Production of healthy seed cane at the Estación Experimental Obispo Colombres (Tucumán, Argentina)

NOGUERA, A.S.; PAZ, N. DEL V.; DÍAZ, M.E.; PERERA, M.F.; DÍAZ ROMERO, C.; GARCÍA, M.B.; FILIPPONE, M.P.; CUENYA M.I. Y CASTAGNARO A.P

Workshop; 10th Germplasm and Breeding and 7th Molecular Biology Workshop. ISSCT; 2011

Since 2001, Estación Experimental Agroindustrial Obispo Colombres (EEAOC) has been working on ?Vitroplantas Project?. On average, 55,000 sugarcane seedlings of commercial sugarcane varieties are produced annually through in vitro meristem culture at the lab stage. The micropropagation technique is widely used to eliminate systemic diseases, especially viral ones. Hence, this project guarantees health and genetic purity of seedlings. The project involves the stages presented in this work. Sanitation of plant material is achieved through in vitro culture of apical meristems from donor plants, hydro-heat-treated previously and held for 3 years under greenhouse conditions with an anti-aphid screen. Also, systemic diseases are evaluated in both meristem donor plants and micropropagated seedlings by molecular diagnosis, a sensitive, rapid and reproducible choice. PCR protocols to detect two bacterial diseases, ratoon stunting and leaf scald, and RT-PCR protocols to detect SCMV and SrMV (causal agents of sugarcane mosaic disease) and ScYLS (causal agent of yellow leaf syndrome) are routinely applied. On the other hand, plant tissue in vitro culture can produce somaclonal variation, which consists of genetic modifications in cultured cells and tissues. Thus, a molecular methodology based on molecular markers to quantify and detect somaclonal variation in the propagation scheme is routinely applied as a complement of phenotypic evaluation in the field. In cases where this variation occurs, it is possible to detect it before releasing the material thus propagated. The seedlings produced in the lab undergo an acclimatization process in a greenhouse of EEAOC Sugarcane Breeding Program. In order to avoid dehydration, this process takes place in an environment with high relative humidity (RH = 80 - 100%) and low light intensity during the first two weeks. After that, RH is gradually reduced and the intensity of light gradually increased. Under these conditions, this critical stage that defines the commercial viability of the whole process lasts 90 days on average. Then, the material goes through two more stages of conventional propagation in the field (Basic and Registered Nurseries) before being distributed among sugarcane growers. Regarding productivity, efficiency and safety, propagated plants from meristems are quite advantageous. In effect in the short term, old and/or infected materials will be replaced with this healthy material of high yield potential in Tucumán, Argentina. This state-of-the-art technology, which is widely spread in sugarcane growing countries, has been incorporated by EEAOC to obtain healthy seedlings for release among local growers.