Hybrids Development between Greek Salvia Species and Their Drought Resistance Evaluation along with Salvia fruticosa, under Attapulgite-Amended Substrate

Aiming to obtain Salvia hybrids with ornamental value and high drought resistance, for xeriscaping, crossbreeding was made with Greek Salvia species. S. fruticosa and S. officinalis when used as seed parent were successfully crossed with S. pomifera ssp. pomifera, S. ringens and S. tomentosa, while when used as pollen parent it only succeeded between S. fruticosa and S. tomentosa. The growth of S. fruticosa and the four hybrids, S. officinalis × S. pomifera, S. officinalis × S. tomentosa, S. officinalis × S. ringens and S. fruticosa × S. ringens, selected for their ornamental traits, was evaluated under limited irrigation and modification of the substrate with attapulgite clay. The hybrids S. officinalis × S. ringens and S. officinalis × S. tomentosa developed a compact plant shape and most lateral shoots, desirable characteristics for potted plants and xeriscaping. All hybrids, especially S. officinalis × S. pomifera and S. officinalis × S. tomentosa, survived water stress better than S. fruticosa. Modification of the substrate with attapulgite, under limited irrigation, caused a decrease in the above ground/root biomass ratio in some hybrids and in S. fruticosa increased the dry weight of the root indicating increased drought resistance.

Volatile profiling of fruits of 17 mango cultivars by HS-SPME-GC/MS combined with principal component analysis

Headspace solid-phase microextraction combined with GC/MS (HS-SPME-GC/MS) is one of the strongest tools for comprehensive analysis of volatile compounds and has been used to analyze aromatic components of mango and investigate its varietal characteristics. In this study, profiling of aroma compounds in 17 mango cultivars, grown in the same green house to exclude the effect of environmental factors, was conducted and the patterns were subjected to principal component analysis (PCA) to identify the relationship between the aroma components and cultivars. Fifty-nine different volatile constituents were detected from the blends of these 17 mango cultivars. The cultivars were divided into four clusters using PCA based on the volatile components determined in the study. Aiko was found to mainly contain δ-3-carene and showed a composition more similar to its pollen parent, Irwin, than to its seed parent, Chiin Hwang No. 1.

Pollen fertility differences in the progenies obtained from a cross between eggplant (Solanum melongena L.) as a seed parent and eggplant cytoplasmic substitution lines as pollen parents

To the best of our knowledge, there is no report about pollen fertility of the progenies developed using eggplant (Solanum melongena L.) as a seed parent and eggplant cytoplasmic substitution lines as pollen parents. Pollen fertility of these progenies is very important to use as restorer line in the eggplant’s hybrid breeding program. In this study, pollen fertility was investigated for the progenies which were produced using S. melongena ‘Uttara’ as a seed parent and the eggplant cytoplasmic substitution lines as pollen parents. To assess pollen fertility, pollen stainability and in vitro germination ability were investigated. Although the nuclear and the cytoplasmic genome of the progenies were almost identical to eggplant ‘Uttara’, a clear difference was observed in the pollen fertility due to the difference in the pollen parents having different wild Solanum cytoplasms. The progenies produced using the functional cytoplasmic male sterile (CMS) lines as a pollen parent, whose cytoplasm donor were S. kurzii, S. violaceum and S. virginianum, showed pollen release type and high pollen fertility almost equal to eggplant ‘Uttara’. It is considered that the characteristics of these progenies were almost the same as eggplant. On the other hand, the progenies that produced using the fertility restored lines of the pollen non-formation type CMS lines as a pollen parent, whose cytoplasm donors were S. aethiopicum, S. anguivi and S. grandifolium, showed pollen release type and low pollen fertility, i.e., pollen staining ability was about 54% and pollen germination ability were about 35%. It is considered that the cause of this low pollen fertility was the incompatibility between the eggplant cytoplasm and the eggplant nuclear genome, which seems to be modified in the process of continuous backcrossing under the wild Solanum cytoplasms. It is suggested that complete nuclear substitution is difficult by continuous backcrossing with eggplant in the alloplasmic lines with S. aethiopicum, S. anguivi and S. grandifolium cytoplasm donors. Incompatibility between the normal eggplant cytoplasm and the modified eggplant nuclear genomes of the alloplasmic lines with S. aethiopicum, S. anguivi and S. grandifolium cytoplasms might be a cause for the low pollen fertility of the investigated progenies

