Relative susceptibility of sunflower maintainer lines and resistance sources to natural infestations of the banded sunflower moth (Lepidoptera: Tortricidae)

2016 ◽  
Vol 148 (6) ◽  
pp. 736-741 ◽  
Author(s):  
Jarrad R. Prasifka ◽  
Brent S. Hulke

AbstractThe banded sunflower moth, Cochylis hospes Walsingham (Lepidoptera: Tortricidae), is a significant seed-feeding pest of sunflowers (Helianthus Linnaeus; Asteraceae) in North America. Though some wild Helianthus, interspecific crosses, and H. annuus Linnaeus cultivars (which precede hybrid sunflower breeding) have low susceptibility to banded sunflower moth, no apparent effort has been made to evaluate modern inbred lines as a source of resistance for hybrids. In field trials from 2013 to 2015, inbred maintainer (HA) lines, resistant accessions (PI), and unreleased, partially inbred (F6) lines were evaluated in field trials using natural infestations of banded sunflower moth. Results show greater seed damage to maintainer lines than the other groups, but also significant variability among lines within groups. The best maintainer, HA 207, had ≈75% fewer damaged seed than the most susceptible HA lines. Among the resistant PI and unreleased inbred lines, only one entry had significantly less damage than HA 207. While PI 494859 showed banded moth resistance superior to the best inbred lines, its other agronomic liabilities make breeding with the least susceptible maintainer lines appear more practical. A key unknown for any attempts to breed hybrids resistant to banded sunflower moth is how closely damage is correlated between inbred lines and their hybrids.

2019 ◽  
Vol 151 (6) ◽  
pp. 817-823 ◽  
Author(s):  
Jarrad R. Prasifka

AbstractLarvae of Cochylis hospes (Walsingham) (Lepidoptera: Tortricidae) (banded sunflower moth) are a primary source of insect damage to seeds of cultivated sunflower, Helianthus annuus Linnaeus (Asteraceae), in North America. Field trials were used to evaluate seed damage under natural infestations for panels of publicly released male lines, publicly derived hybrids (females crossed to one common male parent), and commercial hybrids over a total of four years. For trials in 2013–2014 including 17 male lines, seed damage ranged from 3% to 19%. The least damaged male, RHA 266, was statistically similar to one other male, RHA 455. Three commercial hybrids used as checks also received very little seed damage (< 5%). In trials during 2016–2017, hybrids created by pollinating 15 different female lines with RHA 266 showed 4–14% damage. Data from female parents explained about 28% of variation in seed damage for the hybrids. Results confirm cultivated sunflower has greater variation in susceptibility to C. hospes than previously believed, and that seed damage to inbred lines provides some predictive power for hybrids. Though breeding for resistance to C. hospes seems possible, it may be too labour-intensive without relating resistance to more easily measurable traits or genetic markers.


2020 ◽  
Vol 49 (2) ◽  
pp. 444-448
Author(s):  
Jarrad R Prasifka ◽  
Brent S Hulke

Abstract Extracts from capitate glandular trichomes (CGT) of wild and cultivated sunflowers, Helianthus spp., have repellent or toxic effects on sunflower specialists and generalist herbivores less closely associated with sunflower. Though CGT have been primarily examined for their potential to provide partial resistance to the sunflower moth, Homoeosoma electellum Hulst (Lepidoptera: Pyralidae), a floret- and seed-feeding pest, the banded sunflower moth (Cochylis hospes Walsingham [Lepidoptera: Tortricidae]) is a similar species more common in the primary sunflower-producing states of North Dakota and South Dakota. Replicated field trials using partially inbred lines with low or high CGT densities were used to evaluate possible reductions to seed damage by C. hospes larvae in 2016–2017. Results failed to support the idea that CGT are a useful defense against larvae of C. hospes; the putative plant defense of high trichome density corresponded to slightly more, rather than less, insect damage. A test of a secondary explanation, that strength of sunflower hulls could help determine patterns of seed damage among tested lines, produced similarly negative results. Though timing of bloom differed between groups of most- and least-damaged lines, prior research and pheromone-trapping data suggest differences in plant maturity also cannot adequately explain the observed results. While the specific mechanisms remain unclear, significant differences in susceptibility to C. hospes exist for cultivated sunflower and limit losses from this primary insect pest.


