GENETIC SOURCES OF RESISTANCE TO BLACKBIRD PREDATION IN SUNFLOWER

1986 ◽  
Vol 66 (1) ◽  
pp. 19-23 ◽  
Author(s):  
DAN E. PARFITT ◽  
GREGORY J. FOX
Keyword(s):  
Agelaius Phoeniceus ◽  
Narrow Sense ◽  
Sources Of Resistance ◽  
Bird Predation ◽  
Narrow Sense Heritability ◽  
The Third ◽  
Naturally Occurring ◽  
Xanthocephalus Xanthocephalus ◽  
Sib Families ◽  
Highly Correlated

Fifty-one sunflower (Helianthus annuus L.) inbreds were grown at three environments (locations) in North Dakota. Inbreds at two locations were subjected to naturally occurring bird predation by redwinged blackbirds (Agelaius phoeniceus L.) and yellowheaded blackbirds (Xanthocephalus xanthocephalus Bonaparte). The third sunflower plot was surrounded by a cage into which redwinged blackbirds were introduced. Bird damage was estimated as percent achenes removed from individual sunflower heads. Significant differences among environments were observed (P < 0.01). However, genotype performance among environments was highly correlated (P < 0.01). Half sib progeny from 36 of these inbreds were grown along with their maternal inbred parents to estimate narrow sense heritability (h2NS) of resistance to bird predation. Estimates of h2NS obtained by parent offspring regression and by covariance among half-sib families were h2NS = 0.69 and h2NS = 0.66, respectively. These estimates indicate a 67% level of heritability for resistance to bird predation, and suggest that it should be possible to develop sunflower lines with improved resistance.Key words: Sunflower, bird feeding, redwinged blackbird, yellowheaded blackbird

Genetic variation in perennial ryegrass for root profile characteristics

2006 ◽  
Vol 12 ◽  
pp. 63-65
Author(s):  
J.R. Crush ◽  
H.S. Easton ◽  
J.E. Waller
Keyword(s):  
Genetic Variation ◽  
Perennial Ryegrass ◽  
Exponential Model ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Sib Families ◽  
Profile Characteristics ◽  
Low Ionic Strength

Fifteen plants, replicated twice, of each of 20 half-sib families of perennial ryegrass were grown in deep sand tubes irrigated with a low ionic strength nutrient solution in a glasshouse. Top growth was measured. Roots were turned out, cut into 10 cm profile increments, washed free of sand, dried and weighed. For top growth, total root growth and root-shoot ratio, there were significant differences among families translating to narrow sense heritability coefficients between 0.3 and 0.4. However, the ratio between root in the top 10 cm and total root, and a parameter for a well-fitting exponential model describing root profile showed variation between individuals but very little or no variation between families. This translated to narrow sense heritability coefficients of less than 0.1.

scholarly journals Field Resistance to Fire Blight in a Diverse Apple (Malus sp.) Germplasm Collection

2002 ◽  
Vol 127 (2) ◽  
pp. 245-253 ◽  
Author(s):  
James J. Luby ◽  
Peter A. Alspach ◽  
Vincent G.M. Bus ◽  
Nnadozie C. Oraguzie
Keyword(s):  
Fire Blight ◽  
Germplasm Collection ◽  
Field Resistance ◽  
Open Pollination ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Flowering Date ◽  
Effective Selection ◽  
Heritability Estimates ◽  
Highly Correlated

Incidence and severity of fire blight [Erwinia amylovora (Burr.) Winslow, Broadhurst, Buchanan, Krumwiede, Rogers, and Smith] following field infection were recorded using families resulting primarily from open-pollination of Malus sylvestris (L.) Mill. var.domestica (Borkh.) Mansf. cultivars and a few other Malus Mill. sp. The families were structured as three sublines, planted in three successive years (1992 to 1994), of a diverse population of apple germplasm established at HortResearch, Hawkes Bay, New Zealand. The incidence of fire blight varied among the sublines with the oldest planting exhibiting more fire blight. Flowering trees were more likely to be infected than nonflowering trees, in terms of both incidence and severity. Furthermore, the level of fire blight was related to flowering date, with later flowering trees having higher levels. Thus, family means and narrow-sense heritability estimates were computed after first adjusting the fire blight score for flowering date by fitting a linear model. Provenance of origin of the maternal parent explained little variation except that M. sieversii Lebed. families were more resistant than M. sylvestris var. domestica families in one subline. Family means computed using all trees, and those from only flowering trees were highly correlated. Families from open-pollination of M. honanensis Rehder and M. xhartwiggii Koehne females were among the more susceptible. Those from several European M. sylvestris var. domestica cultivars as well as from M. baccata (L.) Borkh. and M. toringoides (Rehder) Hughes females were among the more resistant families. Narrow-sense heritability estimates ranged from 0.05 to 0.85 depending on the subline, with most estimates between 0.12 and 0.36. They were higher in the two older sublines that consisted primarily of open-pollinated families from M. sylvestris var. domestica, and lower in the younger subline that consisted primarily of M. sieversii, due to lower incidence and severity in the latter subline. Breeders who consider potential complications of juvenility, tree size, and flowering date in relation to infection periods should be able to exploit field epidemics to perform effective selection.

