Comparative response of closely related species to reduced competition. I. Senecio sylvaticus and S. viscosus

1968 ◽  
Vol 46 (3) ◽  
pp. 225-228 ◽  
Author(s):  
I. G. Palmblad
Keyword(s):  
Seed Production ◽  
Related Species ◽  
Dry Weight ◽  
Experimental Population ◽  
Closely Related Species ◽  
Flowering Date ◽  
Comparative Response ◽  
Delayed Flowering ◽  
Senecio Sylvaticus ◽  
Number Of Seeds

A comparison of the reproductive and vegetative responses of Senecio sylvaticus and Senecio viscosus to the time and intensity of reduced competition is reported. The two species reacted similarly to thinning in terms of (1) reduced seed production per experimental population and increased seed production per individual, (2) reduced head production, (3) reduced vegetative dry weight, and (4) increased plant height.The two species of Senecio differed in their reaction to thinning in terms of (1) initial anthesis, (2) number of seeds per head, and (3) mortality. Thinning had no significant effect in altering the initial flowering of S. sylvaticus. Early thinning in S. viscosus advanced the flowering date while late thinning delayed flowering. S. sylvaticus was capable of increasing the number of seeds per head only if thinning occurred early, whereas the number of seeds per head in S. viscosus significantly increased at all thinning periods. Lastly, S. sylvaticus experienced much heavier mortality than S. viscosus.

scholarly journals Cortinarius alpinus as an example for morphological and phylogenetic species concepts in ectomycorrhizal fungi

Sommerfeltia ◽  
2008 ◽  
Vol 31 (1) ◽  
pp. 161-177 ◽  
Author(s):  
U. Peintner
Keyword(s):  
Ectomycorrhizal Fungi ◽  
Related Species ◽  
Dry Weight ◽  
Species Concepts ◽  
Its Sequences ◽  
Phylogenetic Species ◽  
Closely Related Species ◽  
Rdna Its ◽  
Rdna Its Sequences ◽  
Distinguishing Character

Cortinarius alpinus as an example for morphological and phylogenetic species concepts in ectomycorrhizal fungiExtensive morphological and molecular analyses of closely related species from alpine, subalpine and montane habitats should enable a comparison of ecological, morphological and phylogenetic species concepts in ectomycorrhizal mushrooms. One fundamental question of this study was whether alpine species really exist, and which criteria, besides the specific habitat, could reliably be used for the de-limitation of such taxa. For this reason, 56 rDNA ITS sequences were generated or downloaded from GenBank for 10 closely related species of Cortinarius subgenus Myxacium, section Myxacium. Several collections were sequenced for each of the following taxa: Cortinarius absarokensis, C. alpinus, C. favrei, C. fennoscandicus, C. grallipes, C. mucosus, C. muscigenus, C. septentrionalis, C. trivialis and C. vernicosus. Moreover, spore statistics were carried out for 38 collections of alpine and subalpine taxa. These data provide clear evidence for C. favrei being a synonym of C. alpinus. C. absarokensis and C. alpinus can clearly be delimited based on pileus diameter and average dry weight per basidiome, even in overlapping habitats, but spore size and shape is not a good distinguishing character. Phylograms have very short branches, and base differences between ITS sequences are generally very low in this group, and give no resolution for the included taxa of this section. Based on these results, species concepts of ectomycorrhizal mushrooms are discussed in detail.

Effect of Shade on Velvetleaf (Abutilon theophrasti) Growth, Seed Production, and Dormancy

1995 ◽  
Vol 9 (3) ◽  
pp. 452-455 ◽  
Author(s):  
Iliya A. Bello ◽  
Micheal D. K. Owen ◽  
Harlene M. Hatterman-Valentp
Keyword(s):  
Plant Height ◽  
Seed Production ◽  
Seed Weight ◽  
Dry Weight ◽  
Growing Season ◽  
Abutilon Theophrasti ◽  
Leaf Number ◽  
Number Of Leaves ◽  
Number Of Seeds ◽  
Number Of Branches

Growth, seed production, and dormancy of velvetleaf in response to shading were evaluated in the field. Velvetleaf plant height, leaf number, number of branches, and plant dry weight decreased linearly with increasing shade. No differences were observed for plant height, number of leaves, or branches/plant when plants were shaded 30% or not shaded throughout the growing season. However, the 76% shade treatment reduced velvetleaf height (1984 only), leaf number, stem branches, and plant dry weight. These reductions were greater in 1984 than 1985 except for plant dry weight that decreased by 88% each year. The number of capsules and the number of seeds/plant decreased linearly with increasing shade levels, while the seed weight increased with increasing shade level. Shading also decreased seed dormancy. These results demonstrate that shade suppresses velvetleaf growth and seed production, and shortens the dormancy of seeds that are produced by these plants.

