Selection for crimp frequency in the wool of Merino sheep. 1. Direct response to selection

1967 ◽  
Vol 7 (29) ◽  
pp. 552 ◽  
Author(s):  
GE Robards ◽  
WA Pattie
Keyword(s):  
First Generation ◽  
Agricultural Research ◽  
Steady Increase ◽  
Research Station ◽  
Direct Response ◽  
Satisfactory Explanation ◽  
Gene Frequencies ◽  
Selection For ◽  
Contrast Response ◽  
Large Response

Two selection flocks consisting of 100 ewes mated to five rams were established at the Agricultural Research Station, Trangie, in 1950. One flock was selected for high crimp frequency (Crimps Plus), and the other for low crimp frequency (Crimps Minus). Responses in these flocks were measured against a randomly selected control flock maintained in the same environment and with the same management. The Crimps Plus flock showed a steady increase in crimp frequency with realized heritabilities of 0.46 � 0.14 for ewes and 0.38 � 0.15 for rams, calculated over five generations of selection. In contrast, response in the Crimps Minus flock was not linear as there was a large response in the first generation but very little after that. Dam-offspring heritabilities calculated for sheep entering the flocks after the first generation were 0.40 � 0.14 for the Crimps Minus flock and 0.47 � 0.15 for the Crimps Plus flock. It is suggested that prior selection in the base population may have resulted in unequal gene frequencies, and hence the reduction of response in the Crimps Minus flock. No satisfactory explanation could be given for the large response to the first generation of selection in this flock.

scholarly journals INTERACTION BETWEEN NATURAL SELECTION FOR HETEROZYGOTES AND DIRECTIONAL SELECTION

Genetics ◽  
1974 ◽  
Vol 76 (1) ◽  
pp. 163-168
Author(s):  
Margrith Wehrli Verghese
Keyword(s):  
Natural Selection ◽  
First Generation ◽  
Genetic Variance ◽  
Selection Response ◽  
Directional Selection ◽  
Simple Function ◽  
Small Populations ◽  
Gene Frequencies ◽  
Selection For

ABSTRACT When directional selection for an additively inherited trait is opposed by natural selection favoring heterozygous genotypes a selection plateau may be reached where genetic variance is present. The amount of response when this plateau is reached is a simple function of the selection response in the first generation and the intensity of natural selection. When selection is practiced in small populations, the sizes of the initial equilibrium gene frequencies are at least as important as the intensity of natural selection in determining the probability of fixing desirable alleles.

Skin folds and Merino breeding. 8. Fertility of individual rams in flocks selected for high and low skin fold

1969 ◽  
Vol 9 (37) ◽  
pp. 147 ◽  
Author(s):  
BJ McGuirk
Keyword(s):  
Artificial Insemination ◽  
Agricultural Research ◽  
New South ◽  
New South Wales ◽  
Research Station ◽  
South Wales ◽  
Skin Fold ◽  
Single Character ◽  
Lower Fertility ◽  
Selection For

Single character selection flocks-Folds Plus (selection for high fold score) and Folds Minus (selection for low fold score) were established in 1951 from a Peppin Merino flock at Trangie Agricultural Research Station, New South Wales. For the period 1951 to 1966, 25 per cent of rams selected for the Folds Plus flock were rejected following semen examination before joining, compared to only three per cent of Folds Minus rams (P<0.05). The fertility of individual rams in the two flocks has been estimated from the lambing performance of the ewes to which they were mated in the period 1951 to 1963. Averaged over the twelve joinings, a higher proportion of ewes mated to Folds Minus rams lambed following both artificial insemination (53 v. 45 per cent) and paddock joinings (57 v. 47 per cent). The lower fertility of the Folds Plus rams was not due to a higher proportion of completely infertile rams.

Reproductive performance of ewe lambs: genetic correlation with weaning weight and subsequent reproductive performance

1976 ◽  
Vol 16 (80) ◽  
pp. 321 ◽  
Author(s):  
R Barlow ◽  
CJ Hodges
Keyword(s):  
Genetic Correlation ◽  
Reproductive Performance ◽  
Agricultural Research ◽  
Reproductive Rate ◽  
Research Station ◽  
Weaning Weight ◽  
Net Reproductive Rate ◽  
Ewe Lambs ◽  
Ewe Lamb ◽  
Selection For

The reproductive performance of Merino ewe lambs was examined in flocks with different selection histories for growth to weaning and net reproductive rate. These ewes were drawn from selection flocks maintained at the Agricultural Research Station, Trangie. There was evidence of a positive genetic correlation between weaning weight and reproductive performance of ewe lambs. Selection for weaning weight had a significant effect on the percentage of ewes lambing (P < 0.05). This appeared to be a function of a higher level of fertility (P <0.05) and a higher proportion of ewes mating (n.s.). The proportion of ewes apparently in oestrus during a 39 day teasing period, prior to joining, was significantly influenced by selection for weaning weight (P < 0.05). Simultaneous selection for increased net reproductive rate, weaning weight and clean fleece weight did not result in higher ewe lamb performance than that achieved by selection for increased weaning weight alone. No conclusion could be drawn from these data about the correlation between net reproductive rate and reproductive performance of ewe lambs.

