CYTOGENETIC STUDY OF INTERSPECIFIC HYBRIDS BETWEEN VIRIS ROTUNDIFOLIA AND VITIS VINIFERA

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.

XXVI International Horticultural Congress: Viticulture – Living with Limitations

X. Xu, J. Lu

Grapevine, chromosome, fertility, mitosis, and meiosis

https://doi.org/10.17660/ActaHortic.2004.640.32