scholarly journals Inheritance of Summer Dormancy, Persistence and Productivity Using Half-sib Matting in Tall Fescue 

2020 ◽  
Author(s):  
Fatemeh Pirnajmedin ◽  
Mohammad Mahdi Majidi ◽  
Mohammad Hadi Taleb ◽  
Sayed Ali Mohammad Mirmohammady Maibody
Keyword(s):  
Tall Fescue ◽  
Recurrent Selection ◽  
Gene Action ◽  
Genotypic Variation ◽  
Dominant Gene ◽  
Narrow Sense ◽  
Forage Production ◽  
Narrow Sense Heritability ◽  
Summer Dormancy ◽  
Sib Families

Abstract Background: The genetic basis and variability of persistence and summer dormancy and their association with forage production traits has been less investigated in tall fescue. Results: High genotypic variation was found for all the measured traits in both parental genotypes and half-sib families. Incomplete summer dormancy was found for most of the evaluated genotypes. Summer dormancy index were negatively correlated with forage production and yield related traits. Half-sib families had higher persistence than parental genotypes, which can be due to the heterosis expression in progenies. Moderate narrow-sense heritability for persistence indicates that both additive and dominant gene action may play a role in the expression of this trait. Yield-related traits and summer dormancy showed moderate to high estimates of narrow sense heritability (0.63-0.73) indicates additive gene action for these traits. This suggest phenotypic recurrent selection can be successful to achieve genetic progress. Conclusion: In conclusion, our results can enhance the knowledge of inheritance of summer dormancy and related traits which would be useful for future genetic studies. Based on the general combining ability and application of multivariate analysis, preferable genotypes for forage use (such as 21M and 1E) and turf application (such as 17M and 4E) were identified for future programs.

INHERITANCE OF FLOWERING TIME AND ITS APPLICATION FOR INDIRECT SELECTION IN THE DAVIS POPULATION OF GERBERA

HortScience ◽  
1990 ◽  
Vol 25 (11) ◽  
pp. 1357F-1358
Author(s):  
Yiran Yu ◽  
James Harding ◽  
Thomas Byrne
Keyword(s):  
Flowering Time ◽  
Genetic Correlations ◽  
Indirect Selection ◽  
Cut Flower ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Components Of Variance ◽  
Genetic Components ◽  
Flower Yield ◽  
Cut Flower Yield

Genetic components of variance and heritability of flowering time were estimated for five generations of the Davis Populationof Gerbera hybrids, Composite, Estimates of narrow-sense heritability averaged 0.50 and broad-sense heritability averaged 0.77 using the NCII design. Narrow-sense heritability was also estimated with two models of parent-offspring regression, resulting in average heritability of 0.49 and 0.51. Estimates of components of variance indicated that the major genetic effect controlling flowering time is additive. However, the dominance component accounted for 28% of the total variance; the environmental component was only 23%. Flowering time is negatively correlated with cut-flower yield. The phenotypic coefficient was –0.34; genetic correlations were –0.47 when estimated from the NCII design, and –0.72 when estimated from the parent-off-spring method. A practical model was constructed to assess the efficiency of indirect selection for cut-flower yield using flowering time as a marker trait. The advantages of indirect selection accruing from increased population size and reduced generation time are discussed.

Combining Ability of Plant Height and Yield components in Indian Mustard (Brassica junceaL.Czern & Coss.) under Salt affected Soil using Line×Tester Analysis

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
SHAILESH CHAND GAUTAM ◽  
MP Chauhan
Keyword(s):  
Plant Height ◽  
Seed Yield ◽  
Combining Ability ◽  
Yield Components ◽  
Indian Mustard ◽  
Heritability Estimate ◽  
Genetic Effects ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Additive Genetic Effects

Line × tester analysis of twenty lines and three testers of Indian mustard (Brassica juncea L. Czern & Coss.) cultivars were used to estimate general combining ability (GCA), specific combining ability (SCA) effects, high parent heterosis and narrow-sense heritability estimate for plant height, yield components and seed yield. Significant variance of line x tester for the traits like pods per plant and seed yield indicating non additive genetic effects have important role for controlling these traits. Significant mean squares of parents v/s crosses which are indicating significant average heterosis were also significant for all the traits except seeds per pod. High narrow-sense heritability estimates for all the traits except seeds per pod exhibited the prime importance of additive genetic effects for these traits except seeds per pod. Most of the crosses with negative SCA effect for plant height had at least one parent with significant negative or negative GCA effect for this trait. For most of the traits except pods per plant, the efficiency of high parent heterosis effect was more than SCA effect for determining superior cross combinations.

