بررسي تاثير تراكم بوته بر شاخص هاي فيزيولوژيكي و عملكرد علوفه هيبريدهاي مختلف سورگوم و يك رقم سودانگراس

Effects of plant density on physiological indices and forage yield of sorghum hybrids and a sudangrass cultivar

Precise understanding of physiological processes controlling the yield lead to increased crop yield potential. In order to evaluate the effects of different plant densities; growth; fresh and dry weight of sorghum hybrids and a sudangass cultivar, an experiment was conducted in a factorial design in completely randomized block with four replications in research farm of Torbat-j m at Islamic Azad University during 1998-99. Treatments were plant densities (25, 35 and 45 plant m- ) and two sorghum hybrids (Jambo, Speedfeed), a sorghum landrace, and a sudangrass cultivar. Results showed that plant densities had no significant effect on fresh and dry weight. However Duncanʹs multiple range test showed that 35 plants per m2 had higher yields and produced 80.94 and 37.63 ton ha. fresh and dry weight, respectively. Speedfeed had better morphological and physiological characteristics and produced the highest fresh and dry yield by 93.4 and 43.38 ton ha^-1, respectively. However, speedfeed was ranged with Jambo in one group. Total dry matter increased after 210 days after planting in all cultivars and then decreased which curve slope in landraces, sudangrass was lower than other cultivears. The highest relative growth rate (RGR) was observed 130 days after planting and was reducing during growth season. Speedfeed showd higher RGR than other cultivars in all growth stages but final stage.