Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2003
Publication Date: 8/17/2003
Citation: XU, W., BLANCO, M.H. 2003. MINING GENES FROM TROPICAL MAIZE GERMPLASM TO IMPROVE DROUGHT TOLERANCE AND CORN EARWORM RESISTANCE [abstract]. p. 74-75.
Technical Abstract: The Germplasm Enhancement of Maize Project (GEM) is a cooperative effort involving the USDA-ARS, land grant universities, Non-governmental organizations (NGO), and the private sector of the seed and processing industries. The objective of the project is to broaden the germplasm base of maize through cooperative research efforts to identify and characterize exotic germplasm sources, and develop useful methods for incorporating and evaluating traits (alleles) into the germplasm base through plant breeding. Drought stress causes significant yield losses throughout the world, and is a very common problem throughout the tropics. Exotic germplasm therefore represents a potential useful source of alleles for drought tolerance. Seventy-one GEM breeding crosses involving tropical and temperate germplasm were grown in a randomized complete block design and evaluated under three soil moisture regimes in Lubbock, TX in 2002 and 2003. All entries were evaluated (including three adapted commercial checks) for stay green, days to pollen shed, ears per plant, corn ear worm (CEW) damage (Helicoverpa zea), mold resistance, and yield under each treatment of moisture stress. Drought stress increased the number of barren plants, reduced yield, and enhanced premature plant senescence on an overall basis. Severe CEW damage was highly correlated with the level of molded kernels (r=0.68**). Nine GEM breeding crosses were identified having lower CEW damage than average, while eleven had greater ear length than the checks. Some GEM breeding crosses were similar to the adapted checks in yield, but had significantly better stay green. Fifteen GEM breeding crosses exhibited a favorable combination of desirable traits including good yield potential, CEW and mold resistance, stay green, long ears, and early maturity. The fifteen top breeding crosses included three temperate accessions and twelve from tropical regions as follows: Antigua (3), Argentina (1), Brazil (3), Chile (1), Cuba (2), Guadeloupe (1) Puerto Rico (2), Uruguay (1), and Venezuela (1). These GEM breeding crosses are potentially useful sources of germplasm for maize breeding programs for improving drought, CEW, and mold tolerance.