scholarly journals Genotypic potentiality and selection index of ridge gourd (Luffa acutangula L.)

2020 ◽  
Vol 49 (4) ◽  
pp. 1169-1175
Author(s):  
Ayasha Ahmed ◽  
Jahangir Alam Tarafder ◽  
Mohammad Kamal Hoassain ◽  
Nazmul Alam
Keyword(s):  
Genetic Gain ◽  
Relative Efficiency ◽  
Significant Variation ◽  
Selection Index ◽  
Male Flower ◽  
Direct Selection ◽  
Flower Plant ◽  
Superior Genotypes ◽  
Selection For ◽  
Luffa Acutangula

Fifteen ridge gourd genotypes were investigated to select the superior genotypes. The overall analysis reveals that PCV was higher than GCV for all the traits. Significant variation was found among genotypes for the qualitative traits under divergence analysis. The selection index reveals that maximum genetic gain and relative efficiency over selection for yield was obtained for the index I123 based on yield/plant (g), No. of secondary branch, No. of male flower/plant characters. In the presented functions, selection index I1234 and I12345 showed highest relative efficiency over direct selection and genetic gain when all the characters were included to construct the selection index. On the basis of performance, the genotype-3023 was found to be most promising parent in order to develop a commercial ridge gourd variety.

scholarly journals Character association and genetic gain of nine agronomic traits of F1 populations in onion (Allium cepa L.)

2021 ◽  
Vol 27 ◽  
Author(s):  
A. C. Deb ◽  
R. Ara
Keyword(s):  
Genetic Gain ◽  
Agronomic Traits ◽  
Selection Index ◽  
Diallel Cross ◽  
Direct Selection ◽  
Path Coefficient ◽  
Primary Yield ◽  
Selection For ◽  
Positive Direct ◽  
Bulb Yield

F1 populations of half diallel cross were considered for this investigation. Phenotypic component of variation (s2P) was higher than genotypic (s2G), interaction ((s2I) and within error (s2w) components of variation. Trait bulb weight showed the highest values for s2P, s2G, s2I and s2w. The noticeable amount of phenotypic, genotypic, interaction and within error covariation was found in the combination of BW×BY, possibly indicating wide scope of selection for this pair of characters. Genotypic correlations were higher than the respective phenotypic correlations. This situation was also marked in the path coefficient analysis. Bulb yield/plot showed highly significant and positive correlation coefficient with other characters both at phenotypic and genotypic levels. When all the nine characters were included in an index, it exhibited the highest genetic gain as percentage. When a combination of two or more characters was studied in a function, the efficacy was higher than that of direct selection for bulb yield. The combination of five, six, seven or eight characters showed higher percentage of expected gain. Due to significantly correlated with BY and having high positive direct effect at phenotypic level characters viz., LL, BW, PH and NLs is considered as primary yield components. Again combinations of these four characters gave the commendable expected genetic gain of 330.7290% may be considered as important selection index for this material.

Opportunities for genetic improvement of lamb survival

2010 ◽  
Vol 50 (12) ◽  
pp. 1017 ◽  
Author(s):  
F. D. Brien ◽  
M. L. Hebart ◽  
D. H. Smith ◽  
J. E. Hocking Edwards ◽  
J. C. Greeff ◽  
...  
Keyword(s):  
Rectal Temperature ◽  
Selection Index ◽  
Genetic Correlations ◽  
Direct Selection ◽  
Reproduction Rate ◽  
Crown Rump Length ◽  
Selection For ◽  
Lamb Survival ◽  
Net Reproduction ◽  
Birth Time