Effect of intercrops on growth and yield of turmeric (Curcuma longa L.)

2017 ◽  
Vol 26 (1) ◽  
pp. 51
Author(s):  
R Chitra, P Hemalatha
Keyword(s):  
Short Duration ◽  
Agricultural Research ◽  
Curcuma Longa ◽  
Growth And Yield ◽  
Research Station ◽  
Initial Growth ◽  
Agricultural Research Station

The initial growth of turmeric is rather slow and takes about 4-5 months to cover the inter space. Therefore, the available space between the rows of turmeric could be effectively utilized by growing short duration crops like, vegetables, cereals etc. Hence, it is worthwhile to explore the possibilities of growing compatible crops with turmeric. With this background the experiment on effect of intercrops on growth and yield of turmeric was conducted at Agricultural Research Station, Bhavanisagar. Among the different intercrops, turmeric with cowpea recorded the maximum fresh rhizome yield per hectare (30.78 t ha-1) while turmeric + bhendi registered the maximum B:C ratio (2.68:1). Monocropping of turmeric recorded the lowest B:C ratio (1.67:1) among all the treatments.  

ROLE OF CONSERVATION AGRICULTURE IN IMPROVING PRODUCTION WATER AND NITROGEN EFFICIENCY OF WHEAT UNDER RAINFED CONDITIONS

2020 ◽  
Vol 51 (4) ◽  
pp. 1139-1148
Author(s):  
Othman & et al.
Keyword(s):  
Crop Rotation ◽  
Nitrogen Use Efficiency ◽  
Agricultural Research ◽  
Research Work ◽  
Conservation Agriculture ◽  
Nitrogen Efficiency ◽  
Research Station ◽  
Wheat Varieties ◽  
Nitrogen Use ◽  
Use Efficiency

The research work was conducted in Izra’a Research station, which affiliated to the General Commission for Scientific Agricultural Research (GCSAR), during the growing seasons (2016 – 2017; 2017 – 2018), in order to evaluate the response of two durum wheat verities (Douma3 and Cham5) and two bread wheat varieties (Douma4 and Cham6) to Conservation Agriculture (CA) as a full package compared with Conventional Tillage system (CT) under rainfed condition using lentils (Variety Edleb3) in the applied crop rotation. The experiment was laid according to split-split RCBD with three replications. The average of biological yield, grain yield,  rainwater use efficiency and nitrogen use efficiency was significantly higher during the first growing season, under conservation agriculture in the presence of crop rotation, in the variety Douma3 (7466 kg. ha-1, and 4162kg. ha-1, 19.006 kg ha-1 mm-1,  39.62 kg N m-2respectively). The two varieties Douma3 and Cham6 are considered more responsive to conservation agriculture system in the southern region of Syria, because they recorded the highest grain yields (2561, 2385 kg ha-1 respectively) compared with the other studied varieties (Cham5 and Douma4) (1951 and 1724 kg ha-1 respectively). They also exhibited the highest values of both rainwater and nitrogen use efficiency.

Influence of sowing dates on the incidence of powdery mildew of chilli

2017 ◽  
Vol 4 (2) ◽  
Author(s):  
SUDHEENDRA A. ASHTAPUTRE
Keyword(s):  
Powdery Mildew ◽  
Field Experiment ◽  
Disease Severity ◽  
Agricultural Research ◽  
Time Interval ◽  
Research Station ◽  
Inoculum Potential ◽  
Weather Factors ◽  
Agricultural Research Station ◽  
Sowing Dates

A field experiment was conducted during kharif, 2005 at Agricultural Research station, Devihosur, Haveri, Karnataka to assess the progress of powdery mildew at different time interval of sowing dates. Totally 20 different dates of sowings were imposed in the experiment at an interval of 10 days. The crop sown on last week of May to mid of June recorded minimum disease severity compared to rest of the date of sowings. This clearly indicated that crop sown during this period suffers less, which may be due to low inoculum potential, whereas late sown crop suffers more because of the readily available inoculum in the early sown crops. Low disease severity in last week of May to mid of June sowing may be attributed to the non-congenial weather factors for the development of the disease.

