Abstract

SIMON, G; COLLAVINO, N; GRAY, L  and  MARIOTTI, J. Heredabilidad de la resistencia a la roya común (Puccinia melanocephala H. et P. Sydow) en familias FS de caña de azúcar (Saccharum spp). RIA. Rev. investig. agropecu. [online]. 2016, vol.42, n.1, pp.54-65. ISSN 1669-2314.

The genetics of cultivated sugar cane as crop is complex. Resistance to common rust (Puccinia melanocephala H. et P. Sydow) seems to have a poligenic or oligonenic genetic basis, showing mainly additive and interaction genetic effects. The use of resistant varietiies is accepted to be the best suited method for its control, which justifies research on acting genetic mechanisms. The aim of the research was to estimate heritability of resistance to common rust by means of the regression of hybrid progenies means on parents resistance means. Eight hybrid FS families (BIP) involving 11 parents with different degrees of resistance were investigated for three consecutive years at Barro Negro (Rio Grande Factory, Jujuy, Argentina). Joint regression across years estimated heritability as h2= 0.66 (determination 48%) with values of 0.90, 0.85 and 0.33 for years 1, 2 and 3, respectively. Differences among years are explained by variation of environmental components and probably also due to variation in the population genetic structure of P. melanocephala. Results indicate the predominance of additive genetic effects determining resistance, which explain 92% of total genetic variation. Heritability indicates the potential of parents to transmit resistance to their progenies, enabling the selection of appropiate hybrid combinations for increasing the frequency of resistant progenies. Results strongly indicate a polygenic nature of the genetic determination of common rust resistance in these materials. This type of resistance could be complemented with other reported mechanisms contributing to sustain the resistance.

Keywords : Saccharum; Rust; Puccinia melanocephala; Resistance; Heritability.

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