Red Pearl: A New Gourmet Red Potato Variety

American Journal of Potato Research, May/Jun 2004 by Groza, H I, Bowen, B D, Kichefski, D, Peloquin, S J, Jiang, J

Electrophoretic Pattern of Tubers

The isozyme pattern of Red Pearl is Mdh- 1^sup 2^1^sup 2^1^sup 3^1^sup 4^, Mdh- 2^sup 2^2^sup 2^2^sup 2^2^sup 2^, Got- 2^sup 5^2^sup 5^2^sup 5^2^sup 5^, Got- 3^sup 3^3^sup 2^3^sup 4^3^sup 4^, Pgm- 1^sup 1^1^sup 2^1^sup 2^1^sup 3^, Pgm- 2^sup 2^2^sup 2^2^sup 2^2^sup 2^, Pgi- 1^sup 2^1^sup 2^1^sup 2^1^sup 2^, Prx- 3^sup 1^3^sup 1^3^sup 3^3^sup 2^, and 6-Pgdh- 3^sup 1^323^sup 2^3^sup 2^, where the normal script digit represents the locus and the superscript digit represents the allele for the enzymes malate dehydrogenase (Mdh), glutamate oxaloacetate transaminase (Got), phosphoglucomutase (Pgm), phosphoglucose isomerase (Pgi), peroxidase (Prx) and 6-phosphogluconic acid dehydrogenase (6-Pgdh), according to the procedure and nomenclature of Douches and Ludlam (1991).

CHARACTERISTICS

Red Pearl produces small tubers. Up to 70% of the tubers have a diameter smaller than 4.76 cm or 1 7/8 in. Tubers are round oval in shape and show an attractive dark red color with medium deep eyes (Figure 2). The tuber size and uniformity make Red Pearl an ideal potato for gourmet (creamers and steamers), canning and home gardens. Red Pearl has a low yield because of its small tuber size (Tables 1 and 2). The total yield of Red Pearl is 54-77% Red Norland in different years (Table 1). In the 1993 NCRT Red Pearl showed an average of 34.5% B size tubers in eight locations compared to 3.9% for Red Norland (Secor and Farnsworth 1994). Lamont and Simpson (1998) reported 56% B size tubers in Red Pearl compared to 14% in Dark Red Norland in Pennsylvania.

The red skin color of Red Pearl is darker than that of Dark Red Norland. Red Pearl tubers harvested in sandy soils after 3 wk from vinekilling show a good skin set and maintain a better color intensity in storage than Dark Red Norland. Some growth cracks were noted in the NCRT. However, Red Pearl showed less off-shape tubers than Dark Red Norland and Red Pontiac, no hollow heart nor internal necrosis as compared to 1.7% and 0.6%, respectively, for Dark Red Norland, and 5.3% and 5.0%, respectively, for Red Pontiac. The average vascular discoloration for Red Pearl was 2.3% compared to 8.7% for Dark Red Norland and 3.1% for Red Pontiac (Secor and Farnsworth 1994).

The specific gravity of Red Pearl is slightly higher than Red Norland (Table 3). The fry color was significantly better in Red Pearl (3.4 average in the scale of 1-10, where 1 is light and 10 is dark) than in Red Norland (4.0) and Red Pontiac (3.8) (Secor and Farnsworth 1994). The boil and bake quality of Red Pearl samples grown in Pennsylvania was found to be good (2.0) for Red Pearl compared to very good (1.5) for Dark Red Norland (Lamont and Simpson 1998). When boiled, the tubers of Red Pearl grown in Rhinelander, Wisconsin, had a less mealy texture and less flavor than Dark Red Norland after six month storage at 7.2 C. The sloughing of the boiled Red Pearl tubers was close to that of Dark Red Norland. Red Pearl tubers showed more discoloration than Dark Red Norland when assessed immediately after boiling (Table 4).