CIMMYT Report on maize improvement 1980-81

Abstract

This report, intended primarily for our scientific cooperators and for maize workers around the world, presents data from CIMMYT maize research, training, and international testing during the years 1980-81. CIMMYT's research emphasis in maize improvement continues to be on the development and improvement of normal and high-quality protein broad-based gene pools and populations. We have, accordingly, designed and implemented a continuous improvement system, whereby a wide range of materials is aggregated in gene pools for lowland, intermediate, high altitude and temperate environments. These materials are then improved to the point of being genetically ready to contribute superior new germplasm to more advanced populations. This approach, implemented in close association with national programs, has generated materials that meet specific, developingcountry requirements with superior open-pollinated varieties, white or yellow, flint or dent, early, intermediate or late in maturity, with high and dependable yields equal or superior to the best commercially available materials. Although CIMMYT emphasizes the use of varieties, they are not emphasized to the exclusion of hybrids. CIMMYT populations have proven beneficial to national hybrid breeding efforts also, where the requisite infrastructure exists to sustain such programs. Multilocational testing plays a major role in CIMMYT's maize improvement system. In Mexico, CIMMYT has a network of experiment stations located in several distinct maize-growing environments that are representative of several of the major maize environments found in other parts of the developing world. These differing environments permit CIMMYT to carry out preliminary stages of germplasm improvement for a wide range of production circumstances. In addition to Mexico's environmental diversity, its climate permits CIMMYT scientists to conduct two crop improvement cycles per year at its lowland and intermediate altitude stations. CIMMYT's maize populations enter the international testing program once the judgment is made that they have reached a level of development sufficiently high to offer superior germplasm for some part of the developing world. The following pages report on germplasrn development, including that of high-lysine maize, on various research projects, including regional ones and those concerning wide crosses, and on the various training activities related to maize.