Genetic variability and frequency distribution studies in F2 population involving traditional variety mappillai samba

The parasitism of trout in Algonquin Park, Ont., was studied during the spring and summer of 1939 to determine the distribution and abundance of parasites in the several species of trout. The sampling included 34 lakes from five different river drainages.A list of the parasites follows with the hosts indicated by the letters, C for Cristivomer namaycush Wahlbaum, S for Salvelinus fontinalis Linnaeus, and F for Salmo fario Linnaeus. Protozoa (cysts in kidneys),—CSF; trematodes: Crepidostomum farionis,—CS, Azygia angusticauda,—C, Clinostomum complanatum,—S, Neascus sp. (larvae),—S; cestodes: Diphyllobothrium sp. (larvae),—C, Eubothrium salvelini,—CS, Proteocephalus ambloplitis (larvae),—CS, Proteocephalus parallactics,—CSF, Proteocephalus pusillus,—C; nematodes: Cystidicola stigmatura,—CS, Philonema sp.,—C, unidentified larval nematodes,—CS, acanthocephala: Leptorhynchoides thecatus,—C; copepoda: Salmincola edwardsii,—S, Salmincola siscowet,—C.Two of the tapeworms, the two copepods, and the protozoan kidney cysts were generally distributed. The other parasites showed local differences in abundance. Frequency distribution studies of several of the parasite populations indicated that the parasites are not distributed randomly to the hosts.

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Genetic Variability, Correlation and Path Coefficient Analysis in F2 Segregating Population in Tomato (Solanum lycopersicum L.)

Madras Agricultural Journal ◽

10.29321/maj.01.000403 ◽

2017 ◽

Vol 104 (.1-.4) ◽

Author(s):

Gopinath P ◽

◽

Irene Vethamoni P

Keyword(s):

Genetic Variability ◽

Fruit Weight ◽

Fruit Yield ◽

Direct Selection ◽

Path Coefficient ◽

Genetic Advance ◽

Solanum Lycopersicum L ◽

F2 Population ◽

Positive Direct ◽

Pericarp Thickness

Genetic variability, heritability and genetic advance for fifteen yield contributing traits were studied in F2 population obtained from the cross of Arka Vikas × EC 519809. The study indicated that existence of considerable amount of genetic variability for all the characters studied. The characters viz., fruit yield per plant, number of fruits per plant, number of primary branches, total phenol and pericarp thickness exhibited higher values of genotypic and phenotypic coefficient of variation. Whereas, fruit yield per plant, individual fruit weight, pericarp thickness and number of primary branches per plant exhibited high estimates of heritability and genetic advance for yield per plant and average fruit weight. These characters can be effectively improved through selection. Correlation indicated that yield was significantly and positively associated with plant height, number of flowers per cluster, percent fruit set, fruit length, fruit diameter, individual fruit weight and number of fruits per plant. Number of fruits per cluster and number of fruits per plant showed the highest positive direct effect on fruit yield per plant. Direct selection may be executed considering these traits as the main selection criteria to reduce indirect effect of other characters during development of high yielding tomato variety.

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Frequency distribution studies of epipelic diatoms along an intertidal shore

Helgoländer Meeresuntersuchungen ◽

10.1007/bf02364696 ◽

1987 ◽

Vol 41 (2) ◽

pp. 139-148 ◽

Cited By ~ 6

Author(s):

Deborah R. Oppenheim

Keyword(s):

Frequency Distribution ◽

Epipelic Diatoms ◽

Distribution Studies

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Genetic variability study in F2 population of tetraploid dicoccum wheat crosses

Journal of Applied and Natural Science ◽

10.31018/jans.v10i2.1777 ◽

2018 ◽

Vol 10 (2) ◽

pp. 773-778

Author(s):

Channappagouda Patil ◽

Deepak Koujalagi

Keyword(s):

Genetic Variability ◽

Grain Yield ◽

Plant Height ◽

Coefficient Of Variation ◽

Tiller Number ◽

Genetic Advance ◽

F2 Population ◽

Spike Number ◽

The Cross ◽

High Degree

The aim of the present investigation was to estimate the genetic variability parameters in Wheat (Triticum dicoccum) F2 population of the cross DDK1025 X ML-1. The traits involved in study were grain yield, threshability, rachis percent and other yield contributing traits such as tiller number, number of grains per spike, number of spikelet’s per spike, etc. and the genetic variability parameters estimated are mean, range, Phenotypic coefficient of variation (PCV), Genotypic coefficient of variation (GCV), heritability and genetic advance over mean. The results obtained from the study reveals higher mean and wider range for all the traits especially for plant height, tiller number, spikelets per spike, number of grains per spikelet, spike length, grain yield per plant, threshability and rachis. High degree of PCV with moderate GCV was observed for the traits like number of tiller per plant (20.96 PCV and 15.96 GCV), number of grains per spike (21.92 PCV and 18.79 GCV), rachis % (22.5 PCV and 19.10 GCV) and grain yield per plant (20.07 PCV and 18.10) . Heritability and genetic advance was recorded to high for all the traits in both the populations. On the basis of an overall consideration of the genetic variability parameters it may be concluded that F2 population of the cross, DDK-1025 x ML-1 have the potential source for improving the yield and its associated traits and also offering some scope in altering the plant height.

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