EVALUATION OF AGRONOMIC CHARACTERS OF FORAGE SORGHUM CULTIVARS UNDER DIFFERENT THERMOPHOTOPERIODICAL CONDITIONS

Abstract

Some forage sorghum cultivars are sensitive to photoperiod, which causes variations in forage quality and yield when cultivated in different times of the year. To obtain further information on the sensitivity of sorghum to photoperiod and temperature, a trial was carried out to evaluate the sorghum cultivars AG 2002, BR 501, BR 506, BR 601, BR 602 and BR 700 (forages), AG 2005E and Massa 03 (dual purposes) and AG 2501C and BR 800 (cutting and grazing). These cultivars were sowed in eight times, at one-month intervals from October 1999 to May 2000. The experimental design was in randomized blocks with four replications, using the Scott-Knott test to compare sowing times and cultivars. The results allowed us to conclude that the flowering noninductive photoperiods (more than 12,9 h) caused high dry matter yields, plant height, node number and stem percentage in forage cultivars. The highest forage yields were obtained when sowing in October, November and December. In addition, there was an inverse relationship between head and leaf-stem percentage.

Keywords

• sorghum
• forage
• photoperiod
• temperature