J. Mozafari et al., CHROMOSOME DOUBLING VIA TUBER DISC CULTURE IN DIHAPLOID POTATO AS DETERMINED BY CONFOCAL MICROSCOPY, Plant cell reports, 16(5), 1997, pp. 329-333
The potential of tuber disc culture for chromosome doubling was invest
igated in somaclonal populations of four dihaploid genotypes and one t
etraploid cultivar of potato (Solanum tuberosum). Laser scanning confo
cal microscopy (LSCM) was used for rapid determination of the ploidy l
evel based on the number of chloroplasts in stomatal guard cells of le
aves. Factorial analysis of chloroplast number in 58 clones and two le
af types showed that somaclones were clearly divided in two groups. Cl
ones with 5-7 chloroplasts per cell as observed in tuber derived diplo
id controls were classified as 2X (not doubled), while those with 9-14
chloroplasts resembled the tuber derived tetraploid controls and were
considered 4X (doubled). A high frequency of spontaneous chromosome d
oubling, 42% - 50%, was detected in 3 dihaploid genotypes, whereas no
doubling was observed in one of the dihaploids as well as the tetraplo
id cultivar Yukon Gold. Effects of leaf type on chloroplast number was
also significant. The middle leaf showed significantly higher chlorop
last number than the younger leaves.