Resumo

GARCIA, María B. et al. Effects of seedcane quality on yielding components of CP 65-357 and LCP 85-384 (Saccharum spp.) varieties at different crop ages (Part 2). Rev. ind. agric. Tucumán [online]. 2011, vol.88, n.2, pp.13-19. ISSN 1851-3018.

In Tucumán, most sugarcane producers have traditionally used seed cane from commercial plots infected with RSD (ratoon stunting disease) for their plantations. This systemic disease, caused by Leifsonia xyli subsp. xyli, is widely recognized for its detrimental effect on crop yield. A few years ago, the widespread availability of healthy seed caused fundamental changes in cultural practices that could lead to an increase in sugarcane productivity. This study aimed to quantify seed quality effect on crop yield and its components in two commercial varieties, LCP 85-384 and CP 65-357, through six crop ages. This study complements already published information on the previous three crop ages. The effects of using two seed cane types, namely high quality seed cane (SAC) obtained through in vitro micropropagation and commercial seed cane (SC) infested with RSD, were evaluated. The treatments were planted in a randomized complete block design with six replications. At each age, the following variables were evaluated: number of stalks/plot and stalk weight, height and diameter. Analysis of variance and mean comparison tests (Fisher DMS) were made. It was determined that seed quality affected yield components, inasmuch as high quality seed cane led to major stalk weight and height values and, to a lesser extent, higher stalk number. Stalk diameter was not affected by seed quality. At each age, there was a significant decrease in cane/ha production in SC treatments as compared with SAC treatments. Considering accumulated production through the six crop ages considered (plant cane to fifth ratoon), SAC treatments yielded 134 t cane/ha more in the case of LCP 85-384 and 93 t cane/ha more in the case of CP 65-357, as compared with SC treatments. These values reflect the benefits of using high quality seed cane in plantations.

Palavras-chave : Micropropagation; Healthy seed; Ratoon stunting disease; Yield decrease.

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