Morphological Characteristics, Fruit Qualities and Evaluation of Reproductive Functions in Autotetraploid Satsuma Mandarin (Citrus unshiu Marcow)

The morphological characteristics and fruit quality of an autotetraploid plant selected from nucellar seedlings of Satsuma mandarin (Citrus unshiu Marcow.) were investigated. Additionally, in order to evaluate the reproductive potential of male and female gametes of the tetraploid Satsuma mandarin, reciprocal crosses with diploid cultivars were also carried out. The tetraploid had significantly thick and round leaves, as compared to those of the diploid Satsuma mandarin. The sizes of the flowers and pollen grains of the tetraploid were significantly larger than those of the diploid. Pollen fertility of tetraploid was high compared with that of the diploid. The tetraploid produced seedless fruits. The fruit weight of the tetraploid was equal to that of the diploid. Compared to the diploid fruits, the tetraploid fruit had less sugar contents and more organic acid contents. Although the tetraploid fruits showed similar traits to other Citrus tetraploids such as thick and hard peels, the tetraploid had a higher content of carotenoids in the flavedo than the diploid, and the rind color of the tetraploid was much better. In the reciprocal crosses between the tetraploid Satsuma mandarin and diploid cultivars, some seeds were obtained, and triploid progenies were obtained in all cross combinations.

Integrated Analysis of Cecal Microbiome and Metabolome Revealed Different Inflammatory Reponses to Salmonella Enterica Serovar Enteritidis Between Reciprocal Crosses of Chicken

Background: Salmonella enterica serovar Enteritidis (S. Enteritidis) bacteria can colonize intestinal tract of chicken and transmit to humans, while the intestinal microbiota are resistant to their colonization. Our knowledge of the interplay between host, pathogen and microbiota is scarce, particularly in context of different genetic background of the host, such as the reciprocal cross.Results: Comprehensive analysis of microbiome and metabolome showed that 23.4% of genera and 11.6% of metabolites in the Cross, and 17.2% of genera and 25.1% of metabolites in the Reverse-cross were altered (P<0.05) in response to Salmonella infection. In comparison of the reciprocal crosses, all the co-differential genera and 73.1% of the co-differential metabolites were opposite in alteration trend. Phenylpropanoids and lipids were increased significantly in the Cross and in the Reverse-cross, respectively.Conclusions: A more extensive inflammatory response to S. Enteritidis might be triggered in the Reverse-cross than in the Cross, and the regulatory modes were different. The Reverse-cross upregulated pro- and anti-inflammatory factors simultaneously, while the Cross was aided with the phenylpropanoids produced by intestinal bacteria.

Combining Ability for Quantitative Traits Under Normal And Heat Stress Conditions in Maize (Zea Mays L.)

Investigation was carried out to ascertain the genetic architecture for heat tolerance and yield components from diallel crosses in maize (Zea mays L.). The combining ability in both the normal and heat stress conditions revealed highly significant mean squares due to general combining ability (GCA) and specific combining ability (SCA) in both the direct and reciprocal crosses for all the characters except for anthesis-silking interval in normal condition of the reciprocal crosses. Estimate of components of variance for 13 characters revealed higher SCA variance than that of GCA and reciprocal crosses for all the characters. CML 411 was good general combiner for grain yield in both the conditions, whereas, CML 306 and CML 307 were good general combiners in heat stress condition, and CML 164, CML 304 and CML 305 were average general combiners in normal condition. On the basis of high yield, high SCA and at least high GCA of seed parent, the CML 411*CML 305 and CML 411*CML 307 were identified as promising hybrids for normal and heat stress conditions, respectively. Bangladesh J. Bot. 50(3): 659-669, 2021 (September)

Hotter chili peppers by hybridisation: heterosis and reciprocal effects

The selection of pure lines followed by crosses to create superior hybrids is one of the oldest strategies in crop breeding. However, in domesticated species of the Capsicum genus hybrid breeding has lagged, in part due to a lack of detailed information about the phenotypic and metabolic consequences of hybridization. Here, we performed reciprocal crosses between four inbred varieties of two species of cultivated C. chinense (cv. Habanero and Biquinho) and C. annuum var. annuum (cv. Jalapeño and cv. Cascadura Ikeda). These varieties were specifically selected for their highly divergent traits, including plant growth habit, fruit size, shape and pungency: Habanero and Jalapeño peppers are highly pungent forms, particularly popular in Mexico. The Biquinho cultivar of C. chinense and the Cascadura Ikeda bell pepper are traditional sweet cultivars from Brazil. From the parental genotypes and from the progeny of the reciprocal crosses, we measured 31 phenotypic traits, including plant growth, and yield, 32 fruit shape parameters, and 50 fruit pericarp and placenta metabolites, including capsaicinoids. We found large differences for agronomic and metabolic traits between the genotypes, including heterosis for pungency and reciprocal effects for agronomic traits. We also show that the strong association between fruit shape and pungency can be broken in intraspecific hybrids, paving the way for the precision breeding of novel varieties.

