Morphological parameters of soybean plant resistance to lepidopterous defoliators

Abstract

Plants have defence approaches against various insect feeding strategies which include morphological (antixenosis), biochemical (antibiosis), and molecular (tolerance) mechanisms to offset the effects of herbivore attack. In this experiment the role of morphological characters to determine resistance-susceptibility of soybean (Glycine max L. Merril) genotypes were studied. Ten soybean varieties SL 979, RVS 2001–18, MACS 1340, KDS 708, JS 20–71, RKS 113, NRC 94, MACS 1394, NRC 93, CSB 904, were studied for correlation between field resistance and % infestation of insects viz., tobacco caterpillar (Spodopter litura), bihar hairy caterpillar (Spilosoma obliqa) and semi looper (Thysanoplusia orichalcea). A highly significant negative correlation was found between leaf hair density and per cent infestation for S. obliqua, S. litura and T. orichalcea. While, the other parameters viz., plant height, number of primary branches, nodes and pods were found to be nonsignificant. On the basis of correlation study it was concluded that varieties SL 979, RVS 2001–18, JS 2071 are comparatively more resistant having less infestation, while MACS 1340, MACS 1394 was most susceptible to all three mentioned insect-pests having more infestation.