Search

New technologies have been developed over the last few years aiming to support breeding pipeline optimization for long‐term genetic gains. However, the implementation of these new tools and their impact on any breeding program's budget are not well studied. Here, we compare multiple breeding pipeline strategies accounting for genomic selection and high‐throughput phenotyping (HTP) by means of hybrid gain and cost‐effectiveness. We simulated a hybrid crop breeding program through coalescent theory. We compared two strategies for parental updates and four breeding pipelines: conventional breeding pipeline; conventional breeding pipeline with HTP; conventional breeding pipeline with genomic selection; conventional breeding pipeline with genomic selection and HTP. All analyses were implemented under three different levels of genotype‐by‐environment interaction (G×E) and two trait heritabilities (0.3 and 0.7). Overall, the results show that scenarios with early parental selection perform better than the others. In addition, the implementation of HTP delivered the highest hybrid gain in the long‐term, whereas the implementation of genomic selection seems to be more cost‐effective. We suggest, considering breeding programs with complex trait inheritance and accounting for higher levels of G×E, investing in breeding pipelines accounting for genomic selection as a strategy to create and maintain long‐term hybrid gain. Moreover, considering an unconstrained budget, the investment in both, genomic selection and HTP, represents the best strategy. Hence, these results provide strategies that may aid breeders in optimizing self‐pollination breeding programs. Core Ideas: Early parental selection has the potential to increase long‐term genetic performance.High‐throughput phenotyping (HTP) can aid breeding program improvement.Breeding pipelines focusing on complex traits should consider the implementation of genomic selection and HTP. [ABSTRACT FROM AUTHOR]

The genetic diversity of a comprehensive germplasm collection involving 192 Jatropha curcas L. accessions collected throughout Brazil, spanning a wide latitudinal range from the states of Maranhao (1[degrees]49' S, 44[degrees]52' W) to Rio Grande do Sul (29[degrees]33' S, 55[degrees]07' W), was studied with 96 random amplified polymorphic DNA (RAPD) primers and six selected microsatellite markers. Only 23 of the 381 replicated RAPD markers and one microsatellite were polymorphic. Surprisingly, all accessions were homozygous at all but one microsatellite, in contrast with the outcrossing mating system reported for the species, suggesting that J. curcas not only supports selfing but possibly breeds by geitonogamy. Similarity based clustering revealed only 43 unique multilocus profiles in the 192 accessions. The probabilities of accessions with indistinguishable multilocus profiles being true duplicates varied between 83 and 99%. No relationship between clustering of accessions and geographic origin was observed, suggesting that J. curcas has experienced a widespread dispersion across regions by seeds and possibly vegetative propagules. The narrow genetic base and extent of potentially duplicated accessions likely reflects a recent common ancestry, drift, and intensive selection of the currently cultivated materials since the time of introduction. This result highlights an urgent need for the introduction of new and diverse accessions to this germplasm collection if Brazil is to drive and sustain successful breeding programs. doi: 10.2135/cropsci2010.02.0112