scholarly journals Broad-sense Heritability Estimates for Fruit Color and Morphological Traits from Open-pollinated Half-sib Mango Families

HortScience ◽  
2009 ◽  
Vol 44 (6) ◽  
pp. 1552-1556 ◽  
Author(s):  
J. Steven Brown ◽  
Raymond J. Schnell ◽  
Tomás Ayala-Silva ◽  
J. Michael Moore ◽  
Cecile L. Tondo ◽  
...  

The visual appearance of mangos is a primary factor in determining consumer acceptance and sale, similar to other fruit and vegetable commodities. Even if the appeal of visual appearance is based on consumer perception rather than on established quality factors, breeders must usually select within the range of acceptance, at least in some countries. Mango selection using multiyear breeding programs is slowly replacing the former method by which most earlier cultivars were selected, namely from chance seedlings either from planned or unplanned crosses. The knowledge of heritability of traits as they are controlled by genetics and experimental design and the effects and interaction of these two sets of factors on achieved gain have become more critical. The use of portable colorimeters has been shown to give repeatable scores in a quantitative, three-dimensional space for fruits and vegetables. In this experiment, we calculated broad-sense heritability estimates for five color traits, three morphological fruit traits, and one disease resistance trait (anthracnose expressed on the fruit). Estimates were found to be relatively high, indicating good potential for improvement through breeding. For nearly all traits measured, variance within families was greater than that among families, illustrating the likely importance of heterozygosity, dominance, and epistasis in these crosses. The careful estimation of heritability and repeatability will help prioritize and increase the efficiency of trait improvement as breeding methods become more sophisticated and competition for funding increases.

2004 ◽  
Vol 34 (2) ◽  
pp. 505-510 ◽  
Author(s):  
Marcelo Renato Alves de Araújo ◽  
Bruce Coulman

Meadow bromegrass (Bromus riparius Rehm.) is a recently introduced pasture grass in western Canada. Its leafy production and rapid regrowth have made it a major grass species for pasturing beef animals in this region. As relatively little breeding work has been done on this species, there is little information on its breeding behaviour. The main objective of this study was to estimate total genetic variability, broad-sense heritability, phenotypic and genetic correlations. Forty-four meadow bromegrass clones were evaluated for agronomic characters. Genetic variation for dry matter yield, seed yield, fertility index, harvest index, plant height, plant spread, crude protein, neutral detergent fiber and acid detergent fiber, was significant. Broad-sense heritability estimates exceeded 50% for all characters. Heritability estimates were at least 3.5 times greater than their standard errors. Phenotypic and genetic correlation between all possible characters were measured. There was general agreement in both sign and magnitude between genetic and phenotypic correlations. Correlations between the different characters demonstrated that it is possible to simultaneously improve seed and forage yield. Based on the results, it appears that the development of higher yielding cultivars with higher crude protein, and lower acid and neutral detergent fibers concentration should be possible.


HortScience ◽  
2018 ◽  
Vol 53 (4) ◽  
pp. 416-420 ◽  
Author(s):  
Austin L. Grimshaw ◽  
Yuanshuo Qu ◽  
William A. Meyer ◽  
Eric Watkins ◽  
Stacy A. Bonos

In recent years, turfgrass breeders have given increased attention to the development of lower maintenance turfgrass cultivars. Fine fescues (Festuca spp.) have been identified as potential candidate species for low-maintenance lawns because of their reduced need for water, mowing, and fertilizer. Unfortunately, these species have some weaknesses that must be improved to facilitate their use; perhaps, the most important of these is tolerance to wear and traffic. For this trait to be improved in new cultivars, there must be sufficient heritable variation available for plant breeders to exploit; however, little is known about the heritability of this complex trait in fine fescue species. Therefore, the objective of this study was to determine the heritability of wear and traffic tolerance in three fine fescue species. Replicated field studies were established in North Brunswick, NJ, and St. Paul, MN, and each included 157 Chewing’s fescue (Festuca rubra L. subsp. fallax), 155 hard fescue (Festuca brevipilia), and 149 strong creeping red fescue (F. rubra L. subsp. rubra) genotypes. Wear tolerance was evaluated in North Brunswick and traffic tolerance was evaluated in St. Paul during 2015 and 2016 using different simulators to determine both plant performance and broad-sense heritability estimates for wear and traffic tolerance. Broad-sense heritability estimates for the three species when calculated on a clonal basis was between 0.69 and 0.82 for wear tolerance in the North Brunswick location and between 0.49 and 0.60 for traffic tolerance in the St. Paul location. On a single-plant basis, broad-sense heritability estimates for the three species were between 0.31 and 0.45 for wear tolerance in the North Brunswick location and 0.09 and 0.12 for traffic tolerance in St. Paul. However, this research does indicate that improvement of wear and traffic tolerance in fine fescues is possible through recurrent breeding methods based on selection of replicated clonally propagated genotypes rather than selection of single individual plants of a population. This was the first study to determine the genetic effects of wear and traffic tolerance in any turfgrass species.


