Efficient slow-growth conservation and assessment of clonal fidelity of Ullucus tuberosus Caldas microshoots

Slow-growth is a biotechnological tool for medium-term conservation of plant germplasm under in vitro conditions.

In the present study, we assessed six culture media supplements and two cultivation temperatures to develop a reliable in vitro conservation protocol for ulluco (Ullucus tuberosus Caldas), an Andean tuber crop rich in carbohydrates and vitamin C. One-nodal segments of ulluco were cultivated on half-strength Murashige and Skoog (MS) medium supplemented with mannitol (10–30 g l⁻¹), sorbitol (10–30 g l⁻¹), sucrose (10–120 g l⁻¹), chlorcholinchlorid (CCC; 300–700 mg l⁻¹), abscisic acid (ABA; 1–3 mg l⁻¹), or maleic hydrazide (MH; 0.1–0.5 mg l⁻¹). In vitro cultures were maintained at either 5 °C or 17 °C cultivation temperature. After 18-month cultivation, based on growth characteristics, survival percentage and form of survival (plant, live shoot + microtuber, microtuber + dead shoot), four treatments were selected: 30 g l⁻¹ mannitol|17 °C, 30 g l⁻¹ sorbitol|17 °C, 0.3 mg l⁻¹ MH|17 °C and 60 g l⁻¹ sucrose|17 °C.

The plantlets from these treatments were tested for regrowth ability on half-strength MS medium. After 28 days of cultivation, survival percentage and morphological characteristics were evaluated. Plantlets originating from conservation medium supplemented with 30 g l⁻¹ mannitol showed the fastest regrowth and provided overall superior characteristics over shoots from other treatments. These plants were subjected to inter simple sequence repeat analysis, which gave rise to monomorphic patterns indicating no detected genetic variation between plants recovered after conservation on this medium and proving the reliability of this conservation protocol.

Hammond Hammond, S.D.; Viehmannova, I.; Zamecnik, J.; Panis, B.; Hlasna Cepkova, P.