Selection of full-sib families of Panicum maximum Jacq under low light conditions.

VICTOR, D. M.; JANK, L.; LEMPP, B.; SIMEÃO, R. M.; RESENDE, M. D. V. de; GONÇALVES, M. C.; DOUGLAS MOCHI VICTOR, EMATER-PR; LIANA JANK, CNPGC; BEATRIZ LEMPP; ROSANGELA MARIA SIMEAO RESENDE, CNPGC; MARCOS DEON VILELA DE RESENDE, CNPF; MANOEL CARLOS GONÇALVES, UFGD.

Selection of full-sib families of Panicum maximum Jacq under low light conditions.

2015

The silvopastoral system is a viable technological alternative to extensive cattle grazing, however, for it to be successful, forage grass genotypes adapted to reduced light need to be identified. The objective of this study was to select progenies of Panicum maximum tolerant to low light conditions for use in breeding programs and to study the genetic control and performance of some traits associated with shade tolerance. Six full-sib progenies were evaluated in full sun, 50% and 70% of light reduction in pots and subjected to cuttings. Progeny genotypic values (GV) increased with light reduction in relation to plant height (H) and specific leaf area (SLA). The traits total dry mass accumulation (DM) and leaf dry mass accumulation (LDM) had GV higher in 50% shade and intermediate in 70% shade. The GV of tiller number (TIL) and root dry mass accumulation (RDM) decreased with light reduction. The highest positive correlations were obtained for the traits H and RDM with SLA and DM; the highest negative, correlations were between TIL and SLA and RDM, and H and LDM. The progenies showed higher tolerance to 50% light reduction and, among them, two stood out and will be used in breeding programs. It was also found that it is not necessary to evaluate some traits under all light conditions. All traits had high broad sense heritability and high genotypic correlation between progenies in all light intensities. There is genetic difference among the progenies regarding the response to different light intensities, which will allow selection for shade tolerance.

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