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The International Maize and Wheat Improvement Center (CIMMYT) aims to genetically enhance both crops and generate public sector-provided products for the resource poor, e.g., drought tolerant wheat and insect resistant maize, and through international–national partnerships facilitate the acquisition of improved germplasm for non-mandate crops in the cropping systems where maize and wheat thrives; e.g., GM-papaya through a national food security undertaking in Bangladesh. The Center also engages in public awareness campaigns in projects such as Insect Resistance Maize for Africa (IRMA), which includes food, feed and environmental safety, monitoring of resistance and establishment of refugia, non-target effects and gene flow. Monitoring of genetic resources is a wide concern among the centers of the Consultative Group on International Agricultural Research (CGIAR), with an emphasis on the quality of gene banks. Decisions, policies and procedures about monitoring should be science-based, and this requires education, an area where CIMMYT and other CGIAR centers can play an important role. There will be a need to continue to evaluate the need for, and type of monitoring, as new (and unique) products are developed and released in the emergent economies of the world. [ABSTRACT FROM AUTHOR]

Comparative genetic analysis has shown that different plant species often share orthologous genes for very similar functions, especially for cereal crops. In this study, we focused on analyzing the utility of EST-SSR markers among monocots in silico and by experiment. Based on 423,611 wheat ESTs, 101,299 were found to express commonly in rice, maize and barley ESTs, which accounted for 23.94% of wheat EST data. 1707 SSR-containing ESTs (SSR-ESTs) were mined from the 101,299 homologous ESTs, which accounted for 8.8% of all the 19,434 wheat EST-SSRs. It showed that the number of homologous SSR-ESTs much less than the homologous ESTs among grasses. The number of conserved ESTs and SSR-ESTs were inversely proportional to the evolutionary distance among species. Although these SSR-ESTs were in high similarity, the number of conserved SSRs between wheat and the other three crops decreased with the increased aligning regions, and only 13 types of SSR motifs in 21 ESTs were obtained by aligning sequences over a stretch of more than 40 bp. The variation at a microsatellite came from not only the differences in the numbers of repeat units and its location shift, but also base mutations flanking microsatellite repeats. From the 428 uni-SSR-ESTs universally in the four cereals, 243 primers were designed and tested in two genotypes of each species. 154 (63.4%) primers produced clear amplicons across the four species, which showed a high efficient transferability of wheat EST-SSR markers to the other three cereal crops. [ABSTRACT FROM AUTHOR]

Doubled haploid (DH) lines are important in wheat (Triticum aestivum L.) breeding, and haploids produced via maize pollination precede DH line development. Although maize pollination has proven reliable and broadly applicable to wheat, its success is determined by the wheat and maize genotypes employed. A wheat genotype consisting of nuclear and cytoplasm components predisposing it to parthenogenesis was compared with three other genotypes, each possessing only one or neither component necessary for parthenogenesis. In a glasshouse experiment, each genotype was pollinated with maize and subsequently treated with a 2,4-Dichlorophenoxyacetic Acid (2,4-D) solution to determine if parthenogenesis affected embryo formation frequency (EFF) and haploid formation efficiency (HFE). Wheat genotypes were also treated with the 2,4-D solution alone to determine if embryos and haploid plants could be produced in vivo without maize pollination. `Salmon(K)', a parthenogenetic genotype consisting of a Salmon 1BL.1RS nucleus in a Ae. kotschyii cytoplasm, had a mean EFF of 32%; whereas, the non-parthenogenetic genotypes had mean EFF calculations ranging from 7 to 21%. Mean HFE for Salmon(K) was not significantly different than the mean HFE for non-parthenogenetic Salmon; however, EFF and HFE calculations for Salmon(K) and Salmon, each with a 1BL.1RS translocation, were generally higher than calculations for genotypes without the translocation. Salmon(K) was the only genotype to produce a 3% or higher EFF and HFE after treatment with 2,4-D alone. Parthenogenesis significantly affected the frequency at which embryos were produced after pollination with maize and the frequency at which embryos and haploid plants were produced after treatment with 2,4-D alone. [ABSTRACT FROM AUTHOR]

Participatory plant breeding (PPB) has been suggested as an effective alternative to formal plant breeding (FPB) as a breeding strategy for achieving productivity gains under low input conditions. With genetic progress through PPB and FPB being determined by the same genetic variables, the likelihood of success of PPB approaches applied in low input target conditions was analyzed using two case studies from FPB that have resulted in significant productivity gains under low input conditions: (1) breeding tropical maize for low input conditions by CIMMYT, and (2) breeding of spring wheat for the highly variable low input rainfed farming systems in Australia. In both cases, genetic improvement was an outcome of long-term investment in a sustained research effort aimed at understanding the detail of the important environmental constraints to productivity and the plant requirements for improved adaptation to the identified constraints, followed up by the design and continued evaluation of efficient breeding strategies. The breeding strategies used differed between the two case studies but were consistent in their attention to the key determinants of response to selection: (1) ensuring adequate sources of genetic variation and high selection pressures for the important traits at all stages of the breeding program, (2) use of experimental procedures to achieve high levels of heritability in the breeding trials, and (3) testing strategies that achieved a high genetic correlation between performance of germplasm in the breeding trials and under on-farm conditions. The implications of the outcomes from these FPB case studies for realizing the positive motivations for adopting PPB strategies are discussed with particular reference for low input target environment conditions. [ABSTRACT FROM AUTHOR]

Genotypic influence of both male and female parents on haploid production through interspecific crosses was studied using eight wheat and four maize genotypes. The average numbers of embryos and green haploid plantlets obtained per pollinated floret were 17.6% and 10.1%, respectively. Clear genotypic influence of the wheat genotype was detected, but heterozygosity of the wheat did not affect haploid production. Analogous response to anther culture and interspecific crossing was observed, still a wheat variety which did not respond to anther culture, produced 1.1 plantlets per pollinated spike upon maize pollination. This appears to be a major advantage of interspecific crossing compared to anther culture technique in wheat. Circumstantial evidence is presented for specific wheat × maize interaction on haploid plantlet formation. Rye chromatin enhanced haploid production but only in a complete 1B/1R substitution line. Ovaries with an embryo were found to be dispersed evenly all over the wheat spike, suggesting that within certain limits the developmental stage of ovaries and thus time of pollination within a spike are not as important as it was previously assumed. [ABSTRACT FROM AUTHOR]