Selection for components of efficient lean growth rate in pigs 2. Selection pressure applied and direct responses in a Landrace herd

1994 ◽  
Vol 59 (2) ◽  
pp. 263-269 ◽  
Author(s):  
N. D. Cameron ◽  
M. K. Curran
Keyword(s):  
Growth Rate ◽  
Genetic Correlations ◽  
Correlated Response ◽  
Selection Line ◽  
Control Line ◽  
Direct Response ◽  
Lean Growth ◽  
Ad Libitum ◽  
Selection For ◽  
Ad Libitum Feeding

AbstractResponses to divergent selection for lean growth rate with ad-libitum feeding (LGA), for lean food conversion (LFC) and for daily food intake (DFI) in Landrace pigs were studied. Selection was practised for four generations with a generation interval ofl year. A total of 2642 pigs were performance tested in the high, low and control lines, with an average of 37 boars and 39 gilts performance tested per selection line in each generation. The average within-line inbreeding coefficient at generation four was equal to 0·04. There was one control line for the DFI and LFC selection groups and another control line for the LGA selection group. Animals were performance tested in individual pens with mean starting and finishing weights of 30 kg and 85 kg respectively with ad-libitum feeding. The selection criteria had phenotypic s.d. of 32, 29 and 274 units, for LGA, LFC and DFI, respectively, and results are presented in phenotypic s.d.Cumulative selection differentials (CSD) were 5·1, 4·5 and 5·5 phenotypic s.d. for LGA, LFC and DFI, respectively. Direct responses to selection were 1·4,1·1 and 0·9 (s.e. 0·20) for LGA, LFC and DFI. In each of the three selection groups, the CSD and direct responses to selection were symmetric about the control lines. The correlated response in LFC (1·1, s.e. 0·19) with selection on LGA was equal to the direct response in LFC. In contrast, the direct response in LGA was greater than the correlated response (0·7, s.e. 0·18) with selection on LFC. There was a negative correlated response in DFI (-0·6, s.e. 0·18) with selection on LFC, but the response with selection on LGA was not significant (0·2, s.e. 0·16).Heritabilities for LGA, LFC and DFI ivere 0·25, 0·25 and 0·18 (s.e. 0·03), when estimated by residual maximum likelihood, with common environmental effects of 0·12 (s.e. 0·02). Genetic correlations for LFC with LGA and DFI were respectively positive (0·87, s.e. 0·02) and negative (-0·36, s.e. 0·09), while the genetic correlation between DFI and LGA was not statistically different from zero, 0·13 (s.e. 0·10). Selection on components of efficient lean growth has identified LGA as an effective selection objective for improving both LGA and LFC, without a reduction in DFI.

Selection for rate and efficiency of lean gain in Hereford cattle 1. Selection pressure applied and direct responses

1990 ◽  
Vol 51 (1) ◽  
pp. 23-34 ◽  
Author(s):  
R. A. Mrode ◽  
C. Smith ◽  
R. Thompson
Keyword(s):  
Genetic Parameters ◽  
Control Line ◽  
Correlated Responses ◽  
Direct Response ◽  
Lean Growth ◽  
Hereford Cattle ◽  
Frozen Semen ◽  
Phenotypic Standard Deviation ◽  
Selection For ◽  
Selection Of

ABSTRACTSelection of bulls for rate and efficiency of lean gain was studied in a herd of Hereford cattle. There were two selection lines, one selected for lean growth rate (LGR) from birth to 400 days and the other for lean food conversion ratio (LFCR) from 200 to 400 days of age, for a period of 8 years. A control line bred by frozen semen from foundation bulls was also maintained. Generation interval was about 2·4 years and average male selection differentials, per generation were 1·2 and — 1·1 phenotypic standard deviation units for LGR and LFCR respectively.Genetic parameters and responses to selection were estimated from the deviation of the selected lines from a control line and by restricted maximum likelihood (REML) techniques on the same material. Realized heritabilities were 0·40 (s.e. 0·12) for LGR and 0·40 (s.e. 0·13) for LFCR using the control line. Corresponding estimates from REML were 0·42 (s.e. 0·10) and 0·37 (s.e. 0·14). The estimate of the genetic correlation between LGR and LFCR was about — 0·69 (s.e. 0·12) using REML.The estimates of direct annual genetic change using deviations from the control were 3·6 (s.e. 1·3) g/day for LGR and — 0·14 (s.e. 0·07) kg food per kg lean gain for LFCR. Corrsponding estimates from REML were similar but more precisely estimated. The correlated responses for LFCR in the LGR line was higher than the direct response for LFCR.

