International Maize and Wheat Improvement Center

About: International Maize and Wheat Improvement Center is a nonprofit organization based out in Texcoco, Mexico. It is known for research contribution in the topics: Population & Agriculture. The organization has 1976 authors who have published 4799 publications receiving 218390 citations.

Soil water content, maize yield and its stability as affected by tillage and crop residue management in rainfed semi-arid highlands

Abstract: Rainfed crop management systems need to be optimized to provide more resilient options to cope with projected climatic scenarios forecasting a decrease in mean precipitation and more frequent extreme drought periods in Mexico. Soil water content (0–60 cm) was measured during three crop cycles in maize plots with different agronomic management practices in a long-term rainfed experiment (established in 1991) in the highlands of Mexico. Maize yields of 1997–2009 were reported. Crop management practices varied in (1) tillage (conventional [CT] vs. zero tillage [ZT]) and (2) residue management (full or partial retention and removal). ZT with residue retention had higher soil water content than management practices involving CT and ZT with residue removal which provided a buffer for drought periods during the growing seasons. In 2009, a cycle with a prolonged drought during vegetative growth, this resulted in yield differences of up to 4.7 Mg ha−1 between ZT with (partial) residue retention and the other practices. Averaged over 1997–2009, these practices had a yield advantage of approximately 1.5 Mg ha−1 over practices involving CT and ZT with residue removal. ZT with (partial) residue retention used rainfall more efficiently and resulted in a more resilient agronomic system than practices involving either CT or ZT with residue removal.

Wheat breeding assisted by markers: CIMMYT's experience

Abstract: Significant progress has been made in the characterization of loci controlling traits of importance using molecular markers. A number of markers are currently available in wheat for genes of interest to the breeders. Markers can be used to better characterize parental material, thereby improving the efficiency and effectiveness of parental selection for crossing and to track genes in segregating progenies through the selection process. Although a number of breeding programs are using molecular markers at modest levels, the costs associated with marker assisted selection (MAS) are frequently cited as the main constraint to their wide-spread use by plant breeders. However, this is likely to change when user-friendly, high-throughput, automated marker technologies based on single nucleotide polymorphisms become available. These evolving technologies will increase the number of available markers, and will improve the efficiency, throughput, and cost effectiveness of MAS, thereby making it more attractive and affordable to many breeding programs. This article examines the extent to which molecular markers have been used at the International Maize and Wheat Improvement Center (CIMMYT) in applied wheat breeding and reviews the limited publicly available information on MAS from other wheat breeding programs. As markers are currently available for relatively few traits, we believe that MAS must be integrated with ongoing conventional breeding to maximize its impact. When used in tandem with phenotypic selection, MAS will improve response to selection for certain traits, thereby increasing rates of genetic progress.