Modifying Controlled Deterioration for Evaluating Field Weathering Resistance of Soybean

Abstract

To develop practical methods for testing field weathering resistance of soybean varieties, pods and seeds from CM60 (susceptible) and GC10981 (resistant) were tested by seven treatments. Among the treatments, modified incubator weathering (yellow pods were incubated at 30°C under 90-100% relative humidity for 7 days) and the controlled deterioration (dry seeds were soaked in distilled water for 60 minutes and then incubated at 41°C under 90-100% relative humidity for 3 days) showed widerange differences in seed germination and viability between CM60 and GC10981. These two treatments were then tested on 11 soybean varieties comparing with a field weathering treatment. The germination of seeds treated by controlled deterioration was highly correlated to the germination of seeds subjected to field weathering treatment (r=0.964**, n=11). The viability of seeds submitted to both incubator weathering and controlled deterioration were also correlated to the viability of seeds exposed to field weathering (r=0.697* and 0.716*, n=11). The modified incubator weathering and controlled deterioration methods were further used to evaluate the field weathering resistance of 139 F2 progenies derived from the cross CM60/GC10981. There was a significant correlation between the incubator weathering and the controlled deterioration by considering the germination and viability of seeds (germination r=0.331**, viability r=0.425**, n=139). Both the modified incubator weathering and controlled deterioration were efficient for evaluating the field weathering resistance of soybean varieties. Particularly, controlled deterioration method was found to be a useful way for evaluating the field weathering resistance of
soybean seeds.