A characterization of fuzzy trees

In this paper some properties of fuzzy bridges are studied.A characterization of fuzzy trees is obtained using these concepts.

Convex extendable trees

The concept of convex extendability is introduced to answer the problem of finding the smallest distance convex simple graph containing a given tree. A problem of similar type with respect to minimal path convexity is also discussed.

Studies on the reproductive physiology and breeding biology of the cultivable species of grouper Epinephelus tauvina (Forsskal)

School of Industrial Fisheries,Cochin University of Science and Technology

Bionomics, cryopreservation of gametes and captive breeding behaviour of threatened hillstream cyprinid, garra surendranathanii(shaji, arun & easa, 1996)

Garra surendranathanii is a hill stream cyprinid endemic to Kerala. According to IUCN based classification, G. surendranathanii is grouped under the threatened category. This endemic fish is having highly restricted and fragmented distribution and reported only from 5 river systems viz. Chalakudy, Periyar, Pamba, Achenkoil and Bharathapuzha. Categorization of this fish as a potential ornamental candidate can invariably add more pressure on the threat status of this particular species. Hence, this species is considered as one which requires foremost attention for conservation. Hitherto, no infomiation is available on the bionomics, resource characteristics and any conservation attempts of G. surendranathanii. Studies on detailed life history traits and development of captive breeding technique are indispensable for successful fishery management.The present study was undertaken with the following obj ectives: To study the Length-weight relationship and condition factor to ascertain the relationship between length and weight and general wellbeing ofthe fish To study the age and growth to understand the age composition of the exploited stock, age at first maturation and life span of the species. To study the reproductive biology of G. surendranathanii to gain insights in the process of gametogenesis, spawning, sex ratio, fecundity and other related aspects which are essential for developing captive breeding technology of this species. To develop captive breeding technology and cryopreservation ofgametes of G. surendranathanii for conservation

Studies on genetic polymorphism in Santalum Album L.

Loss of natural sandal populations due to illicit felling, forest encroachment and spike disease have an adverse effect on genetic diversity of the species. To initiate any genetic improvement programme in sandal, a precise understanding of the population genetic diversity structure is essential. The concern over the loss of genetic variability in sandal is particularly critical, as there is hardly any information regarding the diversity status of the natural populations. Identifying fast growing, disease resistant, oil rich sandal trees through breeding and their mass multiplication for afforestation are the best method for ensuring sustainable supply of superior sandalwood. The healthy sandal trees existing in heavily spike diseased area can be used as a promising starting point for any such breeding programme (Venkatesh, 1978). So far, no genetic information is available regarding the resistant nature of spike disease evaded trees left in heavily infected patches. The high rate of depletion of the superior trees in South Indian sandal reserves due to illegal felling and spike disease has necessitated an urgent need for conservation of the surviving trees.Widespread occurrence of spike disease in Marayoor forest reserve was reported in 1981 (Ghosh and Balasundaran, 1995). Because of the high density of trees and varying intensity of spike disease, Marayoor sandal population was found to be ideal for experimental studies in sandal (Ghosh et al., 1985). Fifteen trees of reserve 51 of Marayoor range had been selected as candidate plus trees for growth and spike disease evasion . These trees have been selected for mass multiplication through tissue culture technique.