Resistance of some Soybean Genotypes to Bruchids: Callosobruchus chinensis L. as Influenced by Different Biochemical and Seed Quality Traits

Bruchids have high fecundity that cause damage to stored soybean; which leads to significant losses in yield. This study was aimed to assess the susceptibility of four soybean genotypes(H6 L58, Misr 6, Giza 22, and PI 416937)to bruchid (Callosobruchus chinensis L.) infestation. Different seed quality and biochemical tests were done on the genotypes including; moisture content (MC%), electrical conductivity (EC), content of total oil, crude protein, phenolic(TPC), additionally, seed coat thickness and germination % to measure their effect on the insect resistance parameters as; percent seed weight loss and Dobie susceptibility index(DSI), to C. chinensis. Soybean genotypes yield and its components were evaluated in the field as well. Although Misr 6 gave the highest seeds yield/plot (2.91 kg) and it was moderately resistant to insect infestation with6.35 DSI. The genotype PI 416937 recorded the highest MC% (15%) and its coat thickness was 6.6 μm, which helped to resist the C. chinensis infestation. Moreover, PI 416937 and Giza 22 recorded low EC 68.6 and 47.6 μScm-1g-1, which led to higher germination%(61.5% and 85%), respectively, than the others. Although there was no significant increase among the genotypes in TPC, it helped in resistance against the infestation. The TPC recorded a negative correlation with the F1 progeny traits for C. chinensis on soybean. Furthermore, the coat thickness and MC% have a significant negative correlation with the F1progeny traits. Taken together, the biochemical traits of seed quality and their contribution to soybean resistance to C. chinensis may be crucial for breeders to consider.