Although intensively studied, few works had looked into S. pennellii’s ability to cope with water-deficit conditions from a breeding point of view. In this study, we assessed potential traits of S. pennellii, that had previously been linked to high yields in other plant species, under long-term water-limited conditions and made a parallel with plant yield. For this purpose, the drought-resistant tomato genotypes IL 3–5 and IL 10–1, and the drought-sensitive IL 2–5 and IL 7–1 at seed level, together with both parents the S. pennellii accession LA 716 and the cultivar M82 were kept at 50 and 100% ASW throughout the growing season. Our findings confirm the superiority of LA 716 under water-limited conditions compared to the other S. lycopersicum genotypes in terms of plant water status maintenance. Percentual reduction on plant yield was higher in IL 3–5 and IL 10–1 than in M82 plants, indicating no correlation between drought resistance on germination and plant productive stages. A strong positive correlation was found between fruit yield and A, gs, and Ψleaf at 50% ASW, suggesting these traits as important selection criteria. LT and gmin, LA 716’s most promising traits, did not show a linear correlation with fruit yield under low water regimes. This study unravels traits behind tomato performance under water-limited conditions and should work as guidance for breeders aiming at developing drought-resistant tomato cultivars.

This work aimed to study the inheritance of resistance to Phytophthora infestans in tomato plants, using the maximum likelihood estimation function. The susceptible cultivar Santa Clara (Solanum lycopersicum) was used as the female genitor and the P. infestans resistant S. habrochaites f. glabratum accession (BgH 6902) as the male genitor. F 1 plants from the crossing were self-pollinated to produce F 2 progenies, and also backcrossed with P r and P S to produce BC 1:r and BC 1:S generations, respectively. The tomato plants were inoculated 50 days after transplanting. Disease severity was evaluated via a diagrammatic scale. Comparison of the genetic models created using the maximum likelihood function revealed that the inheritance of resistance to P. infestans in S. habrochaites is conferred by a major gene with additive and dominance effects, polygenes with additive effects, plus the environmental effect. Vertical resistance can be explored using genes with major effects. Programs of recurrent and makerassisted selection are considered efficient strategies with which to select genotypes that hold P. infestans resistance conferred by polygenes.

Hancornia speciosa Gomes is one of the native fruit species most frequent in the Brazilian Savanna. Studies on the genetic variability of quantitative traits for this species are scarce and the identification of accessions with the best agronomic traits may support strategies for conservation and breeding programs. This study aimed to estimate the genetic diversity of accessions from the H. speciosa germplasm collection of the Universidade Federal de Goiás (Goiânia, Goiás state, Brazil) and rank them based on a selection index combining eleven agronomic traits. A total of 192 individual accessions from 57 progenies, from 29 natural populations, were evaluated. The data were subjected to multivariate analysis and the individuals and progenies evaluated using the FAI-BLUP selection index. The Tocher cluster analysis allowed grouping the progenies into ten divergent clusters and the individuals into 18 divergent clusters. The simultaneous selection of traits based on the FAI-BLUP index may be recommended while maintaining the potential variability in the population resulting from the recombination. The individual selection proved to be more effective than the selection based on progenies means, because it exploits the genetic variation among and within progenies.

No abstract

This study was performed to introduce the allele Bush of commercial cultivars with a bush growth habit into Cucurbita moschata accessions and select the best crossings for production potential and standard fruit shape “Menina Brasileira” through general combining ability (GCA) and specific combining ability (SCA). To determine GCA and SCA, a partial diallel analysis was performed. The parental group (group I) consisted of two cultivars containing the dwarfism bush gene, and the second group (Group II), formed by five accessions of UFV Vegetable Germplasm Bank, with high production potential and fruit shape “Menina Brasileira”. We evaluated: productivity (PROD), fruit shape (FORM), growth rate until the 50th day after transplanting (CRESC), and length of the main stem on the 50th day (COMP). Significant differences were noticed for CRESC and COMP only between GCA of parents belonging to group I, in which Zapallo stood out. For PROD and FORM, diallel analysis proved to be efficient in studying GCA effects. Cultivar Piramoita (group I) and accessions BGH-4360 and BGH-5253 (group II) showed positive values for GCA, suggesting that these parents possess a higher frequency of favorable alleles for these two traits. Significance in SCA effects was also verified, highlighting the crossing Piramoita x BGH-4360, for PROD, indicating that this combination is the most promising for breeding purposes.

No abstract

At initial breeding stages, using a replicated check design is a viable alternative to reduce experimental field area as well as financial and operational costs. In this situation, spatial modeling could act to increase prediction accuracy of plant genotypic values. The objectives of this study were to demonstrate how spatially adjusted models can be used to reduce experimental error and how to compare statistical models in order to identify the best model for accurate genotype selection. For this purpose, we assessed 200 F 3:4 tomato families for their resistance to Phytophthora infestans isolates. NC1CELBR, NC25P, and the cultivar Santa Clara were used as checks. Under field conditions, plants were inoculated with P. infestans isolates and scored according to their level of disease severity. Nine statistical models were adjusted to estimate family genotypic values. The selection of the fittest model was based on residual variance values, accuracy, Akaike and Bayesian information criteria, and the maximum likelihood ratio test. We observed spatial patterns within the experimental field area. Spatial modeling decreased error, which is indicated by the better experimental variation distribution. Residual variance decreased, while genotypic variance increased ∼10% when spatial analysis was used. Spatial analysis improved selection accuracy by 19% compared with the traditional analysis. Therefore, we recommend incorporating spatial modeling into data analysis in breeding trials for disease resistance because it can provide higher gains from selection compared with traditional modeling approaches, depending on the experimental condition.

<p class="Default"><em><span>Oeceoclades maculata</span></em><span> (Lindl.) Lindl. pertence &agrave; fam&iacute;lia Orchidaceae e, como as demais plantas dessa fam&iacute;lia, necessita da intera&ccedil;&atilde;o com fungos micorr&iacute;zicos para que a germina&ccedil;&atilde;o de suas sementes ocorra na natureza. V&aacute;rias popula&ccedil;&otilde;es de <em>O. maculata</em> foram encontradas no munic&iacute;pio de Rio Parana&iacute;ba, o qual est&aacute; inserido no bioma do Cerrado. N&atilde;o h&aacute; relatos de estudos da associa&ccedil;&atilde;o micorr&iacute;zica para plantas deste bioma. Este trabalho teve como objetivo caracterizar a associa&ccedil;&atilde;o micorr&iacute;zica de <em>O. maculata </em>a partir do isolamento, caracteriza&ccedil;&atilde;o morfol&oacute;gica e identifica&ccedil;&atilde;o dos fungos micorr&iacute;zicos associados a seu sistema radicular e testar a compatibilidade dos isolados na germina&ccedil;&atilde;o de <em>Cattleya walkeriana</em> Gardner, <em>Dendrobium nobile</em> Lindl., <em>O. maculatta</em> e <em>Sophronitis cernua </em>Lindl., orqu&iacute;deas encontradas no Cerrado. Isolou-se 44 fungos, que foram organizados em nove morfotipos e identificados como <em>Fusarium sp</em>., <em>Rhizoctonia-like</em> e Basideomicetes. Alguns destes fungos se mostraram eficientes na germina&ccedil;&atilde;o, podendo ser utilizados na produ&ccedil;&atilde;o de mudas destas plantas.</span></p>