ANALYSIS OF SEED SET UNDER INBREEDING AND OPEN POLLINATION IN VARIETIES AND LINES OF RADISH

Seed set in three radish varieties and 34 lines obtained from them by inbreeding were studied for six years (1968-1973). In radish varieties and lines, irregular variation in pod frequencies and the number of s eeds per pod under inbreeding and open pollination was observed. The v ariety Virovskii Belyi was stable in terms of the means of the charact ers under study from year to year. Out of two other varieties, Saxa an d Ledyanaya Sosul'ka, the first variety displayed temporal stability o nly for the number of seeds under open pollination. In Ledyanaya Sosul 'ka, pod frequencies and the number of seeds per pod may reach very hi gh values, comparable with those from cross-pollination. In groups of lines originating from three radish varieties, significant interline v ariation in all traits occurred; on the whole, in groups of lines, a h igh variability of the characters tested from year to year was observe d. The level of interline intragroup variability was virtually the sam e in all three groups. Mean pod frequency after selfing is constantly higher in lines derived from Virovskii Belyi than in the original vari ety; in some years, this tendency was observed in the Saxa variety; in Ledyanaya Sosul'ka, this trend was shown during the first three years of the survey, while during the last three years, the opposite situat ion occurred. After open pollination, mean pod frequencies and the num ber of seeds per pod were constantly lower in lines of all groups than in the corresponding parental varieties. The last two facts are expla ined by selection for a high level of self-fertility in lines after se lfing and by expression of inbred depression of the total fertility, r espectively.