Predicted Evolutionary Response to Selection for Tolerance of Soybean (Glycine max) and Intraspecific Competition in a Nonweed Population of Poorjoe (Diodia teres)

Weed Science ◽  
1989 ◽  
Vol 37 (3) ◽  
pp. 451-457 ◽  
Author(s):  
Nicholas Jordan
Keyword(s):  
Multivariate Analysis ◽  
Genetic Variation ◽  
Intraspecific Competition ◽  
Path Coefficient ◽  
Experimental Population ◽  
Response To Selection ◽  
Weed Population ◽  
Evolutionary Response ◽  
Soybean Canopy ◽  
Selection For

Genetic variation within a nonweed (coastal) population of poorjoe was measured in an experimental population subjected to soybean and intraspecific competition for space and light. A sib analysis was used to estimate phenotypic and genetic variance/covariance components of aboveground biomass production and five independent measurements of growth defined by a path-coefficient model. A multivariate analysis of response to selection was applied to predict evolutionary change in the growth measurements in response to selection for performance under soybean and intraspecific space/light competition; sufficient genetic variation was present in the experimental population to allow a rapid response to this selection. Selection under competitive conditions was predicted to cause the nonweed population to emerge earlier, grow faster early in development, change in growth form, and grow faster under a soybean canopy. Most of these changes would increase the resemblance of the selected population to a weed population of poorjoe. However, the growth rate of the selected population under a soybean canopy was predicted to become greater than that actually observed in the present-day weed population. Multivariate analysis of response to selection may be generally useful in predicting evolutionary response of plant pest populations to control practices.

Breeding for improved nutritive value of Phalaris tuberosa herbage: an evaluation of alternative sources of genetic variation

1973 ◽  
Vol 24 (1) ◽  
pp. 21 ◽  
Author(s):  
RJ Clements
Keyword(s):  
Genetic Variation ◽  
Nitrogen Content ◽  
Nutritive Value ◽  
Negative Relationship ◽  
Heading Date ◽  
Breeding Program ◽  
Response To Selection ◽  
Annual Species ◽  
Selection For ◽  
Heading Stage

The variation in herbage nitrogen content and in vitro organic matter digestibility (IVDOM) among Phalaris species and hybrids, within an Algerian ecotype of P. tuherosa and among plants derived from a broadly based P. tuberosa breeding population, was examined. Variation was extensive in each of the three populations, and appears adequate for plant breeding purposes. In each population, IVDOM was negatively related to heading date. Another feature common to all populations at the heading stage was a negative relationship between WDOM and nitrogen content, demonstrable particularly when other factors having similar effects on both characters were held constant. In mature herbage of the P. tuberosa ecotype there was a positive genetic correlation between nitrogen content and IVDOM, but IVDOM at maturity was negatively related to nitrogen content at heading. Annual Phalaris species had higher average IVDOM values at heading (mean 70.5 %) than perennial species (mean 66.1 %) when data were adjusted to a common heading date. Although there was considerable intraspecific variation, only the annual species were sufficiently superior to the best P. tuberosa strains to warrant consideration for hybridizing with P. tuberosa. Since such hybrids have reduced perenniality, and are cytologically unstable, interspecific hybridization appears to have the least value as a source of herbage quality for a P. tuberosa breeding program. In addition, annual species were lower in nitrogen content (mean 1 .15 %) than perennials (mean 1.70 %) at a common heading date. Estimated heritabilities of IVDOM and nitrogen content of mature herbage of the P. tuberosa ecotype were 0.78 and 0.59 respectively, for a family mean based on replicated eight-plant rows. Genetic statistics indicated that a substantial response to selection for improved digestibility of mature herbage would be accompanied by a correlated increase in IVDOM at heading, a slight increase in nitrogen content at maturity, a decrease in nitrogen content at heading, little change in heading date, and perhaps some increase in the weight of individual tillers. Response to selection for increased nitrogen content would be small, and would be accompanied by a reduction in tiller weight. Individual plants derived from the broadly based population ranged from 56 to 76% IVDOM at the heading stage. This population, because of its agronomic superiority, is considered to be the most suitable source of genetic variation on which to base a breeding program.

scholarly journals Recurrent evolution of cross-resistance in response to selection for improved post-infection survival in Drosophila melanogaster

2021 ◽  
Author(s):  
Aparajita Singh ◽  
Aabeer Basu ◽  
Biswajit Shit ◽  
Tejashwini Hegde ◽  
Nitin Bansal ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Bacterial Pathogen ◽  
Host Population ◽  
Host Susceptibility ◽  
Cross Resistance ◽  
Response To Selection ◽  
Host Sex ◽  
Determining Factors ◽  
Selection For

