Apples (Malusdomestica Borkh) are prone to preharvest fruit drop, which is more pronounced in ‘Honeycrisp’. Hexanal is known to improve fruit retention in several economically important crops. The effects of hexanal on the fruit retention of ‘Honeycrisp’ apples were assessed using physiological, biochemical, and transcriptomic approaches. Fruit retention and fruit firmness were significantly improved by hexanal, while sugars and fresh weight did not show a significant change in response to hexanal treatment. At commercial maturity, abscisic acid and melatonin levels were significantly lower in the treated fruit abscission zone (FAZ) compared to control. At this stage, a total of 726 differentially expressed genes (DEGs) were identified between treated and control FAZ. Functional classification of the DEGs showed that hexanal downregulated ethylene biosynthesis genes, such as S-adenosylmethionine synthase (SAM2) and 1-aminocyclopropane-1-carboxylic acid oxidases (ACO3, ACO4, and ACO4-like), while it upregulated the receptor genes ETR2 and ERS1. Genes related to ABA biosynthesis (FDPS and CLE25) were also downregulated. On the contrary, key genes involved in gibberellic acid biosynthesis (GA20OX-like and KO) were upregulated. Further, hexanal downregulated the expression of genes related to cell wall degrading enzymes, such as polygalacturonase (PG1), glucanases (endo-β-1,4-glucanase), and expansins (EXPA1-like, EXPA6, EXPA8, EXPA10-like, EXPA16-like). Our findings reveal that hexanal reduced the sensitivity of FAZ cells to ethylene and ABA. Simultaneously, hexanal maintained the cell wall integrity of FAZ cells by regulating genes involved in cell wall modifications. Thus, delayed fruit abscission by hexanal is most likely achieved by minimizing ABA through an ethylene-dependent mechanism.
Increasing awareness of heart health and disease prevention has led consumers to more proactive grocery food choices. Fibre and its associated health benefits remains an important area of research given the current interest in food, nutrition, and health. To position the potato as a good source of fibre, breeding efforts have focused on developing cultivars and germplasm with high fibre content. The current study examined eight elite potato clones and four commercial cultivars (checks) across six environments (three locations over two years) for their total dietary fibre (TDF), neutral detergent fibre (NDF), and soluble fibre (SF) content. Genotype by environment interaction (GEI) and stability analysis were conducted with SAS and GGE Biplot software. Significant genotypic (G), environmental (E) and GEI effects were found. The six environments differed in temperature and moisture levels, which were linked to levels of NDF and TDF. Some genotypes had high levels of stability for fibre content. GGE biplot analysis found no significant mega-environments for fibre components. Two elite clones (CV96044-3 and F05081) were identified as high fibre sources (13.3 and 14.4 %, respectively) compared to the other elite clones and commercial cultivars (e.g., Russet Burbank: 11.7 %). These lines may also be suitable as parents with high fibre and stability to breed into backgrounds with other desirable qualities.
1 May 2005 in Journal of the American Society for Horticultural Science
The potential of using Fragaria vesca L. as a bridge species for interspecific hybridization to F. nilgerrensis Schlect , F. nubicola Lindl ., F. pentaphylla Losinsk, and F. viridis Duch . was investigated using a wide germplasm base of 40 F. vesca accessions. This study was successful in producing many hybrids between F. vesca and other diploid species indicating its value as a bridge species. Of the species used as males, F. nubicola, F. pentaphylla , and F. viridis accessions were more successful, averaging 8 to 16 fruit and 16 to 25 seeds/fruit. It was most difficult to obtain hybrids with F. nilgerrensis , which had only three seeds per fruit. Differences among pollen donors were minimal when hybrid seeds were germinated in vitro . For different species combinations, 75% to 99% of seeds had embryos and 77% to 89% of these embryos germinated. The lack of significant differences in crossability variables among the four F. vesca subspecies [i.e., ssp. americana (Porter) Staudt , ssp. bracteata (Heller) Staudt , ssp. vesca L., and ssp. vesca var. semper-florens L.] demonstrated the similarity between these species and the strong potential for gene flow between F. vesca and other diploid species. As European and North American F. vesca subspecies are not sufficiently divergent to differ in interspecific hybridization, F. vesca may be a younger species rather than an older progenitor species.