171 research outputs found
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
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
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 тАв 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
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
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