Solanum curtilobum Juz. & Bukasov

OVCHINNIKOVA, ANNA, KRYLOVA, EKATERINA, GAVRILENKO, TATJANA, SMEKALOVA, TAMARA, ZHUK, MIKHAIL, KNAPP, SANDRA & SPOONER, DAVID M., 2011, Taxonomy of cultivated potatoes (Solanum section Petota: Solanaceae), Botanical Journal of the Linnean Society 165 (2), pp. 107-155 : 117-119

2. Solanum curtilobum Juz. & Bukasov ,

Trudy Vsesoyuzn. S”ezda Gen. Selekts. Semenov. Plemen. Zhivotnov.3: 609. 1929.

Type: cultivated in Leningrad from tuber accession collected in Bolivia (La Paz, S. Juzepczuk 1707), viii.1929, S. Juzepczuk [1707] [lectotype, LE!, designated by Hawkes & Hjerting, 1989: 403 (confirmed by Ovchinnikova et al., 2009: 584, but no isotype in WIR found)]. Figure 2 .

Description: Herbs 0.5–0.9 m tall, semi-rosette when young, developing to semi-erect. Stems 10–16 mm in diameter at base of plant, with narrow wings, sparsely pubescent, green splotched with purple. Sympodial units tri- to plurifoliate, not geminate. Leaves oddpinnate, the blades 7–18 x 3.5–9.0 cm, dark green, membranous to chartaceous, sparsely pubescent adaxially and abaxially, with hairs like those of the stems; lateral leaβet pairs five or six, decreasing in size from the apex to the base; most distal lateral leaβets 2.5–4.5 x 1.5–2.7 cm, ovate to elliptic, the apex shortly acuminate, the base truncate to rounded to cordate; terminal leaβet 2.7–4.5 x 1.5–2.7 cm, ovate to elliptic, the apex shortly acuminate, the base truncate to rounded to cordate; interjected leaβets four to six, sessile to short petiolulate, ovate to elliptic; petioles 2–4 cm, pubescent as the stems. Pseudostipules absent to minute, auriculate, pubescent with hairs like those of the stem. Inβorescences 5–11 cm, terminal with a subtending axillary bud, generally in distal half of the plant, usually forked, with 8–14 βowers, with all βowers apparently perfect, the axes pubescent with hairs like those of the stem; peduncle 7–8 cm long; pedicels 16–22 mm long in βower and fruit, spaced 1–10 mm apart, articulation indistinct or only slightly distinct, articulated high in the distal half. Flowers homostylous, pentamerous. Calyx 6.0– 8.5 mm long, the tube 1–2 mm, the lobes 4.0– 7.5 mm, elliptic lanceolate, abruptly narrowed at apex to short pointed acumens, the acumens 2.0– 3.5 mm long, with hairs like those of the stem. Corolla 3.5–5 cm in diameter, rotate, lilac–purple, the tube 1–2 mm long, the acumens 1–3 mm long, the corolla edges βat, not folded dorsally, glabrous abaxially, minutely puberulent adaxially, especially along the midribs, ciliate at the margins, especially at the tips of the corollas. Stamens with the filaments 1–2 mm long; anthers 5–6 mm long, lanceolate, connivent, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary glabrous; style 8.0– 9.5 mm x 1 mm, exceeding stamens by 3–4 mm, straight, papillose in the distal half; stigma capitate. Fruit a globose to ovoid berry, 2–3 cm in diameter, green to green tinged with purple when ripe, glabrous. Seeds from living specimens ovoid and c. 2 mm long, whitish to greenish in fresh condition and drying brownish, with a thick covering of ‘hair-like’ lateral walls of the testal cells that make the seeds mucilaginous when wet, green–white throughout; testal cells honeycomb-shaped when lateral walls removed by enzyme digestion. Chromosome number: 2 n = 5 x = 60 (Huamán 60, Herbarium of the International Potato Center, Lima, Peru).

Phenology: Flowering and fruiting from January to May.

Distribution: Throughout the highlands of northern Peru to central Bolivia and rarely in northern Argentina, in cultivated fields, at elevations between 3600–4300 m.

Solanum curtilobum is of hybrid origin, resulting from a cross between S. juzepczukii Bukasov and tetraploid cultivars of S. tuberosum ( Hawkes, 1962; Schmiediche et al., 1980, 1982). In the CIP genebank are landraces mainly differentiated by the tuber skin colour and sprout colour. These have many different names, including ‘Shiri’, ‘Luki’, ‘Waña’, ‘Choquepito’, ‘Mallku’ and ‘Ococuri’, alone or in combination with names describing the tuber skin colour, such as ‘Yuracc’ or ‘Jancko’ (white), ‘Yana’, ‘Laram’ or ‘Azul’ (purple), or ‘Pinta’ (two-coloured) ( Huamán & Spooner, 2002).

Solanum curtilobum was first described by Juzepczuk & Bukasov in Volume III of the Proceedings of the USSR Congress of Genetics, Plant- and Animal Breeding held in Leningrad in January 1929 ( Juzepczuk & Bukasov, 1929), which was not available in the West. Therefore, in indices such as Index Kewensis (and, later, IPNI and the Gray Card Index), the place of first publication of this name and others coined in that 1929 publication was given as Bukasov’s (1930) treatment of the cultivated plants of Mexico, Guatemala and Colombia, in which the epithets validly described with Latin diagnoses previously were listed in the text, but not formally described. The use of S. curtilobum and other names (see S. tuberosum below) in Bukasov (1930) was clearly not intended as a new publication of these epithets.

Ovchinnikova et al. (2009: 584) confirmed Hawkes & Hjerting’s (1989: 403) lectotypification of S. curtilobum with a specimen in LE, but did not find the isotype cited by Hawkes & Hjerting as being in WIR; subsequent searches have also failed to reveal this specimen.

Figures

Figure 2. Lectotype specimen of Solanum curtilobum Juz. & Bukasov held in LE. Reproduced with permission of the V. L. Komarov Botanical Institute.