Cytogenetical Studies in the Inbred Lines of Radish (<i>Raphanus sativus</i> L. var. <i>radicola</i> Pers.) and Their Hybrids

Genetic regulation of chromocentres in radish, Raphanus sativus L.

“…Ealier studies demonstrated that the amount and the distribution of con stitutive heterochromatin in radish, as inferred from the chromocentre counts in the interphase nuclei, are under the control of the genotype and related with homo and heterozygosity. Homozygotes have a higher number and wider distribution than the heterozygotes (Dayal 1975, Dayal et al 1981. The varietal populations of radish may be modelled for studying the genetics of heterochromatin.…”

Cytogenetical studies in the inbred lines of radish (Raphanus sativus L. var. radicola Pers.) and their hybrids. III. Meiotic abnormalities.

“…Inbreeding, as it is known, leads to gene unbalance which, in turn, inhibits proper functioning of chromosome pairing and exchange. It leads to decrease in chiasma frequency (Lamm 1936, Muntzing and Akdik 1948, Rees 1955, Zecevic 1961, Dayal 1977a. Along with the decreasing chiasma frequency there emerges with inbreeding an increasing number of structural and other abnormalities of chromosomes and the aberrant types of chromosome behaviour.…”

“…Materials and methods used in the present study are essentially the same as in the previous report (Dayal 1977a). Meiotic abnormalities at metaphase I and ana phase I along with other cytological characteristics were studied.…”

Inbreeding depression in chromosome behaviour of the garden cress (Lepidium sativum L.)

“…A. R. I., New Delhi and from Ludhiana respectively and were late sowing. Self ing was done as described earlier for radish (Dayal 1974-75). Seeds of the first (I1) and the second (I2) inbred generations were sown simultaneously in identical field condition.…”

“…Chromosome behaviour during meiosis has been studied on several occassions in the inbred lines of rye (Lamm 1936, Muntzing and Akdik 1948, Rees 1955a, maize (Blanco 1949, Konstantinov 1971, Zecevic 1960 and radish (Dayal 1977a(Dayal , b, 1979. The present report deals with the study of chromosome behaviour during meiosis in four cultivars of the garden cress and their inbred families (I1-I2) in order to see whether inbreeding affects the chromosome behaviour.…”