Effects of Metaxenia on Stone Cell Formation in Pear (Pyrus bretschneideri) Based on Transcriptomic Analysis and Functional Characterization of the Lignin-Related Gene PbC4H2

The deposition of lignin in flesh parenchyma cells for pear stone cells, and excessive stone cells reduce the taste and quality of the fruit. The effect of metaxenia on the quality of fruit has been heavily studied, but the effect of metaxenia on stone cell formation has not been fully elucidated to date. This study used P. bretschneideri (Chinese white pear) cv. ‘Yali’ (high-stone cell content) and P. pyrifolia (Sand pear) cv. ‘Cuiguan’ (low-stone cell content) as pollination trees to pollinate P. bretschneideri cv. ‘Lianglizaosu’ separately to fill this gap in the literature. The results of quantitative determination, histochemical staining and electron microscopy indicated that the content of stone cells and lignin in YL fruit (‘Yali’ (pollen parent) × ‘Lianglizaosu’ (seed parent)) was significantly higher than that in CL fruit (‘Cuiguan’ (pollen parent) × ‘Lianglizaosu’ (seed parent)). The transcriptome sequencing results that were obtained from the three developmental stages of the two types of hybrid fruits indicated that a large number of differentially expressed genes (DEGs) related to auxin signal transduction (AUX/IAAs and ARFs), lignin biosynthesis, and lignin metabolism regulation (MYBs, LIMs, and KNOXs) between the CL and YL fruits at the early stage of fruit development. Therefore, metaxenia might change the signal transduction process of auxin in pear fruit, thereby regulating the expression of transcription factors (TFs) related to lignin metabolism, and ultimately affecting lignin deposition and stone cell development. In addition, we performed functional verification of a differentially expressed gene, PbC4H2 (cinnamate 4-hydroxylase). Heterologous expression of PbC4H2 in the c4h mutant not only restored its collapsed cell wall, but also significantly increased the lignin content in the inflorescence stem. The results of our research help to elucidate the metaxenia-mediated regulation of pear stone cell development and clarify the function of PbC4H2 in cell wall development and lignin synthesis, which establishes a foundation for subsequent molecular breeding.

Pollen gene flow and molecular identification of full-sib families in small and isolated population fragments of Gleditsia triacanthos L.

To analyze the utility of isolated remnant populations for full-sibling (full-sib) identification among open-pollinated single-tree progeny in the outcrossing and insect-pollinated tree Gleditsia triacanthos L. (honey locust), we performed paternity analyses in forest fragments from two geographic regions using nuclear microsatellites. The first plot (Butternut Valley population) comprised only 7 trees, and 552 seedlings from a single seed parent were characterized at nuclear microsatellites. A large number of putative pollen donors (59) were identified in kinship analyses, but their individual contributions to the progeny were highly variable. Kinship and paternity analyses identified 149 putative full-sibs for genetic mapping sired by an external (unsampled) pollen parent. To better assess the frequency of long-distance pollen dispersal, a total of 180 seeds were collected from 6 seed parents in another fragmented population. In both plots, contemporary pollen dispersal occurred generally from outside the plots (99.38% and 87.50%–100% at the Butternut Valley and Ames Plantation sites, respectively) and thus over very long distances (>12 000 m in the Ames Plantation) suggesting that in highly fragmented landscapes, insect pollinators of honey locust are likely very effective long-distance dispersers.