Journal or Publishing Institution: Növényvédelmi Tudományos Napok
Study: https://web.archive.org/save/http://bdarvas.hu/download/pdf/GenetE.pdf
Author(s): Fónagy, A., Krishnan, Muthukalingan, Bánáti, H., Lauber, E., Takács, E., Székács, A., Nyiri, A., Herman, G., Kugler, N. and Darvas, B.
Article Type: Report
Record ID: 699
Abstract: Hybridization among cultivars is a major issue among foreign pollinators during seed grain production. Our basic experiments were run modelling mass production, in parallel with studies for pollen competition. We followed flowering and productivity of 70–80 individual plants originating from different cultivars (Yellow DK-440, Yellow DK-440 BTY, Yellow Y, Yellow Y’, Yellow SU Zamora, Yellow X, Yellow X’, Blue, Red dentiform, Mindszenti white, Kiskun white), where the plot was framed by six rows as border lines. Pollen capturing rows of yellow varieties were sawn 40–120 m away from these plots. The plots were surrounded by grass meadows with dominating alfalfa. Flowering time of the cultivars under investigation may be subdivided into three groups: early (Blue and Mindszenti white), normal or mid (majority of varieties) and late (Kiskun white) pollinators, respectively. Tillering (pollination) followed this sequence. The appearance of silk and maturing of female flower modified this picture in case of SU Zamora, since it had to be aligned into the early flowering group. From flowering and fertility point of view the new hybrid varieties are much more uniform compared to traditional, regional cultivars (Blue, Red dentiform, Mindszenti white). All these circumstances allow a much broader range of pollination for the latter. Tillering (pollen emission) in general is 10–14 days long. Female flowering or receptivity may be characterized similarly, however, it should be noted that the highest chance for female fertilization is on the day following the appearance of respective silk. Cross pollination among all cultivars tested, due to the late flowering of Kiskun white, was rendered impossible. This also means, that if experiments are conducted without careful evaluation of characteristics of flowering/ tillering, few meters of isolation distance may be found appropriate. In the crossbreeding studies the gene for silk red colouration of Red dentiform is dominant, thus colour of grains was not altered by using blue, yellow or white origin pollen. On the other hand, the pollen did not carry red colour gene in a dominant way. The blue/lilac colour of the Blue variety is, however, inherited dominantly opposite to yellow or white varieties. Besides the uniform blue colour appearance of mosaics is also common due to transposon activity. Our cross-breeding experiments with MON 810 varieties resulted in well identifiable samples for further Cry1 toxin studies. The cry1 gene transferred via the pollen produces Cry1 toxin in the same year. We encountered 5–30% hybrid formation during grain formation, which finding may be validated for the isogenic GM maize border lines. Resistance management regarding cob pests due to the mixed nature of kernels containing Cry toxin is questionable, because based on selection pressure more successful survival is allowed. Therefore, for border lines, varieties with significantly different flowering time are suggested. Under free flowering conditions, when the dominant pollen source (blue) was very limited and was surrounded by six border lines, appearance of blue/lilac hybrid mosaic cobs was below 1% in maize 40–120 m away At the same time, as far as 500 m from the respective pollen source we found 5 blue kernels on a single cob. In our experiments next year – based on the above findings – we will investigate the seed grain production conditions (de-teaselling = male sterile techniques) excluding pollen competition.
Keywords: MON 810; blue maize; white maize; red maize; intraspecific hybrid; isolation; coexistence; Cry1 toxin
Citation: Fónagy, A., Krishnan, Muthukalingan, Bánáti, H., Lauber, E., Takács, E., Székács, A., Nyiri, A., Herman, G., Kugler, N. and Darvas, B., 2010. Flowering times of maize varieties in special respects for intraspecific hybridization (MON 810 x other varieties). Növényvédelmi Tudományos Napok, 56 : 53.
