaram Island (Dhanushkodi) was undertaken from December 1990 to January 1991 in the IV Sector survey of Deep water Seaweed Resources off Tamil Nadu coast, which formed the last phase of the survey from Rameswaram to Kanyakumari carried out during 1986-91. An area of 417 .5 sq.km. was surveyed yielding a total biomass of 18,162.5 tons (wet) seaweeds. Out of 167 stations surveyed in 13 transects, vegetation occurred only in 12 stations. Of the 29 species of marine algae recorded 8 belonged to Chlorophyta, 8 to Phaeophyta, 12 to Rhodophyta, and I to Cyanophyta, One species of seagrass Cymodocea serrulata was also recorded. Twenty species were found in estimable quantities, of which the following 8 species were abundant: Halimeda macr%ba, Spatog/ossum asperum, Zonaria crenata, Sargassum ilicijolium, Amphiroa jragilissima, Hypnea muscijormis, Botryocladia /eplOpoda and Lyngbya majuscula with a biomass of 1325, 9775, 650, 1550, 1925,300,862.5 and 1012.5 tons (wet) respectively. The species of Hypnea and Sargassum could be exploited for the manufacture of phytochemicals

Seaweed resources off Tamil Nadu coast: Kattapadu- Tiruchendure

The southern coast of Tamil Nadu from Mandapam to Kanyakumari supports luxuriant growth of economically important seaweeds and the total standing crop was estimated at 22,000 tonnes (wet). All the seaweed based industries in India mostly depend on the raw material available from this area. The seaweeds exploited from this region, particularly the agarophytes Gelidiella acerosa and Gracilaria edulis are insuiBcient to meet the raw material requirement of the industrie

Distribution of Seaweeds off Alantalai-Manapad and Vembar-Nallatanni Tivu in Tamil Nadu

The deep water areas at Alantalai--Manapad (Southern Zone) and Vembar-Nallatanni 'fivu (Northern Zone) region in Tamilnadu were surveyed during 1988 for seaweed resources employing 'SCUBA' diving technique. A total of 28 species of algae in the Southern Zone and 27 in the, Northern Zone were encountered. Majority of the seaweeds belonged to Rhodophycaae

Assessing unrealized yield potential of maize producing districts in India

The projected demand of maize production in India in 2050 is 4–5 times of current production. With the scope for area expansion being limited, there is need for enhancement of yield. This calls for identifying areas where huge unrealized yield potential exists. With a view to address the issue, the present study delineates homogeneous agro-climatic zones for maize production system in India taking district as a unit and using the factors production, viz. climate, soil, season and irrigated area under the crop. There are 146 districts in India that grow maize as a major crop. They were divided into 26 zones using multivariate cluster analysis. Study of variation in yield between districts within a zone vis-à-vis crop management practices adopted in those districts was found useful in targeting the yield gaps. These findings can have direct relevance to the maize farmers and district level administrators

Seaweed resources and distribution in deep waters from Dhanushkodi to Kanyakumari, Tamilnadu

The deepwater seaweed resources survey was carried out during 1986-1991 at the depths ranging from 5 to 22 m in Tamilnadu coast from Dhanushkodi to Kanyakumari. The vegetation of seaweeds and sea grasses occurred in all areas except Dhanushkodi - Mandapam and Manapad – Kanyakumari. A total number of 100 algae and 5 seagrasses were recorded. Among the 100 algal species recorded, 20 species belonged to Chlorophyta, 18 species to Phaeophyta, 61 species to Rhodophyta and 1 species to Cyanophyta. The total estimated standing crop (wet wt.) from 1863 sq. km. sampled area was 75374.5 tonnes consisting of 2750 tonnes of Sargassum spp., 962.5 tonnes of Gracilaria spp., 5262.5 tonnes of Hypnea spp. and 66399.5 tonnes of other seaweeds. The quantitative analysis of economically important seaweeds revealed the feasibility of commercial exploitation of Sargassum from Mandapam to Kilakkarai and Tuticorin areas, Hyphnea from Mandapam to Vembar area and Gracilaria from Vembar to Nallatanni Tivu region. Hydrological data were, also collected from the area surveyed