Genetics ◽  
1996 ◽  
Vol 143 (4) ◽  
pp. 1739-1752 ◽  
Author(s):  
Xavier Montagutelli ◽  
Rowena Turner ◽  
Joseph H Nadeau

Abstract Strong deviation of allele frequencies from Mendelian inheritance favoring Mus spretus-derived alleles has been described previously for X-linked loci in four mouse interspecific crosses. We reanalyzed data for three of these crosses focusing on the location of the gene(s) controlling deviation on the X chromosome and the genetic basis for incomplete deviation. At least two loci control deviation on the X chromosome, one near Xist (the candidate gene controlling X inactivation) and the other more centromerically located. In all three crosses, strong epistasis was found between loci near Xist and marker loci on the central portion of chromosome 2. The mechanism for this deviation from Mendelian expectations is not yet known but it is probably based on lethality of embryos carrying particular combinations of alleles rather than true segregation distortion during oogenesis in F1 hybrid females.


1966 ◽  
Vol 67 (2) ◽  
pp. 235-237 ◽  
Author(s):  
D. A. Bond ◽  
J. L. Fyfe ◽  
Gillian Toynbee-Clarke

The yields of seed from a hybrid, one of its parents and different mixtures of the hybrid and parent were compared in the case of two different hybrids. Open-pollinated controls were included in the trial, which was sown at about the normal rate for beans. With both hybrids a mixture of 11 of hybrid to 1 of parent yielded as well as the hybrid itself and mixtures of 2 of hybrid to 1 of parent yielded in both cases about 7 cwt./acro more than the mean of the open-pollinated controls. With the higher-yielding hybrid, which had less contrast in vegetative vigour between hybrid and parent, mixtures in the proportions 5:1 and 2:1 showed declining yields, but with the other hybrid they yielded as well as the pure hybrid.


2021 ◽  
Author(s):  
Giuliano Cerasa ◽  
Gabriella Lo Verde

AbstractOzognathus cornutus (LeConte, 1859) (Coleoptera: Ptinidae: Ernobiinae), species native to North America, is a saproxylophagous species and is known to feed on decaying tissues within conspicuous galls and on vegetal decaying organic material such as dried fruits or small wood shavings and insect excrements in galleries made by other woodboring species. A few years after the first record in 2011, its naturalization in Italy is here reported. The insect was found as successor in galls of Psectrosema tamaricis (Diptera Cecidomyiidae), Plagiotrochus gallaeramulorum, Andricus multiplicatus and Synophrus politus (Hymenoptera Cynipidae). The galls seem to have played an important ecological role in speeding up the naturalization process. The lowest proportion of galls used by O. cornutus was recorded for P. tamaricis (23%), the only host belonging to Cecidomyiidae, while the percentages recorded for the other host species, all Cynipidae forming galls on oaks, were higher: 43.6%, 61.1% and 76.9% in A multiplicatus, S. politus and P. gallaeramulorum, respectively. Although O. cornutus is able to exploit other substrates like dried fruits and vegetables, for which it could represent a potential pest, it prefers to live as a successor in woody and conspicuous galls, which thus can represent a sort of natural barrier limiting the possible damages to other substrates.