Microsatellite Marker: Importance and Implications of Cross-genome Analysis for Finger Millet (Eleusine coracana (L.) Gaertn)

2020 ◽  
Vol 9 (3) ◽  
pp. 160-170
Author(s):  
Thumadath P.A. Krishna ◽  
Maharajan Theivanayagam ◽  
Gurusunathan V. Roch ◽  
Veeramuthu Duraipandiyan ◽  
Savarimuthu Ignacimuthu
Keyword(s):  
Molecular Marker ◽  
Microsatellite Markers ◽  
Ssr Markers ◽  
Genome Analysis ◽  
Related Species ◽  
Finger Millet ◽  
Crop Improvement ◽  
Human Beings ◽  
Closely Related Species ◽  
Genome Amplification

Finger millet is a superior staple food for human beings. Microsatellite or Simple Sequence Repeat (SSR) marker is a powerful tool for genetic mapping, diversity analysis and plant breeding. In finger millet, microsatellites show a higher level of polymorphism than other molecular marker systems. The identification and development of microsatellite markers are extremely expensive and time-consuming. Only less than 50% of SSR markers have been developed from microsatellite sequences for finger millet. Therefore, it is important to transfer SSR markers developed for related species/genus to finger millet. Cross-genome transferability is the easiest and cheapest method to develop SSR markers. Many comparative mapping studies using microsatellite markers clearly revealed the presence of synteny within the genomes of closely related species/ genus. Sufficient homology exists among several crop plant genomes in the sequences flanking the SSR loci. Thus, the SSR markers are beneficial to amplify the target regions in the finger millet genome. Many SSR markers were used for the analysis of cross-genome amplification in various plants such as Setaria italica, Pennisetum glaucum, Oryza sativa, Triticum aestivum, Zea mays and Hordeum vulgare. However, there is very little information available about cross-genome amplification of these markers in finger millet. The only limited report is available for the utilization of cross-genome amplified microsatellite markers in genetic analysis, gene mapping and other applications in finger millet. This review highlights the importance and implication of microsatellite markers such as genomic SSR (gSSR) and Expressed Sequence Tag (EST)-SSR in cross-genome analysis in finger millet. Nowadays, crop improvement has been one of the major priority areas of research in agriculture. The genome assisted breeding and genetic engineering plays a very crucial role in enhancing crop productivity. The rapid advance in molecular marker technology is helpful for crop improvement. Therefore, this review will be very helpful to the researchers for understanding the importance and implication of SSR markers in closely related species.

Genetic Complexity Underlying Hybrid Male Sterility in Drosophila

Genetics ◽  
2004 ◽  
Vol 166 (2) ◽  
pp. 789-796 ◽  
Author(s):  
Kyoichi Sawamura ◽  
John Roote ◽  
Chung-I Wu ◽  
Masa-Toshi Yamamoto
Keyword(s):  
Male Sterility ◽  
Related Species ◽  
Synergistic Effects ◽  
Female Sterility ◽  
Hybrid Male ◽  
Hybrid Female ◽  
Hybrid Male Sterility ◽  
Closely Related Species ◽  
Genetic Complexity ◽  
Recessive Genes

Abstract Recent genetic analyses of closely related species of Drosophila have indicated that hybrid male sterility is the consequence of highly complex synergistic effects among multiple genes, both conspecific and heterospecific. On the contrary, much evidence suggests the presence of major genes causing hybrid female sterility and inviability in the less-related species, D. melanogaster and D. simulans. Does this contrast reflect the genetic distance between species? Or, generally, is the genetic basis of hybrid male sterility more complex than that of hybrid female sterility and inviability? To clarify this point, the D. simulans introgression of the cytological region 34D-36A to the D. melanogaster genome, which causes recessive male sterility, was dissected by recombination, deficiency, and complementation mapping. The 450-kb region between two genes, Suppressor of Hairless and snail, exhibited a strong effect on the sterility. Males are (semi-)sterile if this region of the introgression is made homozygous or hemizygous. But no genes in the region singly cause the sterility; this region has at least two genes, which in combination result in male sterility. Further, the males are less fertile when heterozygous with a larger introgression, which suggests that dominant modifiers enhance the effects of recessive genes of male sterility. Such an epistatic view, even in the less-related species, suggests that the genetic complexity is special to hybrid male sterility.

Sign in / Sign up

Export Citation Format

Share Document