Field evaluation of soybean for Mexican bean beetle resistance. II. Maturity groups III, IV, and V.

Reference Report for IND90024474

Title:	Field evaluation of soybean for Mexican bean beetle resistance. II. Maturity groups III, IV, and V.
Authors:	Kraemer, M.E., Rangappa, M., Mebrahtu, T., Benepal, P.S.
Source:	Crop Sci. 1990, 30(2):374-377
Abstract:	Field screening of soybean, Glycine max (L.) Merr., germplasm for resistance to insect defoliation was undertaken because of the narrow genetic base currently available to plant breeders and the lack of a comprehensive screening for resistance in most maturity groups (MGs). This study was conducted to evaluate plant introductions (PIs) in MGs III, IV, and V for resistance to defoliation by Mexican bean beetle (MBB), Epilachna varivestis Mulsant. All available PIs were screened to 475822C, 476914, and 424553 in MGs III, IV, and V, respectively, at the Randolph Research Farm of Virginia State University, Petersburg, VA. Resistance was determined by visually estimating the percent defoliation by MBB. Soybean accessions were initially screened in 2-m rows. Selections from these screenings were twice retested in triplicate. Maturity Group V contained most of the resistant germplasm, including PIs 423901-1, 417235 ('Ouu 3'), and 200450 ('Akita Ahi'). However, two breeding lines (L76-0132 and L76-0049), derived from the highly resistant PI 171451 in MG VII, had the least defoliation in MG V. Three moderately resistant PIs (360847 ['Shiromeyntaka'], 248511 ['Hakuho No. 1'], and 407820) were found in MG IV. PI 417152 ('Mikuri 42') (MG III) also showed some resistance. Higher levels of insect resistance appear to be present in later maturity group soybean germplasm.

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