Data on lamb survival and associated traits involving records from 15 192 lambs, 6308 dams and 284 sires from the Sheep CRC’s Information Nucleus were studied. Lamb survival to 3 days of age and to weaning was 85 and 80%, respectively, and heritability (±s.e.) was 0.014 ± 0.010 and 0.010 ± 0.010, respectively. Of the 14 traits recorded at birth, time taken for the lamb to bleat, rectal temperature and crown–rump length had the highest genetic correlations with lamb survival to weaning (–0.43 ± 0.32, 0.56 ± 0.33 and –0.38 ± 0.36, respectively). Under selection for a multi-trait objective including net reproduction rate (but not lamb survival), survival was predicted to decline genetically by 0.25 lambs weaned per 100 lambs born.year, although this was reversed to a gain of 0.20 lambs weaned per 100 lambs born.year by including the trait in the breeding objective and using 50 half-sib and 50 progeny records per selection candidate. Accuracy of selection for lamb survival was improved to 0.735 with a selection index of lamb survival to weaning, lamb ease, birth coat score, time taken to bleat, rectal temperature and crown–rump length, with the addition of 50 half-sibs and 50 progeny records per candidate. Our results suggest that unless actively incorporated into breeding objectives, lamb survival may genetically decline; however, gains are possible with direct selection using half-sib and progeny records. The addition of indirect selection criteria for lamb survival can further improve accuracy, up to 93.4%, but requires further investigation.

scholarly journals Genetic improvement of feed conversion ratio via indirect selection against lipid deposition in farmed rainbow trout (Oncorhynchus mykiss Walbaum)

2016 ◽  
Vol 116 (9) ◽  
pp. 1656-1665 ◽  
Author(s):  
Antti Kause ◽  
Anders Kiessling ◽  
Samuel A. M. Martin ◽  
Dominic Houlihan ◽  
Kari Ruohonen
Keyword(s):  
Rainbow Trout ◽  
Weight Gain ◽  
Feed Intake ◽  
Selection Index ◽  
Direct Selection ◽  
Genetic Response ◽  
Feed Conversion ◽  
Retention Efficiency ◽  
Muscle Lipid ◽  
Selection For

AbstractIn farmed fish, selective breeding for feed conversion ratio (FCR) may be possible via indirectly selecting for easily-measured indicator traits correlated with FCR. We tested the hypothesis that rainbow trout with low lipid% have genetically better FCR, and that lipid% may be genetically related to retention efficiency of macronutrients, making lipid% a useful indicator trait. A quantitative genetic analysis was used to quantify the benefit of replacing feed intake in a selection index with one of three lipid traits: body lipid%, muscle lipid% or viscera% weight of total body weight (reflecting visceral lipid). The index theory calculations showed that simultaneous selection for weight gain and against feed intake (direct selection to improve FCR) increased the expected genetic response in FCR by 1·50-fold compared with the sole selection for growth. Replacing feed intake in the selection index with body lipid%, muscle lipid% or viscera% increased genetic response in FCR by 1·29-, 1·49- and 1·02-fold, respectively, compared with the sole selection for growth. Consequently, indirect selection for weight gain and against muscle lipid% was almost as effective as direct selection for FCR. Fish with genetically low body and muscle lipid% were more efficient in turning ingested protein into protein weight gain. Both physiological and genetic mechanisms promote the hypothesis that low-lipid% fish are more efficient. These results highlight that in breeding programmes of rainbow trout, control of lipid deposition improves not only FCR but also protein-retention efficiency. This improves resource efficiency of aquaculture and reduces nutrient load to the environment.

Estimates of selection parameters associated with protein and oil content of soybean seeds (Glycine max (L.) Merr.)

1977 ◽  
Vol 28 (2) ◽  
pp. 211 ◽  
Author(s):  
R Shorter ◽  
DE Byth ◽  
VE Mungomery
Keyword(s):  
Seed Yield ◽  
Variance Component ◽  
Selection Index ◽  
Chemical Yield ◽  
Indirect Selection ◽  
Direct Selection ◽  
Yield Traits ◽  
Oil Percentage ◽  
Selection For ◽  
Location Interaction

