Inheritance of Tuber Greening Under Light Exposure in Diploid Potatoes

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

In this experiment storage time and temperature have to be considered together as environmental factors. In general, external tuber greening slowly increased with prolonged tuber storage whereas depth of tuber greening decreased, and greening was greater for external in comparison to depth of tuber greening in all three treatments. External tuber greening differed significantly in ESG x EWG families between treatments A and C (Table 7). Depth of tuber greening differed significantly in all groups of families between treatments A and C, in DSG x DWG and DMG x DMG families between treatments A and B, and in DMG x DSG families between treatments B and C (Table 7).

Some of the progeny greened significantly less than their parents. For external greening, such progeny were noted in EMG x ESG and ESG x ESG families in all treatments. For depth of tuber greening such progeny were found in DMG x DSG, DMG x DMG and DMG x DWG families under all treatments. For external greening overall percentage of progeny which scored O was 3%, 7%, and 7% in treatments A, B, and C, respectively. For depth of greening overall percentage of progeny that scored O was 10%, 21%, and 25% in treatments A, B, and C, respectively. Progeny that scored O for external greening were observed in 14 out of 17 families and for depth of tuber greening in 16 out of 17 families.

Most of the correlation coefficients between external and depth of tuber greening for unselected families were significant; however, they varied considerably (Table 8). In few cases the correlation coefficients were insignificant. For all 1,229 progeny r ranged from 0.46 to 0.68 in 1995 and from 0.50 to 0.72 in 1996. Analogous correlation coefficients for the parents and standard cultivars were significant and varied from 0.75 to 0.80 in 1995 and from 0.77 to 0.88 in 1996 (Table 8).

Maternal Effect

Analyses of variance on three sets of reciprocal families revealed significant maternal effects on external tuber greening in only one set of reciprocal families under treatment B. The parents of these reciprocal families had strong and moderate tendency to greening. No maternal effects were found for depth of greening under any treatment.

General and Specific Combining Ability

Mean squares from the analysis of variance of 12 families in the NC design II indicated significant GCA and SCA effects for both external and depth of tuber greening (Table 9). There were significant differences between years for both types of greening under the three tested storage conditions with the exception of depth of tuber greening after treatment C. GCA of the males was significant for both types of greening under all treatments. GCA of the females for external tuber greening was significant under two storage treatments, but for depth of tuber greening GCA was only significant under treatment A. SCA was significant for both types of greening under all treatments. However, significant SCA effects for respective crosses were found sporadically. For external tuber greening, it was documented in three families under treatment A. For depth of tuber greening, it was found in one family under treatment A and B and in a second different family under treatment B. GCA x year interactions were significant for both types of tuber greening for females and for depth of greening for males, excluding treatment C. SCA x year interactions were significant in external and depth of tuber greening except for external greening under treatment C.