1992 ◽  
Vol 6 ◽  
pp. 305-305
Author(s):  
Mahito Watabe

The late Miocene Chinese hipparions are morphologically diversified showing similarity to both western Old World's and North American forms. Two Chinese taxa that are phylogenetically related to western Old World's forms are Hipparion fossatum (= H. forstende) from Baode (Shanxi) and H. hippidiodus from Qingyang (Gansu) and Baode. The former is related to H. mediterraneum and the latter to H. urmiense - platygenys from the Turolian localities in the western Old World. H. fossatum and H. hippidiodus are associated with the “dorcadoides” (open-land) and “mixed” faunas in northern China. Hipparion fossatum that is characterized by POF located close to the orbit co-occurs with large and morphologically specialized form, H. dermatorhinum in Baode (Loc.30). H. hippidiodus with reduced POF is discovered with smaller H. coelophyes in Loc. 43, 44 (Baode) and Loc. 115 (Gansu).The hipparions associated with the “gaudryi” (forest) fauna are characterized by well defined and small POF located far from the orbit. Those forms are: H. platyodus from Loc. 70; H. ptychodus from Loc. 73; H. tylodus from Hsi-Liang in Yushe - Wuxiang basins; and H. sefvei from Loc. 12 at Xin-an in Henan province. H. coelophyes from Baode (Loc.43 & 44) and Qingyang (Loc. 115) also show similar facial morphology to the these forms, although it has small size and shallow POF. Those forms are similar in facial and dental morphology to Hipparion sensu stricto and some species of Cormohipparion in North America.The assemblages of Chinese hipparions are composed of two groups whose members are phylogenetically similar to the forms from both western part of Eurasia and North America. The “gaudryi” fauna is considered younger than the other two on the basis of faunal analyses. The similarity in hipparionine taxonomy between northern China and North America in the latest Miocene is an evidences for possible faunal interchange(s) occurred during that period, as suggested by taxonomic analyses on carnivores and proboscideans in eastern half of Eurasia and North America.


1987 ◽  
Vol 58 (4) ◽  
pp. 119-124 ◽  
Author(s):  
Gail M. Atkinson ◽  
David M. Boore

Abstract A stochastic model of ground motion has been used as a basis for comparison of data and theoretically-predicted relations between mN (commonly denoted by mbLg) and moment magnitude for eastern North America (ENA) earthquakes. mN magnitudes are recomputed for several historical ENA earthquakes, to ensure consistency of definition and provide a meaningful data set. We show that by itself the magnitude relation cannot be used as a discriminant between two specific spectral scaling relations, one with constant stress and the other with stress increasing with seismic moment, that have been proposed for ENA earthquakes.


1980 ◽  
Vol 112 (S112) ◽  
pp. 1-92 ◽  
Author(s):  
D.D. Munroe ◽  
Ray F. Smith

AbstractThe systematics of Acalymma sensu stricto of North America including Mexico are revised. Acalymma sensu stricto is defined and distinguished from the other species groups of Acalymma. Sixteen species are discussed including four new species: A. blomorum, A. palomarense, A. invenustum, and A. luridifrons all from Mexico. Three new subspecies of A. blandulum (LeConte) are described: blandulum (LeConte) new status, nigriventre, and yucatanense. Acalymma coruscum costaricense Bechyné is placed as a synonym of A. innubum (Fabricius). Keys are presented to all species and subspecies. Habitus and male genitalia drawings are given for all species and distribution maps are given where appropriate.


2017 ◽  
Vol 52 (7) ◽  
pp. 530-538 ◽  
Author(s):  
Luiz Paulo de Carvalho ◽  
Josiane Isabela da Silva Rodrigues ◽  
Francisco José Correia Farias

Abstract: The objective of this work was to evaluate the oil content and characters related to fiber quality and yield in cotton lines (Gossypium hirsutum), in order to select genotypes with high oil content and acceptable levels of the other characters. Twenty-two F6 lines and three checks were cultivated in three field trials - two in the municipality of Apodi, in the state of Rio Grande do Norte, and one in the municipality of Barbalha, in the state of Ceará, both in Brazil. The genetic parameters and the genetic gain from selecting 20% of the lines were estimated according to their means in each environment and in the group of environments. Regarding oil content, there is genetic variability, and the selection based on the overall mean is indicated, since this character showed high heritability, with 4.58% expected gain. The lines selected with this criterion have oil contents between 23.52 and 24.51%, which are higher than those of the Brazilian cultivar BRS Aroeira with the highest grain oil content (22.04%).


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