The host susceptibility to one pathogen can decrease, increase, or remain unaffected by virtue of the host evolving resistance towards a second pathogen. Negative correlations between a host susceptibility to different pathogens is an often-cited explanation for maintenance of genetic variation in immune function determining traits in a host population. In this study, we investigated the change in susceptibility of Drosophila melanogaster flies to various novel bacterial pathogens after being experimentally selected for increased resistance to one particular bacterial pathogen. We independently selected flies to become more resistant towards Enterococcus faecalis and Pseudomonas entomophila, and baring a few exceptions the evolved populations exhibited cross-resistance against the range of pathogens tested in the study. Neither the identity of the native pathogen nor the host sex was major determining factors in predicting the pattern of cross-resistance exhibited by the selected populations. We therefore report that a generalized cross-resistance to novel pathogens can repeatedly evolve in response to selection for resistance against a single pathogen.

scholarly journals Genetic Variation and Selection for Carotene Content in Carrots

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 821E-821
Author(s):  
Philipp Simon
Keyword(s):  
Genetic Variation ◽  
Combining Ability ◽  
General Combining Ability ◽  
Mass Selection ◽  
Realized Heritability ◽  
Response To Selection ◽  
Carotene Content ◽  
Selection For ◽  
Variation And Selection ◽  
Made In

A six-parent diallel which included carrot inbreds with a range of carotene content from 80 to 490 ppm was evaluated over 2 years. General combining ability accounted for most of the variation observed. Phenotypic mass selection was exercised for high carotene content in three carrot populations. Response to selection continued to be high in one population, HCM, after 11 cycles of selection. In contrast, after three generations of selection, little progress was able to be made in a population derived from primarily Nantes-type open-pollinated cultivars. Realized heritability estimates varied from 15% to 49%. Environment contributed significantly to variation in carotene content.

Spatial patterns of genetic variability in Italian chestnut (Castanea sativa)

1990 ◽  
Vol 68 (9) ◽  
pp. 1962-1967 ◽  
Author(s):  
M. Pigliucci ◽  
S. Benedettelli ◽  
F. Villani
Keyword(s):  
Multivariate Analysis ◽  
Genetic Variation ◽  
Spatial Autocorrelation ◽  
Spatial Patterns ◽  
Castanea Sativa ◽  
The Other ◽  
Spatial Autocorrelation Analysis ◽  
Autocorrelation Analysis ◽  
Migration Flow ◽  
Selection For

The spatial patterns of genetic variation for 15 loci in 18 Italian populations of chestnut were analyzed. Multivariate analysis and spatial autocorrelation analysis showed two clinal variations, one in a west–east direction, the other in a north–south direction. There was a nonrandom spatial pattern of at least three alleles and a marked heterogeneity among populations of many others. An explanation is proposed in terms of migration flow for the majority of the polymorphisms and of selection for the three autocorrelated alleles. However, anthropic interferences may also be important. Key words: chestnut, electrophoresis, spatial autocorrelation, correspondence analysis, genetic boundaries, discriminant analysis.

scholarly journals Genotype by environment interactions for the shade avoidance syndrome in the plant Antirrhinum majus, the snapdragon

2018 ◽  
Author(s):  
Mathilde Mousset ◽  
Sara Marin ◽  
Juliette Archambeau ◽  
Christel Blot ◽  
Vincent Bonhomme ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Natural Populations ◽  
Common Garden ◽  
Antirrhinum Majus ◽  
Shade Avoidance ◽  
Response To Selection ◽  
Plastic Response ◽  
Genetic Constraints ◽  
Shade Avoidance Syndrome ◽  
Evolutionary Response

AbstractA classical example of phenotypic plasticity in plants is the set of trait changes in response to shade, i.e. the shade avoidance syndrome. There is widespread evidence that plants in low light conditions often avoid shade by growing taller or by increasing their photosynthetic efficiency. This plastic response is expected to have evolved in response to selection in several species, yet there is limited evidence for its genetic variation within populations, which is required for any evolutionary response to selection. In this study, we investigated the shade avoidance syndrome in snapdragon plants (Antirrhinum majus) by using a common garden approach on four natural populations from the Mediterranean region. Our results showed that, in the four populations, individual plants reacted strongly to the presence of shade by growing longer shoots, longer internodes, and increasing their specific leaf area. Our results also revealed genetic variation for the plastic response within these populations, as well as few genetic constraints to its evolution. Our findings imply that the plastic response to shade has the potential to evolve in response to selection in natural populations of A. majus.

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