S U M M A K ^•The wild and cultivated forms ni'Daiictis carotn L. are andromonoeciou.s and protandrous. The separation otniale and female phases is complete at the level of the Hower and the umbel, but the two phases overlap at the level of the full plant, creating conditions for geitonosamy. .'^t the same time, insect visits between umbels of adjacent plants lead to xenogamy. The extent of overlap between the male and female phases of various umbel orders varies between wild and cultivated carrot. Consequently, there is probably more outbreeding in wild carrot. The chiasma frec^uency is higher in cultivated carrot. These findings indicate that the nieiotic system generates more variability in cultivated carrot whereas the breeding system has the potential to generate greater variability in the wild plant.Key words: Datictis carotn, breeding system, meiotic system, geitonogamy, protandry.In order to strike a balance betvveeti the imtnediate advantage of genetic confortnity (Stebbitis, 19.S0) and tbe long term advatitagc of genetic recombination, tbe reproductive system bas assLitned various kinds of morphological and pbysiological specialities in diflerent plants. Members of tbe cosmopolitan family, Apiaceae, ba\e more or less uniform fioral structure, yet tbey displa>' varied breeding systems (Hell, 1971). Tn view of tbe paucity of informatioti as to bow this is acbieved (Braak & Kho, 1958; Bell, 1971; Lloyd, 1973; Webb, 1979; Lindsey, 1982) vye investigated tbe reproductive mechanisms of the Himalayan representatives of tbe family. This study of wild and cultivated carrot was undertaken witb a view to determining vvbetber domestication bas imposed anv' cbanges in tbe reproductive system ot tbe speices. Flowering and pbenological events of different umbel orders and flowers were recorded from plants tagged for tbis purpose. .Antber debiscence and stigma receptivity were studied at regular intervals; the receptivity was determined frotn stigmas, of different ages, fixed in acetic alcohol (1 :3), stained witb aniline blue and mounted in lactopbenol. Stigmas bearing germinating pollen on tbeir surface were treated as receptive.
MATERIALS AND MET MODSTbe proportion of hermaphrodite and statninate flowers was determined per plant and per utnbel order by dividing the frequency of hermaphrodite flowers witb tbat of the staminate flowers.Pollen counts were made by calculating tbe number of pollen grains produced per anther. Tbese figures were employed for determining tbe total pollen production and calculating pollen-ovule ratios per Hower and per plant.For cytological inv estigations, seeds were collected from several individuals of eacb subspecies and germinated on moist filter paper placed in petri disbes maintained at room temperature. Root tips were e.xcised, wasbed and pretreated with ()-()03 M aqueous solution of 8-bydroxy-quinoline for 4-5 b at 5 °C. Tbereafter, tbe tips were fixed in acetic alcohol (1:3) for 24 h and stored in 70",, alcobol at 4 6 °C. In makitig cbromosome preparations, the root tips were b...
