Reproductive cycle and biochemical changes in the Gonads of the freshwater crab, Barytelphusa cunicularis (Westwood, 1836)

The annual breeding cycle of the crab, Barytelphusa cunicularis, was determined by measuring monthly the size of the gpnad relative to the size of the animal. The peak of gonad size appeared in rainy season (June to September) showing the maximum breeding activity during these months. Histological observations of the monthly gonads revealed that the ripening of the gonads started during March and extended upto May. By June the gonads of most of the individuals attained full maturity and spawning began. Spawning terminated by the end of September and the gonads entered a quiescent period

Reproduction in edible bivalve shellfishes of Ratnagiri Coast

Clams, oysters and mussels are regularly fished and marketed at different places in Ratnagiri district throughout year, rarely in peak of monsoon. The annual reproductive cycles of three species of edible clams Paphia laterisulca, Katelysia opima and Meretrix meretrix, the oysters Saccostrea cucullata and C. grypholdes and the green mussel Perna virldis of the Ratnagiri coast have been studied. Maximum gonad index occurs during June-August and November-February in P. laterisulca, June-September and January-February In K. opima and February-August In M. meretrix. The histological studies revealed spawning m P. laterisulca during mid September-Match with two peaks • once in October-November and another In February-March. Spawning in K. opima occurs during October-November and March-April. M. meretrix spawns only during October-November. S. cucullata spawns during October-January, and C, grypholdes during October-November. P. virldis spawns during late July-early September. The difference In such spawning periods of these shellfishes have be°n attributed to the change* In salinities in the respective habitats with the secondary cffecta of temperature on the gonads- The results are discussed in the light of species adjustment to the fluctuating environment and biochemical-phyiiology

Neuroendocrine regulation in Lamellibranch molluscs

Gametogenesis and spawning in lamellibranch molluscs may be controlled by either exogenous or endogenous factors. Though the factors like salinity or temperature in such studies have been widely elaborated by various workers, the endogenous regulation stilt remains in its infancy. Our experimental studies, based on the classic histological staining of the neurosecretory material, have revealed neurosecretory cells in the central ganglia of lamellibranch molluscs. The tinctorial properties of these cells may vary from species to species. The pyriform (pear-shaped) neurosecretory cells from cerebral ganglia revealed such endogenous regulation system affecting the release of sex products. There exists four successive stages in the passage of neurosecretory product within the sell body- This has been extensively worked out in case of Perna from Ratnagiri coast. The data have been correlated with the gonad maturation stages and spawning

Toxicity evaluation of the holothrian Holothuria (mertensiothuria) leucospilota (Brandt) and The effect of toxin on the prawn Caridina rajadhari

The evaluation of lethal and sublethal concentrations is an important step for further studies on behavioural and physiological changes in the animal. In the present investigation toxicity eveduation was done using computational procedure for critical analysis of the regression line relating probits and log dose. In the present study five size groups of the prawn Caridina rajadhari namely juveniles, immature females, immature males, mature females and mature males were used and the LC51, values were calculated upto 96 hrs. It was observed that the percent mortality of the five size groups increased progessively upto 96 hours in all concentrations of holothurian toxin and the LC^j values decreased with increasing exposure period. The size and sex dependent toxicity indicated that LCj,, values followed by immature male, immature female, mature male and mature female. It was observed that males were found to be more tolerant than females in both immature aand mature stages. It was also observed that mature females were most susceptible and the juveniles are more tolerant among the test animals

Performance of introduced confectionery lines for yield and quality characteristics at ICRISAT Center, India

About a third of the world's groundnut production is consumed in the form of edible nuts. Large-seeded groundnuts are preferred for direct consumption. Development of large-seeded varieties with improved seed quality characteristics is an important breeding activity at ICRISAT Center. India and at North Carolina State University (NCSU), Raleigh, USA. We obtained 65 largeseeded advanced breeding/germplasm lines from NCSU to broaden the genetic base.............

Inheritance of period from seedling emergence to first flowering in peanut (Arachis Hypogaeal)

F 1 progenies peanut (Arachis hypogaeal. L.) from a 6 x diallel, including reciprocals and their parents, were evaluated for the number of days seedlings emergence to first flower appearance during the 1981 and 1982 rainy seasons at ICRISAT Centre, Patancheru, India. Genetic analysis indicated the predominant role of additive genetic variance in the expression of this character. Genotype 91176 had the best general combining ability for early flowering and has the potential for use in breeding programs.Variety M 13 had the best general combining ability for late flowerin

Genetic Analysis of Trichome Characters Associated with Resistance To Jassid (Empoasca kerri Pruthi) in Peanut

F1 progenies resulting from a 10 x 10 diallel cross including reciprocals, in peanut (Arachis hypogaea L. ) cultivars of different susceptibility to the jassid, Empoasca kerri Pruthi, were studied to determine the inheritance of trichomes on the adaxial surface of the leaf, leaf midrib, and petiole, and their association with resistance to E. kerri. Genotypes or crosses with long trichomes on the leaves and petioles showed a high level of resistance to jassids (leafhoppers) as evidenced by a very low percentage of yellowed foliage (hopper bum). Nonadditive genetic variance was predominantly observed for all trichome characters. However, additive genetic variance was also important for the presence of long trichomes on the midrib and petioles and for jassid damage. NC Ac 2230, a jassid resistant line, is the best parent to use in a breeding program because of its stable resistance and high general combining ability for the presence of trichomes

Relationship of Seed Mass to Oil and Protein Contents in Peanut (Arachis hypogaea L.)

Seed mass, oil and protein contents are important quality traits in peanut (Arachis hypogaea L.). Sixty-four genotypes were grown for four seasons to study genetic variation and character association between these three traits. Graded seed samples of 33 genotypes were further studied for possible variation within genotype among grades for oil and protein contents. No significant association of seed mass with percent oil or protein contents was observed among the 64 genotypes. However, oil and protein contents were significantly negatively associated. Oil content variation within a genotype showed a significant linear increase as the seed mass increased in the graded samples, but no such relationship was observed with protein content. Genotypes with desirable traits for confectionery and/or oil types were identified and may be used for germplasm enhancement