Realized Heritability and Genetic Gain Estimates of Larval Shell Length in the Chinese Pearl OysterPinctada martensiiat Three Different Salinities

2009 ◽  
Vol 71 (4) ◽  
pp. 302-306 ◽  
Author(s):  
Yuewen Deng ◽  
Shao Fu ◽  
Xiaodong Du ◽  
Qingheng Wang
Keyword(s):  
Shell Length ◽  
Genetic Gain ◽  
Larval Shell ◽  
Realized Heritability

Substantial Realized Gains from Mass Selection of Fusiform Rust-Free Trees in Highly Infected Stands of Slash Pine

1990 ◽  
Vol 14 (3) ◽  
pp. 143-146 ◽  
Author(s):  
G. R. Hodge ◽  
R. A. Schmidt ◽  
T. L. White
Keyword(s):  
Genetic Gain ◽  
Pinus Elliottii ◽  
Slash Pine ◽  
Mass Selection ◽  
Realized Heritability ◽  
Fusiform Rust ◽  
Rust Infection ◽  
Progeny Tests ◽  
Selection Of

Abstract Three independent slash pine (Pinus elliottii var. elliottii) populations were formed through mass selection of fusiform rust-free individuals in stands with over 90% infection. Realized gain estimates were developed by comparing offspring from 592 selections to unimproved material in 46 progeny tests, and indicate substantial genetic gain in resistance. Across all tests of the three populations, unimproved material incurred nearly the entire possible range of infection from 0 to 100%. When both parents were rust-free selections, progeny rust infection was only two-thirds of the rust infection incurred by unimproved material at all levels of rust hazard. Realized heritability is high (hr2 ≅ 0.35), and increased resistance is evident in nearly all environments. This indicates that substantial genetic gain can be made by mass selection of healthy trees in highly infected stands. South. J. Appl. For. 14(3):143-146.

Post-Larval Development of the Tellinacean Bivalves Abra Alba, Tellina Fabula and Donax Vittatus (Mollusca: Bivalvia), With Reference to the Late Larva

1986 ◽  
Vol 66 (3) ◽  
pp. 749-762 ◽  
Author(s):  
C. M. Webb
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Larval Development ◽  
Shell Length ◽  
Larval Shell ◽  
Larval Form ◽  
Scanning Electron ◽  
Morphogenetic Change

The post-larval shell and hinge development of the bivalves Abra alba (Wood), Tellina fabula Gmelin and Donax vittatus (da Costa) from the recently metamorphosed size to a juvenile size of 1·2–1·4 mm shell length has been examined using scanning electron microscopy. Early post-larval development in the stages up to 1·0–1·2 mm size can involve considerable morphogenetic change and requires careful description with photographic developmental series. The form of the pediveliger larva is present in the early post-larval shell and confirms the identity of the larvae of A. alba and T. fabula. The veliger and pediveliger larvae of A. alba are described. The similar larval form of the tellinacean bivalves is modified by differential margin growth early in post-larval development. Comparison of these bivalves with allied species reveals that the post-larvae are distinguishable at even the smallest sizes by the shell and hinge form. The metamorphic size of A. alba ranges from 0·26 to 0·31 mm, of T. fabula from 0·25 to 0·28 mm and of D. vittatus from 0·25 to 0·35 mm. The bivalve post-larvae were collected from the shallow sublittoral of Oxwich Bay, Bristol Channel, U.K., and the larvae from the overlying waters, during the years 1980–2.

Larvae of the commercial scallop, Pecten meridionalis from Tasmania, Australia

1975 ◽  
Vol 26 (1) ◽  
pp. 109 ◽  
Author(s):  
TG Dix ◽  
MJ Sjardin
Keyword(s):  
Shell Length ◽  
Larval Shell ◽  
M 31

After fertilization in the laboratory, eggs (diameter 71 �m) of Pecten meridionalis developed to straight hinge veligers with a smallest shell length of 93 �m after 3 days at 13-15� C. The larval shell developed umbones at about 160 �m, pediveligers occurred at 180 fim and larvae began crawling at metamorphosis when the shell length was 220-240 �m 31 days after fetilization. The larval shells grew almost isometrically, and length (I) and width (w) (in �m) were described closely by the G.M. regression : w = 0.9901-18.660.

scholarly journals Genetic Parameters of Common Wheat in Nepal

2016 ◽  
Vol 1 ◽  
pp. 9-13
Author(s):  
Bal Krisna Joshi ◽  
Dhruba Bahadur Thapa ◽  
Madan Raj Bhatta
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Common Wheat ◽  
Genetic Gain ◽  
Correlated Response ◽  
Realized Heritability ◽  
Improvement Program ◽  
Components Of Variance ◽  
Environmental Indices ◽  
Wheat Genotypes