2006 ◽  
Vol 36 (9) ◽  
pp. 2148-2156 ◽  
Author(s):  
Salvador A Gezan ◽  
Timothy L White ◽  
Dudley A Huber

Clonal testing was studied under different environmental patterns and experimental designs through simulation with the criteria of maximizing broad-sense heritability estimates and genetic gain from clonal selection. Several experimental designs were studied together with three patterns of environmental variability. In addition, empirical 95% confidence intervals for heritability estimates were compared with Dickerson's approximate method. Other elements studied included (i) conditions under which different environmental patterns yield high or low heritabilities and (ii) effects of varying the number of ramets per clone. Row-column designs produced the highest mean individual broad- sense heritability, but these designs were only slightly more efficient than incomplete block designs with small block sizes. For all experimental designs, Dickerson's approximate method for estimating the variance of heritability estimates produced reasonable 95% confidence intervals but overestimated the upper confidence limit of complex designs. Larger heritabilities were found with higher tree-to-tree spatial correlations and lower amounts of microsite residual variance, and varying gradients had negligible influence. The effect of implementing Latinization was significant on increasing heritability, but small in practical terms, and was more important for patchy surfaces. Experiments with more ramets per clone yielded higher clonal mean heritabilities, and using between four and six ramets per clone per site is recommended.


2017 ◽  
Vol 42 (3) ◽  
pp. 219-237 ◽  
Author(s):  
Witold Czajewski ◽  
Krzysztof Kołomyjec

AbstractThis paper describes the results of experiments on detection and recognition of 3D objects in RGB-D images provided by the Microsoft Kinect sensor. While the studies focus on single image use, sequences of frames are also considered and evaluated. Observed objects are categorized based on both geometrical and visual cues, but the emphasis is laid on the performance of the point cloud matching method. To this end, a rarely used approach consisting of independent VFH and CRH descriptors matching, followed by ICP and HV algorithms from the Point Cloud Library is applied. Successfully recognized objects are then subjected to a classical 2D analysis based on color histogram comparison exclusively with objects in the same geometrical category. The proposed two-stage approach allows to distinguish objects of similar geometry and different visual appearance, like soda cans of various brands. By separating geometry and color identification phases, the applied system is still able to categorize objects based on their geometry, even if there is no color match. The recognized objects are then localized in the three-dimensional space and autonomously grasped by a manipulator. To evaluate this approach, a special validation set was created, and additionally a selected scene from the Washington RGB-D Object Dataset was used.


1991 ◽  
Vol 116 (4) ◽  
pp. 724-727 ◽  
Author(s):  
Creighton L. Gupton ◽  
Barbara J. Smith

Experiments were conducted to estimate the relative importance of additive and dominance genetic variances and non-allelic interactions in the inheritance of resistance to Colletotrichum spp. in strawberry (Fragaria × ananassa Duch.). Progeny of 40 parents crossed in a Comstock and Robinson Design II Mating scheme were inoculated with three isolates of C. fragariae and one isolate of C. acutatum. Disease development on each plant was rated visually. Variance components were estimated and converted to genetic variances. Estimates of were six to 10 times higher than those for Within-family variance not accounted for by equaled 35% and 38% of the total genetic variance in females and males, respectively, indicating probable epistatic effects. The frequency distribution of disease severity ratings was bimodal in both experiments, suggesting major gene action. Narrow-sense heritability estimates were 0.37 and 0.26, and broad-sense heritability estimates were 0.87 and 0.85 for females and males, respectively. Narrow-sense heritability estimates are probably sufficient to produce gains from recurrent selection. Gains from selection of clonal value should be possible because of the high broad sense heritability estimates. It appears feasible to establish a broad genetic-based population resistant to Colletotrichum spp. from which selections could be evaluated per se and/or recombined to produce improved populations.


HortScience ◽  
2012 ◽  
Vol 47 (9) ◽  
pp. 1228-1233 ◽  
Author(s):  
Matthew D. Clark ◽  
Eric Watkins

Prairie junegrass [Koeleria macrantha (Ledeb.) Shultes] is a perennial, short-grass prairie species distributed throughout the Northern Hemisphere that is being evaluated for use as a low-input turf. In June 2007, 300 genotypes representing collection locations derived from Colorado, Nebraska, and Minnesota germplasm were grown and evaluated 3 years for turfgrass performance characteristics in a randomized complete block design with five clonal replications at two locations (St. Paul, MN, and Becker, MN). After establishment, plots received no supplemental irrigation or fertility and were mowed weekly to a height of 6.4 cm. Broad-sense heritability estimates were calculated on a clonal mean (Hc) and single-plant (Hsp) basis for turf quality (Hc = 0.62, Hsp = 0.13), crown density (Hc = 0.55, Hsp = 0.09), mowing quality (Hc = 0.59, Hsp = 0.09), and genetic color (Hc = 0.45, Hsp = 0.06). The heritability estimates indicate that selection for these traits should result in significant gains in germplasm improvement. Differences were observed in the means and variances among clones, collection locations, and/or collection regions for many of the traits evaluated including rust severity (Puccinia spp.), spring green-up, plant height, lateral spread, vertical regrowth, and flowering traits. The positive correlations among some of these traits and those with moderate heritability estimates should allow for multi-trait selection in cultivar development.