High Incidence of Related Wolbachia across Unrelated Leaf-Mining Diptera

The maternally inherited endosymbiont, Wolbachia pipientis, plays an important role in the ecology and evolution of many of its hosts by affecting host reproduction and fitness. Here, we investigated 13 dipteran leaf-mining species to characterize Wolbachia infections and the potential for this endosymbiont in biocontrol. Wolbachia infections were present in 12 species, including 10 species where the Wolbachia infection was at or near fixation. A comparison of Wolbachia relatedness based on the wsp/MLST gene set showed that unrelated leaf-mining species often shared similar Wolbachia, suggesting common horizontal transfer. We established a colony of Liriomyza brassicae and found adult Wolbachia density was stable; although Wolbachia density differed between the sexes, with females having a 20-fold higher density than males. Wolbachia density increased during L. brassicae development, with higher densities in pupae than larvae. We removed Wolbachia using tetracycline and performed reciprocal crosses between Wolbachia-infected and uninfected individuals. Cured females crossed with infected males failed to produce offspring, indicating that Wolbachia induced complete cytoplasmic incompatibility in L. brassicae. The results highlight the potential of Wolbachia to suppress Liriomyza pests based on approaches such as the incompatible insect technique, where infected males are released into populations lacking Wolbachia or with a different incompatible infection.

Genetic Resources of The Universal Flavor, Vanilla

Commercially cultivated vanilla (V. planifolia) is native to Mexico and its cultivation and breeding programmes face major bottlenecks. This study reports presence of important agronomic characters in two important and endangered species of Vanilla, V. aphylla and V. pilifera, indigenous to India. V. aphylla was tolerant to Fusarium wilt and had longer flower life than the cultivated vanilla. V. pilifera flowers were fragrant, showed signs of insect pollination and had large fruit size. The species were amenable to interspecific hybridization and successful reciprocal crosses were done. Sequence similarity studies indicated the clustering of leafy and leafless species separately.

Assessment of Maternal Effects and Genetic Variability in Resistance to Verticillium dahliae in Olive Progenies

The use of genetic resistance is likely the most efficient, economically convenient and environmentally friendly control method for plant diseases, as well as a fundamental piece in an integrated management strategy. This is particularly important for woody crops affected by diseases in which mainly horizontal resistance mechanisms are operative, such as Verticillium wilt, caused by Verticillium dahliae. In this study, we analyzed the variability in resistance to Verticillium wilt of olive trees in progenies from five crosses: ‘Picual’ × ‘Frantoio’, ‘Arbosana’ × ‘Koroneiki’, ‘Sikitita’ × ‘Arbosana’, ‘Arbosana’ × ‘Frantoio’ and ‘Arbosana’ × ‘Arbequina’ and their respective reciprocal crosses. Additionally, seedlings of ‘Picual’ and ‘Frantoio’ in open pollination were used as controls. In October 2016 and 2018, the fruits were harvested, and seeds germinated. Six-week-old seedlings were inoculated by dipping their bare roots in a conidial suspension of V. dahliae, and disease progress in terms of symptom severity and mortality was evaluated weekly. Additionally, seedling growth was evaluated every two weeks. At the end of the experiment, no significant differences were found for any of the assessed parameters when reciprocal crosses were compared. These results suggest that there is no maternal or paternal effect in regard to the heritability of resistance. In addition, this study identifies the best crosses for obtaining the highest number of resistant genotypes, highlighting the importance of the selection of specific cultivars to optimize the breeding process.

Sporogenesis in F1 hybrids from the crosses between common wheat and lines with introgressions from Amblyopyrum muticum

Hybridization of wheat lines comprising fragments of alien genetic material (introgression) with common wheat cultivars is effective and widespread means of transferring alien genes into genomes of modern wheat cultivars, and remains the main method of expending genetic pool of common wheat using genes of wild relatives. Success of such transfer depends on the processes of sporo- and gametogenesis in F1 hybrids, therefore cytological assessment of this processes is obligatory. Stages of meiosis and microgametogenesis were studied on cytological preparations of spikes of F1 hybrids from reciprocal crosses of common wheat cultivars and wheat lines of introgression origin with alien genetic material from wheat wild relative Amblyopyrum muticum. Sporogenesis in F1 hybrids occurs with disorders in both male and female sexual areas. Instead of 21 closed bivalents chromosome configurations in maximal association of chromosomes in M1 PMC could contain up to 8 open bivalents, up to 12 univalents, including three- and quadrivalents. In A1 lagging chromatids were observed, and up to 5 micronuclei per cell were registered in tetrads. Quantitative characteristics of chromosome associations in M1 PMC did not differ for hybrids obtained using introgression lines as female (direct crossing) and male (reverse crossing) cross components. The difference between reciprocal crosses was detected only for the quantity of cells in tetrads with different quantity of micronuclei. F1 hybrids from direct crosses had smaller portion of cells without micronuclei, and more cells with 1-3 micronuclei compared to hybrids of reverse crosses.