Breeding without Breeding: Is a Complete Pedigree Necessary for Efficient Breeding?

Complete pedigree information is a prerequisite for modern breeding and the ranking of parents and offspring for selection and deployment decisions. DNA fingerprinting and pedigree reconstruction can substitute for artificial matings, by allowing parentage delineation of naturally produced offspring. Here, we report on the efficacy of a breeding concept called “Breeding without Breeding” (BwB) that circumvents artificial matings, focusing instead on a subset of randomly sampled, maternally known but paternally unknown offspring to delineate their paternal parentage. We then generate the information needed to rank those offspring and their paternal parents, using a combination of complete (full-sib: FS) and incomplete (half-sib: HS) analyses of the constructed pedigrees. Using a random sample of wind-pollinated offspring from 15 females (seed donors), growing in a 41-parent western larch population, BwB is evaluated and compared to two commonly used testing methods that rely on either incomplete (maternal half-sib, open-pollinated: OP) or complete (FS) pedigree designs. BwB produced results superior to those from the incomplete design and virtually identical to those from the complete pedigree methods. The combined use of complete and incomplete pedigree information permitted evaluating all parents, both maternal and paternal, as well as all offspring, a result that could not have been accomplished with either the OP or FS methods alone. We also discuss the optimum experimental setting, in terms of the proportion of fingerprinted offspring, the size of the assembled maternal and paternal half-sib families, the role of external gene flow, and selfing, as well as the number of parents that could be realistically tested with BwB

Effets de la double symbiose Rhizobium-Glomus spp. sur la croissance de Leucaena leucocephala (Lam.) de Wit en pépinière, et dix mois après transplantation au Zaïre

Effects of dual inoculation with Rhizobium and Glomus spp. on the growth of Leucaena leucocephala (Lam.) de Wit in the nursery, and ten months after outplanting in Zaire. This work underlines the utility to inoculate in the nursery Leucaena leucocephala (Lam.) de Wit, with efficient strains of Rhizobium and endomycorrhizal fungi, in order to ensure good initial plant growth after outplanting. In general, soil fumigation in the nursery allowed growth enhancement of control plants and the best effect of biofertilizers was obtained in the nursery and ten months after outplanting. Glomus vesiculiferum (Thaxter) Gerdemann and Trappe associated or not with Rhizobium TAL 1145 likely produced the same effect by using natural soil in the nursery

Effects of buffer system pH and tissue storage on starch gel electrophoresis of allozymes in three tropical tree species

The effects of 16 different electrophoresis buffer pHs, 4 tissue storage conditions and 5 storage times on starch gel electrophoresis of 18 enzymes were determined to design a genetic variation sampling strategy for an isozyme study of 3 tropical tree species, Racosperma auriculiforme, R mangium, and Terminalia superba. The pH of the buffer systems had a significant effect on the number of putative gene loci and alleles resolved, and the staining intensity of the 18 enzymes assayed. For Racosperma species, 2 buffer systems B7 (Tris-citrate gel, pH 9.0: lithium hydroxide-borate electrode, pH 8.5) and H 7 (histidine-EDTA gel, pH 7.6: Tris-citrate electrode, pH 7.7) gave the highest average performance in resolving power. All buffer systems yielded poor results for Terminalia. Freezing of Racosperma embryos for up to 2 months did not seriously affect enzyme activity. However, freezing cotyledon tissue of Terminalia decreased enzyme activity over a 2-month period. In general, frozen tissues either with or without extraction buffer, were consistently better than frozen tissues with extraction buffer and DMSO. Three classes of enzymes were defined, based on their stability under the standardized storage conditions in vivo. Using the best buffer systems (B7 and H7) and tissue storage conditions (To or T1), 42, 43, and 32 zones of activity were resolved for R auriculiforme, R mangium, and T superba, respectively. Genetic inference of enzyme variants was made for 31 and 32 putative gene loci in R auriculiforme and R mangium, respectively. Mean number of putative alleles per locus was 3.0 for R auriculiforme and 2.4 for R mangium.Effets du pH du système de tampons et de la conservation des tissus en électrophorèse sur gel d'amidon d'allozymes chez 3 espèces d'arbres tropicaux. En vue de planifier une stratégie d'échantillonnage de la variabilité génétique de 3 espèces d'arbres tropicaux, Racosperma auriculiforme, R mangium et Terminalia superba, les effets de 16 différents pH de tampons d'électrophorèse (tableau /), de 4 conditions de conservation des tissus et de 5 durées de conservation ont été évalués pour l'électrophorèse sur gel d'amidon de 18 enzymes. La résolution du nombre de loci et d'allèles présumés possibles ainsi que l'intensité de coloration des 18 enzymes étaient influencées de manière sensible par le pH des systèmes de tampons. Pour les espèces de Racosperma, deux systèmes de tampons, B 7 (Tris-citrate, pH du gel 9.0: hydroxyde de lithium, borate- pH de l'électrode 8,5) et H7 (histidine, EDTA, pH du gel 7,6: Tris-citrate pH de l'électrode 7,7) ont donné le meilleur pouvoir moyen de résolution (fig 1-11, tableau II). Tous les systèmes de tampons ont entraîné des résultats insatisfaisants chez Terminalia. La congélation des embryons de Racosperma pour plus de 2 mois n'a pas affecté sérieusement l'activité enzymatique. En revanche, la congélation des cotylédons de Terminalia au-delà de 2 mois a diminué l'activité enzymatique. En général, les tissus congélés avec ou sans tampon d'extraction, donnaient constamment de meilleurs résultats que les tissus congélés avec le tampon d'extraction supplémenté de DMSO (fig 12). Trois classes d'enzymes ont été définies, sur la base de leur stabilité sous les conditions in vivo standardisées (tableau III). En utilisant les meilleurs systèmes de tampons (B7 et H7) et conditions de conservation (T0 ou T1), 42, 43 et 32 zones d'activité étaient séparées respectivement pour R auriculiforme, R mangium et T superba. L'inférence génétique de 31 et 32 loci présumés a été conduite pour R auriculiforme et R mangium, respectivement (fig 13-17). Le nombre moyen d'allèles présumés par locus était de 3,0 pour R auriculiforme et de 2,4 pour R mangium (tableau IV)

