Since 1984, the ‘Chilero’ spring wheat line developed by CIMMYT has proven to be highly resistant to leaf rust and stripe rust. Amid efforts to understand the basis of resistance of this line, a recombinant inbred line (RIL) population derived from a cross between Avocet and Chilero was studied. The parents and RILs were characterized in field trials for leaf rust and stripe rust in three locations in Mexico between 2012 and 2015 and genotyped with DArT-array, DArT-GBS, and SSR markers. A total of 6,168 polymorphic markers were used to construct genetic linkage maps. Inclusive composite interval mapping detected four colocated resistance loci to both rust diseases and two stripe rust resistant loci in the Avocet × Chilero population. Among these, the quantitative trait locus (QTL) on chromosome 1BL was identified as a pleotropic adult plant resistance gene Lr46/Yr29, whereas QLr.cim-5DS/QYr.cim-5DS was a newly discovered colocated resistance locus to both rust diseases in Chilero. Additionally, one new stripe rust resistance locus on chromosome 7BL was mapped in the current population. Avocet also contributed two minor colocated resistance QTLs situated on chromosomes 1DL and 4BS. The flanking SNP markers can be converted to breeder friendly Kompetitive Allele Specific PCR (KASP) markers for wheat breeding programs.

El objetivo de este estudio fue caracterizar los estomas de cinco especies de vainilla. Durante el año 2012 se tomaron muestras de hoja de Vanilla planifolia G. Jackson, V. pompona Schiede, V. inodora Schiede, V. insignis Ames y V. odorata Presl, del banco de germoplasma de vainilla de la Benemérita Universidad Autónoma de Puebla. Se obtuvo el tamaño de estomas al considerar el largo y ancho de estos, índice y número estomático de la parte abaxial y adaxial de la hoja, en un diseño de bloques completos al azar con tres repeticiones. V. pompona Schiede y V. inodora Schiede presentaron mayor índice estomático con 8713 y 8246 estomas por mm2, respectivamente, seguido por V. odorata Presl con 4412 estomas por mm2. V. insignis Ames y V. planifolia G. Jackson tuvieron el menor índice estomático con 2968 y 1378 estomas por mm2, respectivamente, en la superficie abaxial de la hoja, diferencias que fueron estadísticamente significativas (p≤ 0,05). Por la posición de los estomas en la hoja, V. planifolia G. Jackson y V. pompona Schiede se pueden considerar hipoestomáticas por presentar estomas solamente en la parte abaxial de la hoja. V. insignis Ames, V. inodora Schiede y V. odorata Presl se pueden considerar anfiestomáticas por presentar estomas en la parte abaxial y adaxial de la hoja. V. inodora Schiede presentó estomas más pequeños en comparación con las demás especies, característica importante para ser integrada en el mejoramiento genético del género Vanilla, al considerar el cambio climático, donde el aumento de temperatura y disminución de la precipitación requieren de genotipos con mayor eficiencia en el uso de agua.

Commercial tomato (Solanum lycopersicum L.) hybrids can be a good germplasm for obtaining new tomato inbred lines. The present study was aimed to investigate the stability of commercial F₁ hybrids under climatic conditions of highlands, to estimate genetic parameters, and evaluate the breeding potential of F₁ hybrids based on the agronomic performance of its F₃ progeny. We employed a breeding scheme based on pedigree selection for the obtainment of 49 F₃ families. Significant differences were found in most of the traits evaluated in both F₁ and F₃ generations, while in the F₂ population only one variable showed significant differences. Heritability ranged from 0.07 to 0.29 for F₁, and from 0.16 to 0.45 for F₃. Most of the F₁ hybrids exhibited values of stability across seasons in at least one trait. However, ‘Loreto’ and ‘Reserva’ only exhibited a high stability for yield. Genetic gains ranged from -8.40 to 72.95. Yield per plant was the traits with the highest gain. Based on genetic gains obtained by the F₃ progeny, we concluded that ‘Cid’, ‘Espartaco’ and ‘Loreto’ have a high breeding potential for yield and other traits, which could be exploited by public tomato breeding programs.

Genomic selection is considered to be an important tool in plant breeding programs. However, its application in the earliness of tomato (Solanum lycopersicum L.) has not been studied. The objective of the present study was to evaluate the prediction performance of six statistical models for six quantitative characteristics related to earliness in tomato. The study used phenotypic and genotypic data belonging to an F₂ population consisting of 172 tomato plants. Simple sequence repeat (SSR) markers were obtained using genotypic information, and the genomic values were estimated by the following six different statistical models: Bayesian Lasso (BL), Bayesian ridge regression (BRR), BayesA, BayesB, BayesCπ, and reproducing kernel Hilbert spaces (RKHS) regression. The correlation values ranged from 0.17 to 0.57. The highest association values were found in days to flowering of the third inflorescence and 1000-seed weight, which were greater than 0.5. In general, all the models performed in a similar manner because only slight differences were observed among the correlation values. Specifically, BL, BayesB, and RKHS exhibited the highest Pearson correlation values for most traits. According to the results, genomic selection could be a useful tool to support tomato breeding focused on earliness.