Comportamiento de híbridos intra e inter poblaciones entre líneas endocrinadas e implicaciones de estados resultados en el desarrollo de híbridos de maíz

During the development of hybrids, non-related progenitors of opposite heterotic pattern were used. When heterotic patterns of different germplasm are not well defined, or the heterotic response among existing materials is low, it is possible to develop inter-line hybrids with some materials. The objective of this study was to determine the yield of intra and inter-population hybrids developed from lines from Pool-19 and Pool-20 (Dialelo 1); lines from Pob.32, 25 and Pool-23 (Dialelo 2); lines from Pool-24 and Pob.24 (Dialelo 3); and lines from Pob.21, Pool-23 y Pob.32 (Dialelo 4), evaluated in México, Central America and Africa. Intra and interpopulation hybrids were also evaluated in experiments involving crosses of white tropicallines to testers from Populations 21, 32, 25 and Pool-24. Interpopulation hybrids outyielded intrapopulation hybrids from 8.0 to 15.6%. In the line x tester experiments, the interpopulation hybrids also outyielded intrapopulation hybrids. In the four dialells, the best intrapopulation hybrids yielded from 92.2 to 118.6% in relation to the best control. This indicates the possibility to obtain high yielding intrapopulation hybrids. Similar results were obtained from the line x tester experiments.

Heterosis y aptitud combinatoria, para rendimiento y calidad forrajera, en poblaciones de maíz.

Twenty-eight crosses among eight populations of maize forage were evaluated in two environments (Celaya, Gto. y Gómez Palacios, Dgo. México) according with yield and quality forage. This study was carry out to determine the heterotic patterns of the populations and to identify the better populations. Sintético Forrajero and Tuxpeño Bajío populations were the best heterotic pattern, which showed the greater diversity for all traits studied. The highest forage yield was showed for cross between this two populations, 30.85 t/ha and 14.6% of heterosis. In addition, the highest general combining ability effect by forage yield over environments was of the Tuxpeño Bajío population. This suggests that Sintético Forrajero and Tuxpeño Bajío populations are the best option to begin a program of recurrent reciprocal selection. The yield of dry matter and protein was not correlated (0.06); besides, protein had very little variation between maiz forage populations.

Comportamiento de híbridos de maíz y aptitud combinatoria de líneas con caracteres contrastantes.

Twelve long-eared and twelve thick-eared lines were identified for this purpose. Single crosses were evaluated using a 12 x 12 simple lattice design with four replications in five environments during 1995. General combining ability (GCA) and Specific combining ability (SCA) estimates for grain yield were ca1culated using line x tester analysis. Line 4 (Pop.21xPop.43) registered the highest GCA value (0,58 t/ha) among long-eared lines; while in the group of thick-eared lines the highest GCA values (0,48 t/ha) corresponded to line 19 (Pop.25). The highest yield (8,35 t/ha) and SCA effect of (0,61 t/ha) was produced by cross 4 x 22 (Pop.21xPop.43) x (Pop.32). Results showed that it is important to consider the use of lines with different traits and their heterotic pattern to develop hybrids maximizing Fl performance.

Genome-based establishment of a high-yielding heterotic pattern for hybrid wheat breeding

Hybrid breeding promises to boost yield and stability. The single most important element in implementing hybrid breeding is the recognition of a high-yielding heterotic pattern. We have developed a three-step strategy for identifying heterotic patterns for hybrid breeding comprising the following elements. First, the full hybrid performance matrix is compiled using genomic prediction. Second, a high-yielding heterotic pattern is searched based on a developed simulated annealing algorithm. Third, the long-term success of the identified heterotic pattern is assessed by estimating the usefulness, selection limit, and representativeness of the heterotic pattern with respect to a defined base population. This three-step approach was successfully implemented and evaluated using a phenotypic and genomic wheat dataset comprising 1,604 hybrids and their 135 parents. Integration of metabolomic-based prediction was not as powerful as genomic prediction. We show that hybrid wheat breeding based on the identified heterotic pattern can boost grain yield through the exploitation of heterosis and enhance recurrent selection gain. Our strategy represents a key step forward in hybrid breeding and is relevant for self-pollinating crops, which are currently shifting from pure-line to high-yielding and resilient hybrid varieties.