Three crosses of soybean involving United States and other germplasm were examined in the F3 and F4 generations at two locations, one near the coast, the other on the Darling Downs. Line and line x location interaction variances within crosses for most traits were almost all significant, except for protein, oil, and protein plus oil yield where line variances were non-significant when data were combined over locations. Line variances were considerably smaller for all traits when estimated across, rather than within, locations. For protein, oil, and protein plus oil percentage, the line x location interaction variance component generally was smaller than the line variance component in two crosses, but larger in a third even though the latter cross had the largest line variance for these traits. The line x location interactions may have been related in some cases to lower protein and oil percentages of late-maturing lines in that location where cold conditions prevailed late in the season. Heritability percentages computed from F4 variance components ranged from 49 to 89% and were largest for the chemical pexentage traits within locations. Standard unit heritability percentages estimated from F3–F4 generations were lower than those computed via the variance component method, and approached zero for oil percentage, protein plus oil percentage, and the chemical yield traits in some crosses if the generations were grown in different locations. Genotypic correlations between protein percentage and seed yield ranged from –0.50 to 0.16 across crosses and were opposite in sign to those between oil percentage and seed yield. Genotypic and phenotypic correlations between protein and oil percentage were highly negative in two crosses (–0.62 to –0.96) but much less negative in the third cross (–0.24 to –0.35). Predicted genetic advance (percentage of population mean) ranged from 5.9 to 26.1% for the chemical yield traits and from 1.5 to 6.3% for protein or oil percentage. Indirect selection for chemical yield through seed yield was 90–109% as efficient as direct selection, and a selection index that combined seed yield and either protein, oil, or protein plus oil percentage generally was no more efficient than direct selection for the corresponding chemical yield trait. Indirect selection for chemical yield through chemical percentage was much less efficient than direct selection for chemical yield.

The genetic basis of growth, reproduction, and maternal environment in Romney ewes. II.* Genetic covariation between hogget characters, fertility, and maternal environment of the ewe

1972 ◽  
Vol 23 (1) ◽  
pp. 149 ◽  
Author(s):  
TS Ch'ang ◽  
AL Rae
Keyword(s):  
New Zealand ◽  
Genetic Gain ◽  
Predictive Accuracy ◽  
Genetic Correlations ◽  
Direct Selection ◽  
Maternal Environment ◽  
Subsequent Fertility ◽  
Selection For ◽  
Reproductive Characters ◽  
Selection Of

This paper is the second in a series of studies on the genetic variation and covariation in growth and reproductive characters of the New Zealand Romney sheep. The data used were obtained over a period of 11 years (1955–1965 inclusive) from a random bred experimental flock maintained at Massey University, Palmerston North, New Zealand. Phenotypic correlations were estimated between the ewe's liveweights, oestrous performance at the hogget stage (from weaning to about 14 months), and her subsequent fertility (number of lambs born per ewe) at the first lambing (2-year-old) or over several lambings. These correlations were compared from the viewpoint of accuracy in predicting, prior to first mating, a young ewe's potential fertility over one or several lambings during her own lifetime. The results suggest that for this purpose, the predictive accuracy of the hogget characters is generally low but comparable with, and in some cases, substantially greater than, that obtainable from fertility records belonging to the dam of the young ewe. Three different methods were used to estimate the genetic correlations. In general, the pattern of genetic correlations, either within the hogget characters or between them and fertility of the ewe, is predominantly one of positive values ranging from moderate size to unity. In contrast, most of the maternal genetic correlations were negative. The relative efficiency of indirect versus direct selection for genetic gain in various characters was examined under different assumptions made with regard to the maternal effect. Indirect selection, based on the measurement of hogget (yearling) liveweight or number of hogget oestruses, for genetic gain in fertility of the Romney ewe is expected, on present evidence, to be more efficient than direct selection. Of the two characters, hogget liveweight is likely to find wider application because it can be more easily measured. _________________ *Part I, Aust. J. Agric. Res., 21: 115 (1970)

scholarly journals SELECTION FOR THE DEVELOPMENT OF BLACK EYE COWPEA LINES

2018 ◽  
Vol 31 (1) ◽  
pp. 72-79 ◽  
Author(s):  
JÉSSICA DANIELE LUSTOSA DA SILVA ◽  
KAESEL JACKSON DAMASCENO-SILVA ◽  
MAURISRAEL DE MOURA ROCHA ◽  
JOSÉ ÂNGELO NOGUEIRA DE MENEZES JÚNIOR ◽  
VALDENIR QUEIROZ RIBEIRO
Keyword(s):  
Grain Yield ◽  
Block Design ◽  
Selection Index ◽  
Direct Selection ◽  
Selection Cycle ◽  
Lattice Design ◽  
Expected Gain ◽  
Selection For ◽  
New Cultivars ◽  
Selection Of