Knowledge on variation within traits and their genetics are prerequisites in crop improvement program. Thus, in present paper we aimed to estimate genetic and environmental indices of common wheat genotypes. For the purpose, eight quantitative traits were measured from 30 wheat genotypes, which were in randomized complete block design with 3 replicates. Components of variance and covariance were estimated along with heritability, genetic gain, realized heritability, coheritability and correlated response. Differences between phenotypic and genotypic variances in heading days, maturity days and plant height were not large. Grain yield and plant height showed the highest phenotypic (18.189%) and genotypic (12.06%) coefficient of variances, respectively. Phenotypic covariance was higher than genotypic and environmental covariance in most of the traits. The highest heritability and realized heritability were of heading days followed by maturity days. Genetic gain for plant height was the highest. Co-heritability of 1000-grain weight with tillers number was the highest. The highest correlated response was expressed by grain yield with tillers number. This study indicates the possibility of improving wheat genotypes through selection utilizing existing variation in these traits.Journal of Nepal Agricultural Research Council Vol.1 2015 pp.9-13

scholarly journals Adaption potential of Crassostrea gigas to ocean acidification and disease caused by Vibrio harveyi

2020 ◽  
Author(s):  
Davide Nordio ◽  
Natalie Khtikian ◽  
Sean Andrews ◽  
Daniela Bertotto ◽  
Karen Leask ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Shell Length ◽  
Crassostrea Gigas ◽  
Vibrio Harveyi ◽  
Larval Shell ◽  
Phenotypic Differences ◽  
Bivalve Larvae ◽  
Survival And Development ◽  
Estimate Heritability ◽  
Slow Growing

Abstract The survival and development of bivalve larvae is adversely impacted by ocean acidification and Vibrio infection, indicating that bivalves need to simultaneously adapt to both stressors associated with anthropogenic climate change. In this study, we use a half-dial breeding design to estimate heritability (h2) for survival to Vibrio harveyi infection and larval shell length to aragonite undersaturated and normal conditions in laboratory-reared Crassostrea gigas. Phenotypic differences were observed between families for these traits with heritability estimated to be moderate for survival to V. harveyi challenge (h2 = 0.25) and low for shell length in corrosive (Ωaragonite = 0.9, h2 = 0.15) and normal conditions (Ωaragonite = 1.6, h2 = 0.15). Predicted breeding values for larval shell length are correlated between aragonite-undersaturated and normal conditions (Spearman r = 0.63, p < 0.05), indicating that larger larvae tend to do better in corrosive seawater. Aquaculture hatcheries routinely cull slow-growing larvae to reduce and synchronize time taken for larvae to metamorphose to spat, thus inadvertently applying size-related selection for larger larvae. This indirect selection in the hatchery populations provides a plausible explanation why domesticated oyster populations are less sensitive to ocean acidification.

Larval and juvenile development of the Iceland cockle Ciliatocardium ciliatum (Fabricius, 1780) (Bivalvia: Cardiidae)

2020 ◽  
Vol 324 (2) ◽  
pp. 242-251
Author(s):  
L.P. Flyachinskaya ◽  
P.A. Lezin
Keyword(s):  
Lateral Position ◽  
Larval Shell ◽  
Subtidal Zone ◽  
Larval Stages ◽  
Posterior Shoulder ◽  
Blade Shape ◽  
The Right ◽  
Lateral Structures ◽  
Juvenile Development ◽  
Concentric Structure

The paper considers the development of Ciliatocardium ciliatum from the stage of straight hinge to juvenile. In the White Sea the spawning of C. ciliatum begins at the end of June, larvae at different stages of development occur in plankton until the end of September. The earliest of the larvae found had shell lengths of 123–130 µm. The paper first examined the anatomy and structure of the larval shell of C. ciliatum. During the development, the main stages of organogenesis were described and special attention was paid to the formation of the digestive and muscular systems. The digestive system begins to function when the larva reaches a size of 170–180 µm. The digestive gland has a two-blade shape and is shifted to the right side. The foot is formed at a size of 230 µm, the gill rudiments appear when the larva reaches 270 µm. The development of the larval shell and larval hinge of the mollusc is considered in detail. The development of the larval shell of C. ciliatum is similar to the development of other family members. Throughout all the larval stages, the shell has a rounded shape with a low umbos, and the prodissoconch II has a clearly visible concentric structure. The C. ciliatum larval hinge is characterized by weak differentiation and the absence of pronounced cardinal teeth typical for other Cardiidae. However, the lateral structures of the castle – ridges and flanges – are well developed. The ligament begins to form at a size of 240–250 µm and occupies a lateral position. The settlement of the cockle takes place in September in the subtidal zone. After the metamorphosis, a large radial sculpture is formed on the dissoconch and a number of small spikes are formed at the rib of the posterior shoulder.

Genetic Gain of Soybean Breeding for Yield in Henan Summer Soybean Zone over the Last 30 Years

2016 ◽  
Vol 42 (7) ◽  
pp. 1009
Author(s):  
Zhong-Wen HUANG ◽  
Xin-Juan XU ◽  
Wei WANG ◽  
Pei-Pei MEI
Keyword(s):  
Genetic Gain ◽  
Soybean Breeding
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