The Function of a Heteromorph Antennule in a Spiny Lobster, Panulirus Argus

1965 ◽  
Vol 43 (1) ◽  
pp. 55-78
Author(s):  
D. M. MAYNARD ◽  
M. J. COHEN
Keyword(s):  
Motor Neurons ◽  
Spiny Lobster ◽  
Panulirus Argus ◽  
Intracellular Recordings ◽  
Afferent Fibre ◽  
The Third ◽  
Naturally Occurring ◽  
Withdrawal Response ◽  
Basic Similarity ◽  
Stimulation Of

1. The effects of electrical and mechanical stimulation upon a ‘naturally occurring’ heteromorph appendage growing in place of one eyestalk in Panulirus argus were examined. The heteromorph resembled the outer flagellum of the antennule in form. 2. Heteromorph stimulation elicited both a generalized withdrawal response, and a specific depression of the third segment and flagellum of the ipsilateral antennule. Such a depression response was also elicited upon stimulation of the ipsilateral outer flagellum of the normal antennule and by no other input investigated. 3. The basic similarity of the two responses was confirmed by electromyography and by intracellular recordings from motor neurons and interneurons within the lobster brain. 4. It was concluded that at least one afferent fibre component from the heteromorph and normal flagellum terminated upon the same interneuron pools, while avoiding others, and that consequently these observations provide evidence for the formation of functional inter-neuronal connexions according to type specificity.

scholarly journals Genetic Variation for Biomass Yield and Predicted Genetic Gain in Lowland Switchgrass “Kanlow”

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1845
Author(s):  
Santosh Nayak ◽  
Hem Bhandari ◽  
Carl Sams ◽  
Virginia Sykes ◽  
Haileab Hilafu ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Gain ◽  
Panicum Virgatum ◽  
Biomass Yield ◽  
Block Design ◽  
Perennial Grass ◽  
Warm Season ◽  
Narrow Sense ◽  
Bioenergy Feedstock ◽  
Narrow Sense Heritability

Switchgrass (Panicum virgatum L.) is a warm-season, perennial grass valued as a promising candidate species for bioenergy feedstock production. Biomass yield is the most important trait for any bioenergy feedstock. This study was focused on understanding the genetics underlying biomass yield and feedstock quality traits in a “Kanlow” population. The objectives of this study were to (i) assess genetic variation (ii) estimate the narrow sense heritability, and (iii) predict genetic gain per cycle of selection for biomass yield and the components of lignocelluloses. Fifty-four Kanlow half-sib (KHS) families along with Kanlow check were planted in a randomized complete block design with three replications at two locations in Tennessee: Knoxville and Crossville. The data were recorded for two consecutive years: 2013 and 2014. The result showed a significant genetic variation for biomass yield (p < 0.05), hemicellulose concentration (p < 0.05), and lignin concentration (p < 0.01). The narrow sense heritability estimates for biomass yield was very low (0.10), indicating a possible challenge to improve this trait. A genetic gain of 16.5% is predicted for biomass yield in each cycle of selection by recombining parental clones of 10% of superior progenies.

Genetic parameters and genotype–environment interactions of Chinese fir (Cunninghamia lanceolata) in Fujian Province

2014 ◽  
Vol 44 (6) ◽  
pp. 582-592 ◽  
Author(s):  
Liming Bian ◽  
Jisen Shi ◽  
Renhua Zheng ◽  
Jinhui Chen ◽  
Harry X. Wu
Keyword(s):  
Genetic Parameters ◽  
Breeding Strategy ◽  
Chinese Fir ◽  
Breeding Program ◽  
Cunninghamia Lanceolata ◽  
Environment Interaction ◽  
Fujian Province ◽  
The Third ◽  
Genotype Environment Interaction ◽  
Sib Families

Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) is the most commercially important conifer in China, and the Nanjing Forestry University – Fujian Province Chinese fir Cooperation (NJFU – Fujian Cooperation) breeding program has advanced it into the third cycle of selection and breeding. In this paper, we estimated genetic parameters from four sites for 80 half-sib families and summarized previous estimates of genetic parameters in Chinese fir with an objective to propose optimal breeding strategy. Heritability averaged 0.20 and 0.14 for height and diameter at breast height (DBH), respectively, for the four sites. A significant genotype–environment interaction (G × E) for growth was also observed among the four sites, with the greatest interactions between a marginal site and the three central sites in the Fujian Province Chinese fir plantation region. The average estimated type-B genetic correlation between the marginal site and the three central sites was 0.08 for height and –0.09 for DBH. However, the highly productive families were among the most stable across the four sites. The results from this study in combination with summarized genetic parameters from literature were used to discuss and propose an optimal breeding strategy for the third generation of the breeding program for Chinese firs in Fujian Province.

scholarly journals Virulence Phenotypes and Molecular Genotypes in Collections of Puccinia triticina from Italy

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 420-424 ◽  
Author(s):  
Paola Mantovani ◽  
Marco Maccaferri ◽  
Roberto Tuberosa ◽  
James Kolmer
Keyword(s):  
Durum Wheat ◽  
Common Wheat ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Leaf Rust Resistance Gene ◽  
The Third ◽  
Virulence Phenotype ◽  
Ssr Loci ◽  
Highly Correlated ◽  
Simple Sequence

Twenty-four isolates of Puccinia triticina from Italy were characterized for virulence to seedlings of 22 common wheat Thatcher isolines, each with a different leaf rust resistance gene, and for molecular genotypes at 15 simple sequence repeat (SSR) loci. The isolates were compared to a set of 13 previously characterized P. triticina isolates from either durum or common wheat. Clustering based on virulence phenotypes and SSR genotypes grouped the Italian P. triticina isolates into three groups. In the first group, the isolates had virulence phenotypes and SSR genotypes that were similar to the isolates collected from durum wheat. Isolates in the second group were unique because they had virulence similar to the isolates from common wheat but were distinct for SSR genotypes compared to the isolates from durum wheat and from common wheat. Isolates in the third group had virulence phenotypes and SSR genotypes closely related to the isolates from common wheat. The isolates were grouped based on the known or assumed host of origin, virulence phenotype, and SSR genotypes. Measures of FST and RST for SSR genotypes, and ΦST for virulence phenotype were significant, which indicated differentiation among the three groups of isolates. Virulence phenotypes and molecular genotypes were highly correlated with r = 0.74.

scholarly journals Combining ability and heritability of selected rice varieties for grain yield, its components and grain quality characters

Genetika ◽  
2015 ◽  
Vol 47 (2) ◽  
pp. 559-570 ◽  
Author(s):  
Mehrzad Allahgholipour ◽  
Ezatollah Farshdfar ◽  
Babak Rabiei
Keyword(s):  
Grain Yield ◽  
Combining Ability ◽  
Grain Quality ◽  
Amylose Content ◽  
Gelatinization Temperature ◽  
Narrow Sense ◽  
Rice Varieties ◽  
Narrow Sense Heritability ◽  
Head Rice ◽  
Additive Gene

This study was conducted to determine the combining ability and heritability of rice grain yield, its components and some grain quality traits such as amylose content (AC), gelatinization temperature (GT), gel consistency (GC) and head rice recovery (HRR). The study was commenced by crossing the selected rice varieties based on a full diallel mating design. The F1 was harvested at the end of the season. In the following season, the crossed, reciprocal and parental lines were planted in randomly complete block design with three replications. Analysis of variance indicated that genotypes were significantly different for all traits. The diallel analysis by Griffing`s method showed highly significant differences for GCA for number of panicles per plant (PN), amylose content, gelatinization temperature and head rice recovery. Highly significant differences were also observed for both SCA and REC for all evaluated characters. The results showed that the grain yield (GY), number of filled grains (FGN), 100-grain weight (HGW) and GC were controlled by non-additive gene action, while the inheritance of PN, AC, GT and HRR were largely controlled by additive gene effects, although non- additive genetic components and reciprocal effect were also involved, which suggest that a selection process could be done in the early generations. The two improved lines (RI18442-1 and RI18430-46) were found to be good general combiners for GY and FGN, while the best combiners for PN was Tarom Mohali and IR50 and for HGW was RI18430-46. The best combinations for GY were RI18430-46 ? IR50, Tarom Mohali ? RI18447-2 and Daylamani ? RI18430-46. The good hybrids were Tarom Mohali ? IR50, Line23 ? RI18447-2 and Line23 ? Backcross line for AC. Narrow sense heritability showed that the GY and GC had the lowest values while the other traits had either moderate or high heritability, which indicates selection in the early generations could be done to fix the favorable genes. In present study, narrow sense heritability was high for AC and moderate for GT, PN and HRR.

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