Development and fecundity of the foxglove aphid, Aulacorthum solani (Hemiptera: Aphididae) were investigated at ten constant temperatures (photoperiod: 15L:9D) from 2.5 to 30℃ on soybean (Glycine max) leaves. The nymphs couldn’t emerge to adults at 2.5 and 30℃. The lower development temperature threshold and thermal constant of development completion estimated with a linear development model in nymph were 5.02℃ and 131.2 degree-days. The lethal temperatures were estimated as 33.9 and 32.5℃ with Lactin 2 and Logan 6 non-linear models, respectively. Mean generation time (from 78.4 to 11.8 d) decreased with increasing temperatures (from 7.5 to 27.5℃). The highest net reproductive rate (77.4) was observed at 20℃. The highest intrinsic rates of population increase (0.282) and shortest population doubling times (2.07 d) were recorded at 25℃.

Adult longevity and fecundity of the foxglove aphid, Aulacorthum solani Kaltenbach, were studied at 12.5~25℃ with 60~70% RH under 16L:8D and the results were put together to build a life table. The longevity of foxglove gradually increased with decreasing temperature below 25℃. Also total fecundity increased with decreasing temperature and highest fecundity was 74.1 nymphs per female at 15℃. However, daily fecundity increased with increasing temperatures up to 20℃ showing 2.9 nymphs per day and thereafter decreased. Net reproduction rate (R₀) was highest of 58.7 at 15℃. The intrinsic rate of increase per day (r<SUB>m</SUB>) and the finite rate of increase per day (λ) were highest of 0.27 and 1.32, respectively and the doubling time (Dt) was shortest of 2.52. the mean generation time (T) was 10.99 at 22.5℃.

The development of Aulacorthum solani (Kaltenbach) was studied at temperatures ranging from 12.5 to 27.5℃ under 65±5% RH, and a photoperiod of 16:8 (L:D). Mortality of 1st~2nd nymph was higher than that of 3rd~4th nymph at the most temperature ranges whereas at high temperature of 27.5℃, more 3~4th nymph stage individuals died. The total developmental time ranged from 16.9 days at 12.5℃ to 6.6days at 22.5℃, suggesting that higher the temperature, faster the development. However, at higher temperature of 25℃ the development took 7.4 days. The lower developmental threshold temperature and effective accumulative temperatures for the total immature stage were 0.08℃ and 162.8 day-degreeslated development. The nonlinear shape of temperature rewas well described by the modified Sharpe and DeMichele model. When the normalized cumulative frequency distributions of developmental times for each life stage were fitted to the three-parameter Weibull function, attendance of shortened developmental times was apparent with in 1~2nd nymph, 3~4th nymph, and total nymph stages in descending order. The coefficient of determination r² ranged between 0.86 and 0.91.

Foxglove aphid, Aulacorthum solani (Kaltenbach), is a Hemipteran insect that infected a wide variety of plants worldwide and caused serious yield losses in crops. The objective of this study was to identify the putative QTL for foxglove aphid resistance in wild soybean, PI 366121, (Glycine soja Sieb. and Zucc.). One hundred and forty one F2-derived F8 recombinant inbred lines developed from a cross of susceptible Williams 82 and resistant PI 366121, were used. The phenotyping of antibiosis and antixenosis was done through choice and no-choice assays with total plant damage (TPD) and primary infestation leaf damage (PLD); a genome-wide molecular linkage map was constructed with 504 single nucleotide polymorphism markers utilizing a GoldenGate assay. Using inclusive composite interval mapping analysis for foxglove aphid resistance, one major candidate QTL on chromosome 7 and 3 minor QTL regions on chromosome 3, 6 and 18 were identified. The major QTL on chromosome 7 showed both antixenosis and antibiosis resistance responses. However, the minor QTLs showed only antixenosis resistance response. The major QTL mapped to a different chromosome than the previously identified foxglove aphid resistance QTL, Raso1, from the cultivar Adams. Also, the responses to the Korea biotype foxglove aphid were different for Raso1, and the gene from PI 366121 against the Korea biotype foxglove aphid were different. Thus the foxglove aphid resistance gene from PI 366121 was determined to be an independent gene to Raso1 and designated to Raso2. This result could be useful in breeding for new foxglove aphid resistant soybean cultivars.

Foxglove aphid, Aulacorthum solani (Kaltenbach), is a Hemipteran insect that infected a wide variety of plants worldwide and caused serious yield losses in crops. The foxglove aphid resistance gene, Raso2 was previously mapped from PI 366121 (Glycine soja Sieb. and Zucc.) to a 26cM marker interval on soybean chromosome 7. The development of additional genetic markers, which are mapped closer to Raso2 were required to accurately position the gene to improve the effectiveness of marker assisted selection. The objective of this study was to narrow down the putative QTL region, which is responsible to foxglove aphid resistance in PI366121 using recently developed high-density 180K Axiom SoyaSNP genotyping array. One hundred and forty one F8-derived F12 recombinant inbred lines developed from a cross of susceptible Williams 82 and resistant PI 366121, were used to generate a fine map of Raso2 interval. The phenotyping of antibiosis and antixenosis was done through choice and no-choice assays with total plant damage (TPD) and primary infestation leaf damage (PLD). The composite interval mapping analysis showed that the physical interval between two flanking makers, which was corresponding to Raso2, was narrowed down to 500kb on the Williams 82 genome assembly (Glyma2.0), instead of 4Mb in the previous report using Goldengate assay. In the Raso2 interval, there are about 60 candidate genes, including 4 of NBS-containing putative R genes. This result could be useful in breeding for new foxglove aphid resistant soybean cultivars.