Biofortification of Zn and Fe in Chickpea through Agronomic Intervention in Medium Black Soils of Karnataka

2020 ◽  
Author(s):  
Pandit S. Rathod ◽  
D.H. Patil ◽  
S.B. Bellad ◽  
Rachappa V. Haveri
Keyword(s):  
Seed Treatment ◽  
Dietary Diversity ◽  
Agricultural Research ◽  
Research Station ◽  
Nutritional Security ◽  
Foliar Fertilization ◽  
Pooled Data ◽  
Net Returns ◽  
Better Than ◽  
Plot Design

Background: Bio-fortification, the process of integrating nutrients into food crops, provides a sustainable and economic way of increasing the density of micronutrients in important staple crops. Agronomic bio-fortification is the easiest, practicable and fastest way for bio-fortification of pulse grains with Fe, Zn, or other desirable micronutrients. Increasing micronutrient rich foods and improving dietary diversity will substantially reduce micronutrient disorders.Methods: A field experiment was conducted during the post rainy seasons of 2015, 2016 and 2017 at Zonal Agricultural Research Station, Kalaburagi, University of Agricultural Sciences, Raichur (Karnataka) to know the effect of soil and foliar fertilization of Zn and Fe on chickpea genotypes. Two genotypes (Annigeri 1 and JG 11) and six fertilization treatments (Control, 0.5% Zn, 0.1% Fe, Zn + Fe, seed treatment with 2 g Zn kg-1 seeds and soil application of Zn) were tested in medium black soils in split plot design with three replications.Result: The pooled data of three seasons indicated that the genotype JG 11, performed better than Annigeri 1 in terms of seed yield (1309 kgha-1), net returns (₹ 31634ha-1) and B: C ratio (2.52). On biofortification of Zn and Fe, foliar fertilization of Zn @ 0.5% + Fe @ 0.1% at flowering stage recorded significantly higher grain yield (1321 kgha-1), net returns (₹ 31179ha-1) and B: C ratio (2.44) over rest of the treatments. Further, foliar fertilization of Zn + Fe had significant influence on nutrient concentration (Zn and Fe) in chickpea grains. Thus, it could be concluded that combined biofortification of Zn + Fe to chickpea crop could be the viable agronomic intervention for getting higher productivity and nutritional security.

scholarly journals Variations in Growth and Yield of Indigenous Hyacinth Bean (Lablab purpureus (L.) Sweet) Genotypes

2015 ◽  
Vol 12 (2) ◽  
pp. 01-05
Author(s):  
H Barua ◽  
M H Rahman ◽  
M M Alam Patwary ◽  
M Zahirul Alam ◽  
S Nahar
Keyword(s):  
Agricultural Research ◽  
Minimum Weight ◽  
Growth And Yield ◽  
Research Station ◽  
Lablab Purpureus ◽  
Maximum Weight ◽  
Agricultural Research Institute ◽  
Green Seed ◽  
Minimum Number ◽  
Hyacinth Bean

Variations in growth and yield of three hyacinth bean genotypes collected from Sitakundu of Chittagong, were investigated at the Agricultural Research Station (ARS) of Bangladesh Agricultural Research Institute (BARI), Pahartali, Chittagong during November 2011 to March 2012, where BARI Seem-4 was used as standard control. The minimum number of days for pod formation (54 days) was recorded in BARI Seem-4, while the maximum was in DLP 002 (62 days). The highest number of pods (324) per plant was obtained from DLP 001 followed by DLP 003 (212.33) and the lowest (148.33) was obtained from BARI Seem-4. The maximum weight (12.61 g) of single pod was observed in DLP 003, which is close to that of DLP 002 (12.23 g). The minimum weight of single pod (7.08g) was however observed in DLP 001. Weight of 100-green seed (117.17 g) was maximum in DLP 002, while that of DLP 001 was the minimum (85.90 g).The maximum green seed (61.86 %) was found in DLP 003 and the minimum was in DLP 001 (47.89 %). DLP 003 produced the highest pod yield (26.77 t/ha) which was followed by DLP 001 (22.94 t/ha), while BARI Seem-4 produced the lowest (17.43 t/ha), which is close to that of DLP 002 (19.57 t/ha).The Agriculturists 2014; 12(2) 01-05

Sign in / Sign up

Export Citation Format

Share Document