Soybean varietal tolerance to inter cropping with semi-dwarf grain sorghum

ABSTRACT

Two soybean [Glycine max [L. Merrill] varieties; viz. Clark-63 and Cuttler-71 were intercropped with the grain sorghum [Sorghum bicolor Moenc] variety Dorado in a 2 + 2 row intercropping pattern. Both soybean varieties and the grain sorghum variety were also separately planted with the solid recommended plant densities [Solid I] as well as in comparative treatments where the same plant densities were applied under intercropping [Solid II]. Sorghum grain yield per plant was increased by 47 and 35 percent from the comparative monoculture treatment yield due to the intercropping with Cuttler and Clark varieties respectively. On the other hand, soybean pod-set, seed yield per plant and seed index were reduced under intercropping, the reduction in these yield components was greater for Cuttler than for Clark variety. Land Equivalent Ratio [LER] values increased in efficiency by 17 and 7 percent when grain sorghum was intercropped with Clark and Cuttler varieties, respectively. The competitive Ratio [CR] values indicated that one grain sorghum plant was equivalent to 2.45 and 1.60 soybean plants of Cuttler and Clark varieties, respectively. Choice of a suitable soybean variety under this intercropping pattern may play an important role for increasing land equivalent ratio under conditions of the experiment