BREEDING POTENTIAL OF MAIZE ACCESSIONS FROM ARGENTINA, CHILE, USA, AND URUGUAY

The Latin American Maize Project (LAMP) evaluated nearly 12 000 maize (Zea mays L,) accessions in 12 countries to select germ-plasm that can he used in breeding programs to improve commercial materials, In Arge ntina, Chile, Uruguay, and the USA, 1692 and 988 native accessions wer e evaluated in the first and second period respectively. Sixty nine se lected accessions were evaluated in all countries in the third stage. Accessions per se showed silk delay, indicating a lack of adaptation. The 69 selected accessions topcrossed with B73 x B14A, Oh43 x Mo17, an d SR76 were evaluated in the four countries to (i) identify temperate accessions from Latin America and the USA that could enhance yield, ta ssel and silk synchronization, lodging resistance, and maturity; and ( ii) identify the U,S, heterotic group to which the accessions belong. The topcross results identified germplasm equal or superior to the per formance of the checks in all countries, indicating that selected germ plasm could be used to increase yield. Even though topcrosses showed s ignificant improvement for silk delay and stalk lodging across the acc essions, additional improvement is needed to facilitate wider use of t he material, The Argentinean accessions had the best mean per se and t opcross performance. Some accessions performed well in most countries and should be included in cooperative enhancement efforts.