ISHS Acta Horticulturae 640: XXVI International Horticultural Congress: Viticulture - Living with Limitations
CYTOGENETIC STUDY OF INTERSPECIFIC HYBRIDS BETWEEN VIRIS ROTUNDIFOLIA AND VITIS VINIFERA |
| Authors: | X. Xu, J. Lu |
| Keywords: | Grapevine, chromosome, fertility, mitosis, and meiosis |
| Abstract:
Muscadine grape (Vitis rotundifolia Michx.) has a chromosome number of 2n = 40. European bunch grape (Vitis vinifera L.) has a chromosome number 2n = 38. With few exceptions, the chromosome number of hybrids between V. rotundifolia and V. vinifera is 2n = 39. As a result, the hybrids are either completely sterile or highly sterile with some fertility. To understand the variation of hybrid fertility, a study was conducted to investigate the chromosome number and pairings of the interspecific hybrids ‘Jumbo’ (V. rotundifolia) x ‘Thompson Seedless’ (V. vinifera) in mitosis and meiosis. Interspecific hybrids were obtained from crosses of muscadine grape (female) x V. vinifera (male) and from reciprocal crosses. Chromosome numbers of the hybrids used for this investigation were first confirmed by root tip cells (RTC) in mitosis. Most of them had a chromosome number 2n = 39. Several morphological characteristics also clearly indicated that they are true hybrids of V. rotundifolia x V. vinifera. Microscopy studies at meiosis of pollen mother cells (PMCs) showed a certain degree of chromosome pairing (bivalent) with some multivalent and monovalents. For those hybrids with 2n = 39, chromosome pairs ranged from 13 to 19. The result indicated that the low fertility of the hybrids is mainly due to the lack of chromosome pairings in their meiosis. | |
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