Selección de parentales para obtención acelerada de variedades de patata (Solanum tuberosum L.) con aptitud para procesamiento industrial mediante la aplicación de un modelo genético dialélico

Resumen

With the aim of evaluating several advanced breeding clones and varieties of potato (S. tuberosum) for their ability to transmit traits of interest to their progenies, a diallelic assay has been developed for this tetraploid and vegetatively propagated species, with six parents crossed in a diallel group, Griffing’s model I, method 4, since the reciprocals were not included. A set of progenies was obtained and tested at various locations for 3 years. Data from field trials focused on agronomic traits, plant maturity and yield were collected, and tuber quality analysis were performed, focused on the specific gravity of the tubers and chip color. The data collected were analyzed according to an Anova model for several locations and a diallel analysis, to determine the estimates of the general combining ability (GCA) and the specific combining ability (SCA) of the different parents and crosses respectively, for each trait. An important environmental effect was found for all traits, although for each character the significant effects detected varied. For plant maturity, a significant effect of the genotype factor was found, and the variance partition determined the action of additive and non-additive genes, since both GCA and SCA were significant. For yield trait however, no genetic effects were detected, nor were there significant interactions. Regarding quality traits, for specific gravity of the tubers, a significant effect of the genotype factor was found, and the diallel analysis determined that it was purely additive effects, detecting that the GCA was significant but not the SCA, without finding interactions. Regarding chip color, the Anova detected a significant genotype x environment interaction, and the diallel analysis determined that it was due to both the interaction of GCA x environment and SCA x environment, which indicates an important environmental effect for this trait. The estimates of the general combining ability for plant maturity agronomic trait indicate that the variety Atlantic is able to transmit earliness to its progenies, while the advanced clones 95P17-3 and 95P87-4 generate significantly later progenies. In terms of yield, however, no parent with the capacity to improve the yield of the progenies was found. In terms of quality traits, the Atlantic variety has the highest GCA estimate for specific gravity, so it is a good variety that transmits its quality trait, while clone 95P87-4 and the variety Caesar obtain the highest negative estimates of the GCA and cannot be considered as good parents for specific gravity. For the quality trait chip color, the interactions do not allow to determine the capacity of this group of parents to transmit this trait to the progenies, since the environmental effect modifies the genetic expression of the trait. These results confirm that a strict clonal selection based on tuber quality and yield traits in the first generations of the program is not recommended due to the strong influence of the environment on these traits. An adequate number of trials in selected environments should be carried out to assess genotype x environment interactions, especially for traits related to quality. Progeny testing through diallel analysis has been a very effective tool to obtain results on the performance of the parental genotypes and confirms that an early assessment of the possible parents of the program in different environments should be carried out to identify those genotypes able to transmit their positive traits through crosses to their offspring, and to know their ability to adapt. The main objectives of this work have been fulfilled, since the most suitable varieties have been selected to obtain descendant clones with good quality for industrial processing, and the environmental and genetic components of potato productivity and quality traits have been analyzed.