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26 David Hoisingtonlines derived via conventional phenotypic selection. the MAS lines were found to contain similarlevels of insect resistance and performed as well. if not slightly better. in yield trials. Thus. in a verypragmatic fashion. we determined the value of MAS for a compl x trait such as insect resistance.These traits have required many years of intensive. laborious and costly breeding to advance to thecunent levels of resistance and MAS may well increase the speed and effectiveness of transfers to awider germplasm pool.A similar protocol was initiated following the development of molecular maps for an importantcomponent of drought tolerance. the anthesis-silking interval (ASl, Ribaut et al. 1996. 1997a). In thisstudy, we were able to take advantage of PeR-based markers which allowed the selection at eachgeneration to take place at a larger scale (Ribaut et al. 1997b). Instead of selecting among 400-500individuals at each generation as was done for insect resistance. we were able to select among morethan 2000. The lines selected are now being evaluated for their level of tolerance to drought and inyield trials.Our success with both of these traits, as well as the success of transferring single-gene traits (e.g.transgenes) has lead us to put more emphasis on the use of molecular marker technology inCIMMYT's improvement programs. During the course of 1998, we will be incorporating roboticsand automation into the molecular genetics efforts in order to substantially increased our capacity touse markers.ApomixisOne of the most important, although still not understood. phenomenon in breeding is heterosis ­the increased performance of a hybrid in comparison to each of its two inbred parents. Not only areyield levels significantly increased, but hybrids are also often able to resist stresses much better.Unfortunately, while hybrids have been an important component of the maize seed industry, farmersin most developing countries are not able to take advantage of hybrid seed due to the higher costs forseed production and the requirement to purchase new 'e d each season.Apomixis in plants is the asexual reproduction through seed. In other words. the seeds that areproduced on a plant are exact copies of the mother plant. Thus, if apomictic hybrids could beproduced. farmers could save seed from generation to generation to reap the benefits of heterosis. Inadditi n. national programs could produce the hybrid seed more efficiency and effectively.Unfortunately. apomixis does not exist in most of the major cereal crops, including maize. wheatand rice. It does. howe fer, exist in sev ral wild relatives of these. In particular, Tripsacwll, a wildrelative of maize. contains many ap >mictic species (Leblanc et a!. 1995b). The goal of theORSTOM-CfMMYT Apomixis Project is to transfer the apomictic character from TripsacwII tomaize, and to deliver to CfMMYT's client apomictic seed. The project has been attempting toachieve this -goal via two approaches.One of these is to transfer apomixis via wide-hybridization, using crosses between maize andapomictic TripsaclIl/l, followed by several generations of backcrossing to maize. With eachsuccessive backcross, the plants become more "maize-like", while maintaining the apomicticcharacter. The scientists have succeeded in developing BC4 materials and are now attempting toproduce the next generation which requires the transfer of the piece of the Tripsacum chromosome toa m~:ize chromosome. This effort is difficult and requires the screening of large numbers of progeny,but is aided by cytological tools available in maize and molecular and cytological methods developedby the project (Leblanc et a!. 1995a).The scientis f> are also attempting to identify and isolate the gene or genes involved in apomixis.Transposon tagging of the various stages of apomixis in Tripsacwll is underway which should lead toa better understanding of the number of genes involved and provide starting materials for theisolation of these from Tripsacum. Candidate genes. genes which are believed to be involved inapomixis, are being isolated from maize and other organisms and studied to determine if they areindeed involved in apomixis in TripsaculIl. Once the gene or genes h ve been isolated, genetic