ABSTRACT Cowpea bean is a socioeconomically important legume that contribute to generate employment and income. This species presents great grain variability, and the commercial subclass black eye stands out as a very appreciated grain in Brazil and abroad, thus requiring the development of new cultivars. The objective of this work was to evaluate and select lineages of commercial black eye cowpea, based on simultaneous, and direct selection. First, 105 progenies and four controls were evaluated using the Federer's augmented block design. Seventy-seven progenies, selected from this evaluation-first selection cycle-and four controls were evaluated in three environments, using a simple 9×9 lattice design. Based on this evaluation, the second selection cycle was possible, resulting in 24 progenies. The gain by direct selection was lower than the predicted gain for grain yield in the first cycle, indicating that the selection was not effective. This result was probably due to the reduced genetic variability caused by the selection pressure. In the second cycle, the predicted and observed gains were similar, indicating that much of the expected gain was observed. The predicted and observed gains, with simultaneous selection based on the rank sum selection index, were similar in the first and second cycle. The simultaneous and direct selections resulted in genetic gains for grain yield in the two selection cycles, making it possible the selection of high grain yield lineages.

scholarly journals Differential response from selection for high calving ease vs. low birth weight in American Simmental beef cattle

2020 ◽  
Vol 98 (7) ◽  
Author(s):  
Hamad M Saad ◽  
Milton G Thomas ◽  
Scott E Speidel ◽  
Richard K Peel ◽  
W Marshall Frasier ◽  
...  
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Selection Index ◽  
Differential Response ◽  
Direct Selection ◽  
Weaning Weight ◽  
Calving Ease ◽  
Selection For ◽  
Maternal Grandsire ◽  
Genetic Trends

Abstract Data on calving ease (CE) and birth, weaning weight (WW), and yearling weight (YW) were obtained from the American Simmental Association (ASA) and included pedigree and performance information on 11,640,735 animals. Our objective was to quantify differential response from selection for high CE vs. low birth weight (LBW) in first-calf Simmental heifers. We hypothesized that direct selection for CE should be used as the primary approach to reduce dystocia and mitigate losses in growth-related traits. WW and YW were adjusted to 205 and 365 d of age, respectively. Sire and maternal grandsire (co)variance components for CE, birth weight (BW), and 205-d weaning weight (205-d WW), and sire covariance components for 160-d postweaning gain (160-d gain) were estimated using a sire-maternal grandsire model. Direct and maternal expected progeny differences (EPD) for CE, BW, and 205-d WW and direct EPD for 160-d gain and 365-d yearling weight (365-d YW) for first-calf Simmental heifers population (465,710 animals) were estimated using a threshold-linear multivariate maternal animal model. This population was used to estimate genetic trends and as a selection pool (control) for various selection scenarios. Selection scenarios were high CE (HCE), LBW, the all-purpose selection index (API = −1.8 BW + 1.3 CE + 0.10 WW + 0.20 YW) of the ASA and its two derived subindices: (API1 = 1.3 CE + 0.20 YW) and (API2 = −1.8 BW + 0.20 YW), and lastly Dickerson’s selection index (DSI = −3.2 BW + YW). Data for each selection scenario were created by selecting sires with EPD greater than or equal to the average along with the top 75% of dams. Comparison between selection scenarios involved evaluating the direct and maternal genetic trends from these scenarios. Direct heritabilities for CE, BW, 205-d WW, 160-d gain, and 365-d YW of Simmental cattle were 0.23, 0.52, 0.28, 0.21, and 0.33, respectively. The single trait, HCE, selection scenario, as opposed to LBW, increased the intercept for CE by 57.7% and the slopes (P < 0.001) for BW, 205-d WW, 160-d gain, and 365-d YW by 27.9%, 37.5%, 16%, and 28%, respectively. Comparisons of various selection scenarios revealed that the CE-based selection scenarios (HCE, API, and API1) had a greater response for CE and growth traits.