Genetic Diversity and Population Structure of Acacia senegal (L) Willd. in Kenya

The level of genetic diversity and population structure of Acacia senegal variety kerensis in Kenya was examined using seven polymorphic nuclear microsatellite loci and two chloroplast microsatellite loci. In both chloroplast and nuclear datasets, high levels of genetic diversity were found within all populations and genetic differentiation among populations was low, indicating extensive gene flow. Analysis of population structure provided support for the presence of two groups of populations, although all individuals had mixed ancestry. Groups reflected the influence of geography on gene flow, with one representing Rift Valley populations whilst the other represented populations from Eastern Kenya. The similarities between estimates derived from nuclear and chloroplast data suggest highly effective gene dispersal by both pollen and seed in this species, although population structure appears to have been influenced by distributional changes in the past. The few contrasts between the spatial patterns for nuclear and chloroplast data provided additional support for the idea that, having fragmented in the past, groups are now thoroughly mixed as a result of extensive gene flow. For the purposes of conservation and in situ management of genetic resources, sampling could target a few, large populations ideally distributed among the spatial groups identified. This should ensure the majority of extant variation is preserved, and facilitate the investigation of variation in important phenotypic traits and development of breeding populations

Ectomycorrhizal Colonization and Diversity in Relation to Tree Biomass and Nutrition in a Plantation of Transgenic Poplars with Modified Lignin Biosynthesis

Wood from biomass plantations with fast growing tree species such as poplars can be used as an alternative feedstock for production of biofuels. To facilitate utilization of lignocellulose for saccharification, transgenic poplars with modified or reduced lignin contents may be useful. However, the potential impact of poplars modified in the lignification pathway on ectomycorrhizal (EM) fungi, which play important roles for plant nutrition, is not known. The goal of this study was to investigate EM colonization and community composition in relation to biomass and nutrient status in wildtype (WT, Populus tremula6Populus alba) and transgenic poplar lines with suppressed activities of cinnamyl alcohol dehydrogenase, caffeate/ 5-hydroxyferulate O-methyltransferase, and cinnamoyl-CoA reductase in a biomass plantation. In different one-year-old poplar lines EM colonization varied from 58% to 86%, but the EM community composition of WT and transgenic poplars were indistinguishable. After two years, the colonization rate of all lines was increased to about 100%, but separation of EM communities between distinct transgenic poplar genotypes was observed. The differentiation of the EM assemblages was similar to that found between different genotypes of commercial clones of Populus6euramericana. The transgenic poplars exhibited significant growth and nutrient element differences in wood, with generally higher nutrient accumulation in stems of genotypes with lower than in those with higher biomass. A general linear mixed model simulated biomass of oneyear- old poplar stems with high accuracy (adjusted R2 = 97%) by two factors: EM colonization and inverse wood N concentration. These results imply a link between N allocation and EM colonization, which may be crucial for wood production in the establishment phase of poplar biomass plantations. Our data further support that multiple poplar genotypes regardless whether generated by transgenic approaches or conventional breeding increase the variation in EM community composition in biomass plantations.Open-Access-Publikationsfonds 2013peerReviewe