Inheritance of Tuber Greening Under Light Exposure in Diploid Potatoes

American Journal of Potato Research, May/Jun 2006 by Jakuczun, Henryka, Zimnoch-Guzowska, Ewa

RESULTS

Influence of Years, Families and Tuber Treatments on Tuber Greening

Analysis of variance on the parents and standards cultivars showed there was no significant year, tuber treatment, or year x tuber treatment interaction effects for either external or depth of tuber greening (Table 2), although for some genotypes significant variability of greening between years was observed. Correlation coefficients (r) between years for parents and standard cultivars were highly significant for both external and depth of tuber greening under all three storage conditions. Correlation coefficients were 0.93**, 0.55**, and 1.0** for external greening and 0.75**, 0.68**, and 0.68** for depth of greening following storage at 3 months at 10 C, 5 months at 4 C, and after reconditioning after 5 months at 4 C, respectively (Table 3).

Analysis of variance indicated a significant effect of families, years, and the interactions of families, treatments, and years, for external tuber greening in the 17 unselected families, while all the effects and interactions (except families x treatments) were significant for depth of greening (Table 4). Generally, both external and depth of tuber greening were greater in 1995, the first year, than in 1996, the second year (Tables 5, 6). For external tuber greening such significant differences were observed in eight families after treatment A, 11 families after treatment B, and two families after treatment C. In none of the families was external tuber greening significantly greater in the second year than in the first year. Significantly greater tuber-greening depths were found in the first year than in second year of evaluation in eight families after treatment A, three families after treatment B, and six families after treatment C. In treatment C tuber-greening depth was significantly greater in the second year of testing in four families. In general, correlation coefficients between the two years of testing within families for both elements of greening were significant but rather low to moderate (Table 3).

External tuber greening ranged from O to 5 in all families except one in 1995. Family mean of external tuber greening did not differ significantly from the mid-parent value in any of the families under treatments A and C, and was significant in only one family under treatment B. Two-year mean external greening in the ESG x EWG families was significantly lower than in the ESG x ESG families for all the treatments (Table 7). In addition, ESG x EWG families had significantly less external greening than EMG x ESG families under treatment A. EMG x ESG families had significantly less greening than ESG x ESG families under treatment C.

Likewise, depth of tuber greening ranged from O to 5 in all families except one in 1995. Family mean of depth of greening did not differ from mid-parent value in any of the families under any treatment. Two-year means of depth of greening was similar under all treatments for the DMG x DWG, DSG x DWG and DMG x DMG families (Table 7). In DMG x DWG families, depth of greening was significantly less than in DMG x DSG families under all treatments. In addition, in DSG x DWG and DMG x DMG families, depth of greening was less than in DMG x DSG families under treatment B and C.