the Symposium on Wheats for More Tropical Environments - cimmyt

3~from o<strong>the</strong>r crops. During <strong>the</strong> period1979 to 1983, an average of 24,000hectares was planted to wheat inChaco, from which 16,000 hectaresyielded an average of 1,200 kglha(Table 1). Approximately 4,500hectares were under wheat cultivationin <strong>the</strong> province of Formosa during <strong>the</strong>same period, with a yield similar to thatof Chaco.The marked decline in <strong>the</strong> area underwheat cultivation in <strong>the</strong> last few yearshas been due, in great part, tounfavorable wea<strong>the</strong>r conditions, suchas drought in some years, excessivehumidity in o<strong>the</strong>rs and late frosts.Never<strong>the</strong>less, in spite of <strong>the</strong>se adverseconditions, wheat remains <strong>the</strong> onlywinter crop which fits into <strong>the</strong> existingrotation patterns with <strong>the</strong> predominantrow crops of sorghum, cotton,sunflower and soybeans. Wheat is ofeconomic benefit to <strong>the</strong> farmers, as itbrings in income at an opportune timeof <strong>the</strong> year.Wheat production in nor<strong>the</strong>astArgentina is sufficient to meet <strong>the</strong> localdemand of <strong>the</strong> flour milling industry inChaco and nor<strong>the</strong>rn Santa Fe province.It is also possible to export some wheatto neighboring Bolivia, Brazil andParaguay, countries which representimportant markets for Argentineproducts.Wheat Research inNor<strong>the</strong>ast ArgentinaWhen wheat cultivation started in <strong>the</strong>early 1960s, <strong>the</strong> commercial varietiesused came from <strong>the</strong> traditional wheatgrOWingregions in <strong>the</strong> humid pampas.As <strong>the</strong>se varieties were not ideallyadapted to <strong>the</strong> conditions of <strong>the</strong> area,limited yields were obtained withconsiderable risk to <strong>the</strong> farmer.In 1972, because of <strong>the</strong> need to increasewheat production, a research programwas initiated to develop new varietiesfor <strong>the</strong> Chaco region, in coordinationwith <strong>the</strong> National Council for WheatPrograms. The objective of <strong>the</strong> programwas to investigate <strong>the</strong> productionproblems caused by <strong>the</strong> extremeenvironmental variation in <strong>the</strong> area,such as drought, late frosts, hightemperatures, low fertility and diseaseproblems.The specific objectives of <strong>the</strong> programwere:Table 1. Wheat area and production, Chaco • Develop varieties of high yieldprovince, Argentina, 1979 to 1984potential and broad adaptation;• Develop varieties of medium-to-IateArea Area Grainmaturity with good agronomic type;planted harvested yieldSeason (ha) (ha) (kg/ha) • Develop varieties with resistance tosteA rust (Pucctnia graminis tritici),1979-80 14,200 11,000 1,201 leaf rust (Pucctnia recondita tritict),1980-81 44,500 7,900 1,021 septoria leaf blotch (Septoria tritici),1981-82 11,600 11,100 1,562 glume blotch (Septoria nodorum),1982-83 33,500 32,100 929 diseases caused by Helmtnthosportum1983-84 16,600 15,650 1,295spp., scab (Fusartum spp.)and powdery mildew (Erystphegraminis trtttci);5-yearaverage 24,100 16,000 1,200 • Develop varieties with tolerance toshriveling, andSource: Chaco Extension Service andPlanning Office