The causal sequence of meiosis
• . i . • pro6eeds"., and where crossing-over takes place. These prime wriables ..at6 ghe.eontaet-point, the th~e-lhnit of pairing and. the torsion in paired regions. Their action has been inferred from the comparison of pairing in ~dated forms witt{ variabie pairmg frequencies and ohiasma distribution ; from ~he pa.h-ing in hybrids, mutants and po]yploids; and h'om the ~ifieiaI !n}errnption of normal pairing. Suc]a comparisons have to be m~de ~vifla even ~ea te r accuracy and detgii if gee theory of meiotic p~mng.as to be ~ested and consolidated. The time has now arrived for an exac$ definitio~ of the individual aoti.ons and of the interactions of the t~{'egva.riables and of {Heir effect onohiasma formatim.~. k it}~iJ.y of pagfing variM;ion rest~Ith~g from genetic aad :from en~dr0nmental Souzces, i o an interspeeitie eo.mparison wibh varied environmental eoi~Ntigns,i.forms ~ahe most promising approach. ~,r,gt~igcvria., which h.a,s proved such Useful material in the discovery of ~he ele.me~lts o:[ mitosis and . . . . meiosis, is eminent.]y st~ita, ble :for further ana.].gsis} :[or the following rea.soJ.is:
The causal sequence of meiosis
6. Summary1. The frequency of chiasmata and of univalents is similar in pollen and embryo sac mother cells ofLilium testaceum.2. Cells with fewest chiasmata have those chiasmata most strongly localized either proximally or distally.3. Hence pairing must have begun either near the centromere or near an end. The contact point is optional.4.M chromosomes come into contact more readily near the ends,S chromosomes near the centromere.5. ButM chromosomes pair more slowly, so that the frequency of their chiasmata falls away more rapidly in low chiasma cells than that ofS’s.6. Samples of cells used for the study of meiosis in species and crosses must therefore be regarded as representing cross-sections of the process of pairing secured by a variable interruption of the process. Statistical treatment can be used to indicate the order of pairing and the means of interruption.
Mite population density analysis of stored dried apricots in Turkey
The aim of this study was to determine the population density of mite species attacking stored dried apricots in Malatya, Elazig and Izmir regions of Turkey. Storage construction types and duration of storage were also considered. The samples were collected during 2000–2003 in the most important apricot producing areas (Malatya and Elazig) and the exporting center (Izmir). Frequency of occurrence and rates of intensity of infestations were determined (16.50% from Malatya, 3.19% from Elazig and 80.49% from Izmir). A total of 16 mite species belonging to 13 genera and 11 families were identified during the surveys. The pest species Carpoglyphus lactis (L.) (Astigmata: Carpoglyphidae) was the most abundant species recorded (69.14% of samples). The highest infestation value recorded was 15,534 mites per kg.