ACTA AGRONOMICA TOMUS 12. (A MTA AGRÁRTUDOMÁNYI KÖZLEMÉNYEI, 1963)

1963 / 1-2. szám - L. MAGASSY: Selective Fertilization in Beet (Beta vulgaris L.)

4 L. MAGASSY multigerm population. In some cases hybridization was found to be varying from 3 to 28%. From crosses effected between sugar-beet varieties and mangel, PET­RUNYA [30] concluded selective fertilization to vary with the beet variety used. The percentage of hybridization was larger in sugar-beet. The percentage of hybrids obtained by artificial crossing was seen to vary with the amount of pollen and with time delay in the transfer to the stigma of the pollen from each component taking part in the pollination. From open pollination between sugar-beet and mangel, MEDVEDEVA [28] obtained a somewhat larger number of hybrid plants in sugar-beet. Crossings effected artificially yielded the same results. Investigations carried out by ZAYKOVSKAYA [44] have shown the pollen of the sugar-beet variety M6 to germinate more readily than that of the variety VI69I, both on artificial media, and under natural conditions. When mangel and garden beet Avere pollinated with pollen from the above two beets, a more numerous offspring was obtained in all cases from the variety M6 rich in sugar content, than from the highly yielding VI691. The pollen of the varieties with high sugar percentage proved more viable in pollen mixtures than that of the varieties with high yield. ZOSSIMOVITCH [45] suggests the possibilities offered by selective fertiliz­ation to be utilized in hcterosis-breeding. FÜRSTE [16] thinks it possible to utilize selective fertilization in poly­ploid beet-breeding Avith a view to increasing the production of triploid hybrids. In progenies derived from crosses between diploid and tetraploid sugar-beets he observed the ratio of triploid plants to vary from 25 to 92%. MAGASSY [25] reports data on the intravarietal variability of selective fertilization, on the possibilities of utilizing it in the heterosis-breeding of beet and briefly discusses the role of selective fertilization in breeding [12, 26]. Possible forms of selective fertilization in beet When on crossing variety A with variety В fertilization takes place without selectiv ity asserting itself P A X В Fl AA + AB + BA + BB 25% 25% 25% 25% 50% the ratio of the progenies will be that expected on the basis of probability, i.e. 50% hybrid and 50% selfed plants. In Table 1 the possible forms of selective fertilization in beet are condens­ed. This set-up is of universal validity for reciprocal crosses, irrespective of the

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