Breeding white clover for increased ability to compete with associated grasses

2003 ◽  
Vol 140 (3) ◽  
pp. 255-266 ◽  
Author(s):  
P. ANNICCHIARICO
Keyword(s):  
Relative Efficiency ◽  
Competitive Ability ◽  
Clonal Selection ◽  
Selection Index ◽  
Size Variation ◽  
Leaf Size ◽  
Indirect Selection ◽  
Italian Ryegrass ◽  
Direct Selection ◽  
Selection Procedures

Greater white clover (Trifolium repens L.) competitive ability can increase the forage quantity and quality of clover-grass mixed stand (MS) cropping. The present work assessed the relationship of clover competitive ability with morphophysiological traits, and the efficiency of direct and indirect selection procedures for increasing clover dry matter (DM) yield in MS. Some 165 large-leaved clover genotypes representative of Italian Ladino germplasm and 13 clover genotypes from an elite small-leaved population were clonally evaluated for one year in pure stand (PS) and in MS environment with Italian ryegrass (Lolium multiflorum Lam.) and tall fescue (Festuca arundinacea Schreb.) that reproduced the level of interspecific interference met by the clover over a multi-year crop cycle. Results for all genotypes and their subsets indicated that the level of leaf size variation among tested genotypes can affect the results. Wider variation decreased the relative importance of clover genotype×evaluation environment interaction, because competitive ability was mainly correlated with traits (longer petiole; larger leaflet) contributing to scale foraging in MS and yielding ability in PS. Competitive ability tended to be more closely associated with other traits (high stolon density; plasticity of petiole elongation) contributing to foraging ability, i.e. the ability to make fine-scale exploitation of light and nutrients in MS, within germplasm of similar leaf size. Leaf size variation also affected the relative efficiency of selection procedures estimated from expected responses to clonal selection. Results for all entries indicated direct selection in MS as 23% more efficient than selection in PS based on a selection index including three traits associated with competitive ability (petiole length; stolon density; leaflet size) which, in turn, was predicted to be 16% more effective than selection in PS based on DM yield. The advantage in relative efficiency of direct selection was almost doubled when considering only large-leaved germplasm. In a second experiment, evaluating 16 clover half-sib progenies of elite large-leaved parents for 2 years in PS and in MS with Italian ryegrass, tall fescue and cocksfoot (Dactylis glomerata L.), direct selection was estimated to be over three-fold and 68% more effective than indirect selection in PS based on DM yield and the selection index, respectively, based on expected responses to genotypic selection. The selection index may improve the efficiency of preliminary, PS-based clonal selection. Further evaluation of elite genotypes and/or their polycross progenies in MS is recommended for final selection.

scholarly journals Effects of Incorporating Dry Matter Intake and Residual Feed Intake into a Selection Index for Dairy Cattle Using Deterministic Modeling

Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1157
Author(s):  
Kerry Houlahan ◽  
Flavio S. Schenkel ◽  
Dagnachew Hailemariam ◽  
Jan Lassen ◽  
Morten Kargo ◽  
...  
Keyword(s):  
Feed Intake ◽  
Feed Efficiency ◽  
Selection Pressure ◽  
Dry Matter ◽  
Selection Index ◽  
Residual Feed Intake ◽  
Dry Matter Intake ◽  
Direct Selection ◽  
Response To Selection ◽  
Selection For

The inclusion of feed efficiency in the breeding goal for dairy cattle has been discussed for many years. The effects of incorporating feed efficiency into a selection index were assessed by indirect selection (dry matter intake) and direct selection (residual feed intake) using deterministic modeling. Both traits were investigated in three ways: (1) restricting the trait genetic gain to zero, (2) applying negative selection pressure, and (3) applying positive selection pressure. Changes in response to selection from economic and genetic gain perspectives were used to evaluate the impact of including feed efficiency with direct or indirect selection in an index. Improving feed efficiency through direct selection on residual feed intake was the best scenario analyzed, with the highest overall economic response including favorable responses to selection for production and feed efficiency. Over time, the response to selection is cumulative, with the potential for animals to reduce consumption by 0.16 kg to 2.7 kg of dry matter per day while maintaining production. As the selection pressure increased on residual feed intake, the response to selection for production, health, and fertility traits and body condition score became increasingly less favorable. This work provides insight into the potential long-term effects of selecting for feed efficiency as residual feed intake.

Sign in / Sign up

Export Citation Format

Share Document