INVESTIGADORES
CASTAGNARO atilio pedro
congresos y reuniones científicas
Título:
VALIDATION OF THE EFFECTIVENESS OF AN EMASCULATION TREATMENT IN SUGARCANE BY USING MOLECULAR MARKERS
Autor/es:
M. F. PERERA*, M. B. GARCÍA**, C. DÍAZ ROMERO**, M. I. CUENYA**, M. P. FILIPPONE*, AND A. P. CASTAGNARO
Reunión:
Congreso; ISSCT CONGRESS; 2013
Resumen:
Sugarcane cultivars are developed by means of three procedures: assembling a described population of parental clones; generating variable progenies by cross-pollination and selecting outstanding clones. Parents used in crosses are classified as male or female based on the relative amounts of viable pollen produced. High pollen production determined by both genotype and environmental conditions reduces ?female inflorescence? availability and restricts the possibility of cross combinations. However, male parents could be employed as female parents when an efficient emasculation treatment is used. This technique implies pollen sterilization by immersion of the panicle in hot or cold water, chemical products or steam. On the other hand, an ideal approach for hybridity testing is the use of molecular markers, especially SSR. To determine the effectiveness of an emasculation treatment (immersion of the panicle in water at 50ºC for 5 minutes), six cross combinations between two varieties commonly used as males, LCP85-384 and RA87-3, were evaluated by using SSRs. After the emasculation treatment, pollen absence in the two varieties was confirmed with a magnifying glass, whereas pollen was detected in the same varieties without treatment. The crosses were performed successfully and no viable seeds were obtained when LCP85-384 and RA87-3 were emasculated and selfed, respectively. Fifteen SSR primer pairs were evaluated so as to choose the one that produces an appropriate molecular profile in the two varieties. DNA of the progeny of each cross combination was screened with the primer that best differentiated the parents (MSCIIR19, unpublished sequence, D´Hont 2005), and the presence or absence of the specific markers was scored. This primer produced seven polymorphic and three monomorphic bands between the two progenitors. Segregation analysis showed that each marker segregated in a Mendelian fashion (as evaluated by χ2 tests, P≤0.05) for each cross combination. Results indicated that the treatment was successful to emasculate RA87-3 and LCP85-384 varieties completely and it did not cause a serious reduction in both the stigma and ovary viability. Also, this method is simpler, faster and cheaper than other emasculation techniques and it will allow the expansion of bi-parental crosses. Besides, the SSR technique allowed assessing the fidelity of sugarcane crosses. Thus, both implemented tools will improve crossing efficiency of sugarcane breeding programs.