Identification of the ploidy structure of bud sport of Red Globe grape cultivar

CHEN Jun; TANG Xiao-ping; MA Xiao-he; ZHAO Qi-feng; LIANG Fu-qing

Abstract：Red Globe's bud sport is discovered in recent years from the vines of Red Globe grape cultivar. In order to identify its ploidy structure the size of stomatal guard cell and chloroplast number in these cells were measured and counted; the chromosome number of the root tip cell was also counted. The ploidy of L_Ⅰ, L_Ⅱ, L_Ⅲ in the sport and maternal cultivar were examined. Results showed that the stomatal guard cells of the sport (Red Globe' s bud sport) were a little longer than those of Red Globe and a little shorter in width. The chloroplast number in stomatal guard cells of the sport and Red Globe were 11.35 and 10.63 respectively. Both the size and chloroplast number of stomatal guard cells had no significant difference, therefore, it indicated that the pioidy of L_Ⅰ of the sport was diploid. The length of pollen grains in the sport and Red Globe was 35.46 and 33.03 μm respectively, and the width of pollen grains was 22.95 and 18.04 μm respectively. Both the length and width of pollen grains of the sport of Red Globe were significantly longer, so it was concluded that the ploidy of L_Ⅱ of the sport was te-traploid. The chromosome number in the root tip cell of sport was 2n=4x=76, while that of Red Globe was 2n=2x=38. There-fore it showed that the ploidy of L_Ⅲ of the sport of Red Globe was tetraploid. In addition, by observing the stem apex section, no significant difference was noted between the ceils of L_Ⅰ in Red Globe and its sport. Yet the cells of L_Ⅱ and L_Ⅲin the sport were obviously bigger than Red Globe. All of the above mentioned proved that the ploidy structure of Red Globe' s bud sport is a periclinal chimera(2-4-4).