The objective of this work was to analyze the growth of three cultivars of Panicum maximum: Mombaça, Tanzânia and Vencedor grown in pots, under a transparent plastic cover. The pots were filled with 6 dm³ of redyellow latossol, clayish texture, with high organic matter content. The soil, after sifted, was limed and enriched with N and P, 150 mg/dm³ of each element. The seeds were seeded in the pots, in a total of 54. After thinning, five seedlings were left per pot. The pots were daily watered and fortnightly fertilized, each one, with 50 mg/dm³ N and K, in aqueous solution. Each cultivar was harvested at the ages of 17, 24, 31, 38, 44 and 52 days after seedlings emergence. There were three replicates for each cultivar and age. In each harvest, the plants were clipped close to the soil surface, and separated into: leaf blades, stem, root system and dead material. The leaf blade area was measured with a digital area meter system. The leaf blade, stem, and root system were weighed after drying at 60ºC for 72 hours. Instantaneous values were estimated for the growth indices: specific leaf area (SLA), leaf weight ratio (LWR), leaf area ratio (LAR), net assimilation rate (NAR) and relative growth rate (RGR), of all cultivars. There were differences among cultivars as for the instantaneous values of LAR and RGR at the age of 17 days. Variations of the SLA were the mainly causes in the changes in the LAR. No difference was observed among cultivars for NAR.
leaf area ratio; leaf weight ratio; net assimilation rate; relative growth rate; specific leaf area
