Discipline interactions in the quest to adapt plants to soil stresses through genetic improvement.

Tropical soils are inferior in fertility compared to temperate soils. The "Tropical Belt" of the world contains 58 percent of the world's land area suitable for agriculture production. The adaptation of plants for tropical agriculture is frequently synonymous with adapting plants to soil fertility stress constituents. This phenomenon is by no means limited to the tropics, as the acid soils and subsoils of the Southeast U.S. are examples where plant improvement programs are often associated with adapting plants to soil stress. Modern plant breeding has traditionally produced crop cultivars that are very productive when combined with an intensive input management regime. The merits and difficulties of establishing collaborative, multidisciplinary, interdisciplinary research and crop cultivar development programs to increase nutrient use efficiency and tolerance to toxic elements are reviewed and discussed. The goal for increasing nutrient use efficiency is not to increase the mining potential of soils by plants or develop a temporary fix for soil fertility problems, but rather to transform marginal agriculture land suitable for agriculture production into productive sustainable agriculture land by developing and utilizing cultivars with soil stress tolerance and improved nutrient use efficiency

Sorghum in Brazil.

The area planted to grain sorghum in Brazil has increased since 1970. The major production areas are the states of Rio Grande do Sul and Sao Paulo. Even though the national average yield is 2.5 tonne/ha, results of national trials indicate that this yield can be doubled. The use of sorghum grain in animal feed, at the rate of 8% of the ration, will create a demand of 1 million tonnes of sorghum grown on 400 000 ha by 1980. Recent problems in seed production have restricted the expansion of sorghum. Even though the potential for 1978/1979 is in excess of 1 million ha, the area planted probably will not exceed 200 000 ha due to seed shortages. Forage sorghum is being used in some regions, and sweet sorghum appears to be excellent for the production of alcohol used as a fuel mixture with gasoline. The principal diseases are anthracnose, rust, sorghum downy mildew, and grain "weathering". Sorghum research in Brazil is coordinated by the National Maize and Sorghum Research Center which is a part of the Brazilian Enterprise for Agricultural Research (EMBRAPA). This research is organized in 13 subprojects. In 1977, two grain hybrids, two forage hybrids, and five sweet sorghum varieties with good agronomic characteristics and disease resistance were released to the farmer. Additional hybrids and genetic material will be released in 1979

Sorgo granífero (Sorghum bicolor (L.) Moench) de alta lisina no Brasil.

Pequenas quantidades de sementes de duas linhagens de sorgo, com um gene recessivo simples para lisina, descoberto recentemente na Colecao Mundial de Sorgos da Universidade de Purdue, West Lafayette, Indiana, U.S.A., foram plantas para multiplicacao de sementes pela EMBRAPA e pela EPAMIG em Sete Lagoas, Minas Gerais. As linhagens mostraram nao adaptadas, com porte alto, maturidade tardia e susceptibilidade a doencas. Sementes geneticas de duas linhagens de alta lisina e algumas selecoes de porte baixo e precoce poderao ser requisitadas. As propriedades quimicas e biologicas do sorgo com o mutante para alta lisina foram previamente revisadas