Genetic Variation of a Lentil (Lens culinaris) Landrace during Three Generations of Breeding

Genetic differentiation between 40 lentil genotypes was tested using molecular markers. The genotypes were produced from a Greek landrace of commercial interest via the honeycomb breeding methodology, i.e., single-plant selection in the absence of competition, across three successive pedigree generations. The selected genotypes from each generation were examined for genetic relationships using 15 SSR molecular markers with HRM analysis. As expected, low variation among consecutive generations at the level of 2.5–7.7% was detected. Analysis of molecular variance (AMOVA) revealed that partitioning of this variation was at higher percentage within each generation’s population than between them. Population structure analysis indicated that ongoing selection could effectively shift the allelic composition in each generation. The applied honeycomb breeding methodology that effectively improved progeny yield and seed quality increased the percentage of favorable alleles altering allelic composition but not eliminating genetic variation of the breeding population.

Reproduction of Ooencyrtus submetallicus (Hymenoptera: Encyrtidae) and Trissolcus sp. aff. urichi (Hymenoptera: Scelionidae) in Eggs of Nezara viridula (Hemiptera: Pentatomidae) of Different Ages

The study of the interaction between parasitoid and host, especially the age of these organisms, is an important step towards the implementation of biological control programs. Therefore, we investigated the performance of Ooencyrtus submetallicus (Hymenoptera: Encyrtidae) and Trissolcus sp. aff. urichi (Hymenoptera: Scelionidae) parasitizing eggs of Nezara viridula (Hemiptera: Pentatomidae), considering different ages of the parasitoids and the host. We performed four laboratory bioassays: two using females of O. submetallicus and Trissolcus sp. aff. urichi at 24, 48, 72, 96, 120, or 144 hours of age exposed to parasitism in N. viridula eggs (24 h) and two trials with N. viridula eggs at 24, 48, 72, 96, 120, or 144 hours exposed to the parasitism of O. submetallicus and Trissolcus sp. aff. urichi (24 h). We evaluated the percentage of parasitism and emergence, life cycle length, progeny, sex ratio, and the longevity of the parasitoids. The parasitism of O. submetallicus in N. viridula eggs was influenced by the age of the parasitoid, 120 hours being the minimum to obtain better parasitism. From this age on, there is interference in the longevity of the progeny. Trisolcus sp. aff. urichi, at all ages, parasitized N. viridula eggs relatively well, but with almost no emergence of the parasitized eggs. Females of O. submetallicus parasitized and developed in eggs of N. viridula of all ages. Females of Trissolcus sp. aff. urichi parasitized their host, but there was barely any emergence. These pieces of information regarding the breeding methodology contribute to the implementation of new protocols for the multiplication of these parasitoids in the laboratory, and later, their release in the field.

Tools for transforming wheat breeding: genomic selection, rapid generation advance and database-based decision support.

This chapter discusses the increased implications in the current breeding methodology of wheat, such as rapid evolution of new sequencing and genotyping technologies, automation of phenotyping, sequencing and genotyping methods and increased use of prediction and machine learning methods. Some of the strategies that will further transform wheat breeding in the next few years are also presented.

Breeding red clover for improved persistence in Chile: a review

The main limitation of red clover (Trifolium pratense L.) worldwide including in Chile is the lack of persistence related to the high mortality of plants due to a complex of biotic and abiotic factors. We have demonstrated in various trials in Chile that red clover plant population is highly correlated with forage yield once the plant population has dropped to a certain level, from the second or third season onward, depending on the environment of evaluation. We have also found that in the south of Chile, among the biotic and abiotic factors affecting red clover survival, the curculionid Hylastinus obscurus (Marsham) is the main deleterious factor. However, because persistence is a complex trait, we have used a practical approach in our breeding program. We selected for general adaptability under field conditions and used a modified among and within half-family selection methodology, evaluating at the same time families as swards and spaced plants. This breeding methodology and strategy have yielded reasonable genetic gains since we started our breeding program in 1989 at INIA Carillanca, Chile. Since then, we have conducted five cycles of recurrent selection, and two cultivars have been released to replace the old cultivar, Quiñequeli INIA. These are Redqueli INIA and, more recently, Superqueli INIA. Depending on location and trial, average forage yield of the newest cultivar Superqueli INIA has been 23–69% higher than Quiñequeli INIA and 5–36% higher than Redqueli INIA; this difference increases in the third and fourth seasons. Superqueli INIA had four times the yield of Quiñequeli INIA in the fourth season. Therefore, the average realised genetic gain has been 0.4–2.6% per year, depending on location, showing the effectiveness of the breeding methodology and approach used.