1982 ◽  
Vol 62 (4) ◽  
pp. 861-865 ◽  
Author(s):  
P. HUCL ◽  
W. D. BEVERSDORF

Broad sense heritability estimates (H) for ozone (O3) insensitivity in four P. vulgaris F2 populations were high (0.66–0.88) under artifical fumigation conditions. In the F3, under field conditions, broad sense H in two populations had declined to 0.16 and 0.21, probably as a result of the interaction of maturity and injury. The results suggest that selection for O3 insensitivity in early generations should be conducted under controlled fumigation conditions followed by field evaluations as lines approach homozygosity.


2016 ◽  
Vol 35 (2) ◽  
pp. 119 ◽  
Author(s):  
Kristamtini Kristamtini ◽  
Sutarno Sutarno ◽  
Endang Wisnu Wiranti ◽  
Setyorini Widyayanti

Black rice is a local rice variety with some advantages and weaknesses. The desirable character of black rice is its high anthocyanin content, while the weaknesses are late maturing, tall plant stature and low grain yield. Crosses were made between two parents aimed to recombine the superior traits. The effectiveness and efficiency of selection would be determined by the magnitude of the heritability of traits and the selection progress. This study was aimed to determine the heritability estimates in a broad sense and the genetic advance of agronomic characters of F2 generation, from crosses of local black rice and high yielding variety of white rice. The experiment was conducted in Padasan, Pakembinangun, Pakem, Sleman, Yogyakarta from January to May 2013. The F2 population derived from crosses of black rice x white rice, with the morphological traits of hairless black rice (S) crossed with Situbagendit (G) white rice, Cempo ireng (C) with Situbagendit (G) and Cempo ireng (C) with Inpari 6 (I). The F2 plants population were planted without replication. Genetic parameters estimated were calculated for broad sense heritability and genetic advance from selection. Results showed that the F2 population had high broad sense heritability estimates for all characters observed, including: plant height, flag leaf length, number of productive tillers, panicle length, number of filled grains per panicle, number of empty grains per panicle, maturity and rice color, in the three F2 populations obtained from crosses of S x G, C x G and C x I. Only the plant height of S x G cross had a medium broad sense heritability estimate. The large heritability estimates indicated that the respective character was controlled by genetic factor more than environmental ones. High genetic advance would be obtained in the flag leaf length, number of productive tillers, panicle length, number of filled grains/panicle, number of empty grains/panicle and rice color from S x G, C x G and C x I crosses. Genetic advance of plant height was medium (at S x G and C x I crosses) to high (C x G crosses). The maturity trait had low genetic advance on cross S x G; C x G; and Cx I. The high value of genetic advance of character would suggest that selection on the character’s appearance would be successful.


Author(s):  
David A. Agard ◽  
Yasushi Hiraoka ◽  
John W. Sedat

In an effort to understand the complex relationship between structure and biological function within the nucleus, we have embarked on a program to examine the three-dimensional structure and organization of Drosophila melanogaster embryonic chromosomes. Our overall goal is to determine how DNA and proteins are organized into complex and highly dynamic structures (chromosomes) and how these chromosomes are arranged in three dimensional space within the cell nucleus. Futher, we hope to be able to correlate structual data with such fundamental biological properties as stage in the mitotic cell cycle, developmental state and transcription at specific gene loci.Towards this end, we have been developing methodologies for the three-dimensional analysis of non-crystalline biological specimens using optical and electron microscopy. We feel that the combination of these two complementary techniques allows an unprecedented look at the structural organization of cellular components ranging in size from 100A to 100 microns.


Author(s):  
K. Urban ◽  
Z. Zhang ◽  
M. Wollgarten ◽  
D. Gratias

Recently dislocations have been observed by electron microscopy in the icosahedral quasicrystalline (IQ) phase of Al65Cu20Fe15. These dislocations exhibit diffraction contrast similar to that known for dislocations in conventional crystals. The contrast becomes extinct for certain diffraction vectors g. In the following the basis of electron diffraction contrast of dislocations in the IQ phase is described. Taking account of the six-dimensional nature of the Burgers vector a “strong” and a “weak” extinction condition are found.Dislocations in quasicrystals canot be described on the basis of simple shear or insertion of a lattice plane only. In order to achieve a complete characterization of these dislocations it is advantageous to make use of the one to one correspondence of the lattice geometry in our three-dimensional space (R3) and that in the six-dimensional reference space (R6) where full periodicity is recovered . Therefore the contrast extinction condition has to be written as gpbp + gobo = 0 (1). The diffraction vector g and the Burgers vector b decompose into two vectors gp, bp and go, bo in, respectively, the physical and the orthogonal three-dimensional sub-spaces of R6.


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