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421.
L.S. Boiteux J.R. Hyman I.C. Bach M.E.N. Fonseca W.C. Matthews P.A. Roberts P.W. Simon 《Euphytica》2004,136(1):37-44
In carrot, two codominant sequence-tagged site (STS) markers, flanking in tight linkage the Meloidogyne javanica resistance (Mj-1) locus, were employed to investigate the association between expression of resistance and locus dosage. Phenotypic expression
of homozygous resistant (R); heterozygous; and homozygous susceptible (S) individuals in an F2 population of 396 F2 plants from ‘Brasília-1252’ (R) × ‘B6274’ (S) was estimated for three resistance criteria: total egg production per plant
(TEP), egg production per gram of fibrous root (EPG) and root gall index (RGI). The homozygous resistant class had average
values of 403.9 for TEP; 147.5 for EPG and 0.8 for RGI. The heterozygous class had 1,673; 477.3; and 0.16 whereas the homozygous
susceptible class had 68,604; 11,877; and 2.54, respectively. The dominance ratio (d/a) indicated that genomic region(s) derived
from the resistant parent encompass genetic factor(s) with almost complete dominance for RGI (d/a = 0.93–0.94) and incomplete
dominance for transformed (TEP)0.25 and (EPG)0.25 (d/a = 0.63–0.65). Broad sense heritabilities were high varying from 72.9% for (EPG)0.25 to 86.0% for RGI. Narrow sense heritability values ranged from 55.9% for RGI to 64.3%for (TEP)0.25. Highly significant orthogonal contrasts were observed between homozygous resistant vs. heterozygous for (TEP)0.25 and (EPG)0.25. Marker-assisted selection could greatly facilitate the incorporation of the Mj-1 allele in both male-fertile and male-sterile counterpart lines in order to obtain F1 hybrids with the most effective levels of resistance.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
422.
The effects of continuous exposure of the adult and crawler stages of the whitefly, Trialeurodes vaporariorum, and adult of the parasitoids Encarsia formosa and Eretmocerus eremicus to spray deposits of potassium salts of a fatty acid and diafenthiuron applied at recommended rates were evaluated. French bean, Phaseolus vulgaris Prince, plants were sprayed and the adults confined on them using modified 5 cm Petri dishes. Fresh (4 - 5-h-old) deposits of fatty acids resulted in a 10.7% mortality rate of whitefly adults and 8.0 and 10.7% mortality rates of E. formosa and E. eremicus adults respectively, while fresh deposits of diafenthiuron resulted in a 62.7% mortality rate of whitefly adults and 12.0 and 14.7% mortality rates of E. formosa and E. eremicus respectively. The mortality rate (6.9 and 69.7%) of whitefly crawlers was recorded when exposed to 24-h-old deposits of fatty acids and diafenthiuron respectively. The mortality rate declined as the deposits aged. Adult parasitoid emergence from the treated pupae was unaffected. Spray deposits of diafenthiuron were effective against whitefly for up to 2-3 weeks in comparison with fatty acids, which were effective only when sprayed. Both products were harmless to adults as well as pupae of both parasitoids irrespective of the exposure period (age of deposits) tested (IOBC Class 1). These insecticides can be included in integrated pest management strategies against whitefly with the fatty acids used on horticultural crops. 相似文献
423.
microstigmus comes: sociality in a sphecid wasp 总被引:1,自引:0,他引:1
R W Matthews 《Science (New York, N.Y.)》1968,160(829):787-788
Pendent nests of the wasp Microstigmus comes from Costa Rica contained up to 18 adults each. Ovarian dissection indicates that there is reproductive dominance (division of labor) among females from the same nest, without apparent external morphological differences. Evidence for parental care and cooperation in provisioning and defense also identify this as the first social sphecid wasp. 相似文献
424.
West MA Wallin RP Matthews SP Svensson HG Zaru R Ljunggren HG Prescott AR Watts C 《Science (New York, N.Y.)》2004,305(5687):1153-1157
Microbial products are sensed through Toll-like receptors (TLRs) and trigger a program of dendritic cell (DC) maturation that enables DCs to activate T cells. Although an accepted hallmark of this response is eventual down-regulation of DC endocytic capacity, we show that TLR ligands first acutely stimulate antigen macropinocytosis, leading to enhanced presentation on class I and class II major histocompatibility complex molecules. Simultaneously, actin-rich podosomes disappear, which suggests a coordinated redeployment of actin to fuel endocytosis. These reciprocal changes are transient and require p38 and extracellular signal-regulated kinase activation. Thus, the DC actin cytoskeleton can be rapidly mobilized in response to innate immune stimuli to enhance antigen capture and presentation. 相似文献
425.
Proprioceptive illusions induced by muscle vibration: contribution by muscle spindles to perception? 总被引:16,自引:0,他引:16
When vibration of 100 hertz was applied to the tendon of the biceps or the triceps muscle, the subject made a systematic misjudgment of the angle at the elbow. During contraction the error could be as much as 40 degrees. The subject thought that the elbow was in the position that it would have assumed if the vibrated muscle had been stretched. 相似文献