Simple PCR-based tolls provide molecular identification of the main rootstock used in Sao Paulo Stat

Distinguishing between 'Sunki' and 'Cleopatra' mandarins as well as between 'Carrizo' or 'Troyer' citrangesand 'Swingle' citrumelo very early in the nursery based only based on their respective leaf morphologycould result in erroneous interpretation. Horticultural advantages of 'Swingle' rootstock are incomparableto 'Carrizo' under our conditions (Sao Paulo State, Brazil). The crescent diversification of citrus rootstockvarieties in SP state has demanded, in particular situations, for identification of rootstock varieties very earlyin the nursery, sometimes as a consequence of accidental mixture of seeds. To help growers and nurserymanaccurately identify rootstock varieties, we developed PCR-based tools that identify most of rootstocks used inSP state. Information from three-selected RAPD 10mer primers (M04-ggcggttgtc, M15-ctggcgtgtc, and AB18-gacctaccac) can be successfully used to identify and genetically separate citrange, citrumelo, and Poncirustrifoliata. Another 10mer primer (R04-cccgtagcac) identifies 'Rangpur' lime (Citrus limonia) and separatesit from 'Volkameriano', and 'Siciliano' lemons. From the fingerprints generated by those 10-mer primers,repeatable and consistently well-amplified DNA fragments are used as variety-specific markers. Also, 'Sunki' and 'Cleopatra' mandarins are identified by the microsatellites CCSM-6R (cctctattaatgtgcctg) and CCSM-6F(atctgtgtgaggactgaa) primers. These simple PCR based protocols have been used to avoid significant economiclosses by the early and correct identification of rootstocks in SP state nurseries. Support: INCT Citros (CNPQ and FAPESP)