Submitted to: Plant Disease Management Reports
Publication Type: Research notes
Publication Acceptance Date: 2/7/2007
Publication Date: 12/20/2007
Citation: Thies, J.A., Fery, R.L. 2007. Reactions of Regional Cooperative Southernpea (cowpea) Breeding Lines to Southern Root-knot Nematode Race 3, 2005. Plant Disease Management Reports (online). Report 1:V019. DOI: 10.1094/PDMR01. The American Phytopathological Society, St. Paul, MN. Interpretive Summary:
Technical Abstract: Southernpea breeding lines from the Regional Southernpea Cooperative Trial were evaluated for resistance to southern root-knot nematode, Meloidogyne incognita race 3, in a greenhouse test. The experimental design was a randomized complete block with four replicates. Each plot consisted of five seeds of an entry planted 10 cm apart and 2 cm deep in a greenhouse bench containing steam-pasteurized soil (2 parts sand : 1 part loamy sand). Nematode inoculum was cultured on Rutgers tomato (Lycopersicon esculentum) in the greenhouse. Eggs were extracted from tomato roots using 0.5% NaOCl. Seeds were planted on 3 Nov 05 and the soil surrounding each seed was infested with ca. 3,000 M. incognita eggs suspended in 5 ml H2O. The greenhouse conditions were maintained for favorable growth of southernpea (25-32 °C) and nematode development. The soil was irrigated as needed. On 15 Dec 05, the roots of the plants were lifted, washed, and evaluated for resistance to root-knot nematode using a 1 to 5 rating system, where 1 = 0 to 3% of root system galled or covered with egg masses, 2 = 4 to 25%, 3 = 26 to 50%, 4 = 51 to 79%, and 5 = >80% of root system galled or covered with egg masses. Ratings of 1 to 2.9 are considered resistant and ratings of 3.0 to 5.0 are susceptible. The standard resistant and susceptible check cultivars performed as expected. Four observational lines (AR01-1704, AR01-1764, AR01-1781, and TX 2028-2-1 BEgc ) and five advanced lines (TX 2044-5-1 PEgc, TX 2028-1-3 BEgc, TX 2036-4-1 PE, LA 95-17, and LA 96-10 ) were resistant (R), similar in reaction to the resistant check Mississippi Silver. Three observational lines (AR01-821, LA 92-11, and LA 95-18) and six advanced lines (US-1071, US-1080, AR01-1293, AR01-176, AR01-874, and LA 96-30) were susceptible (S), similar in reactions to the susceptible checks Arkansas Blackeye #1, Early Acre, Pinkeye Purple Hull, and New Era.