Eggplant (Solanum melongena L.) is a warm climate crop. Its cultivation extends to temperate regions where low temperatures can affect the course of the generative phase, which is primarily sensitive to abiotic stress. The novelty of the present investigation consisted of characterising the heterostyly, pollination, and fertilisation biology of eggplants in field cultivations, which provided a basis for explaining the effect of a protective biostimulant on these processes. We aimed to investigate the flowering biology of three eggplant hybrids treated with Göemar BM-86®, containing Ascophylum nodosum extract, to determine the crucial mechanisms behind the increased flowering and fruit set efficiency and the final effect of increased yield. The flower phenotype (long, medium or short styled), fruit setting, and the number of seeds per fruit were recorded during the two vegetation periods. The numbers of pollen tubes and fertilised ovules in ovaries were evaluated during the generative stage of development to characterise the course of pollination and fertilisation for all types of flowers depending on the cultivar and biostimulant treatment. The expression of heterostyly depended on the eggplant genotype, age of the plant, fruit load, and biostimulant treatment. Domination by long-styled flowers was observed, amounting to 41%, 42%, and 55% of all flowers of “Epic” F1, “Flavine” F1, and “Gascona” F1, respectively. This flower phenotype contained the highest number of pollen tubes in the style and the highest number of fertilised ovules. The biostimulant had a positive effect on the flower and fruit set numbers, as well as on the pollination efficiency in all genotypes. Ascophylum nodosum extract could be used as an efficient stimulator of flowering and fruit setting for eggplant hybrids in field conditions in a temperate climatic zone.

Seaweeds are one of the important marine bioresources which are nowadays termed as eco-friendly stimulators of crop growth, stress tolerance, and yielding. In this review, we give an update of the current state of our understanding of the seaweed extracts (SWE) effects on the physiological alterations they induce in Solanaceae vegetables. SWE may provide a powerful and environmentally friendly approach to nutrient management. A pool of common bioactive molecules of SWE provides enhancement of the antioxidant machinery of treated plants providing balanced development, earlier flowering, and enhanced fruiting. The basic mechanisms of SWE action seem to be unspecific for tomato, pepper, and eggplant. They include accelerating growth, nutrient uptake, and photosynthesis performance, which can induce plant tolerance to adverse environmental conditions, improve flowering, fruit setting, and yield, and enhance nutritional quality of the crops. The mechanism of SWE action is complex because of multielement composition and cross-action between constituents.

Consumer demands regarding eggplant fruits are focused on perfect shape, color, and taste but nutritional and bioactive quality has also become important with rising awareness of food related health. On the other hand, producers value modern cultivars’ earliness, high-yielding, stress-tolerance, and high overall fruit quality. We attempt to link these two standpoints through combining modern hybrids cultivated in the open field of temperate climatic zone with biostimulant application to increase the dynamics of yielding and the quality of fruits. The aim of our research was the determination of the genotypic-dependent response of eggplant (Solanum melongena L.) to Ascophyllum nodosum standardized extract (Göemar BM-86) application in field conditions of Poland, with respect to the most important characteristics linked to yield quality and plant stress status. The early and total yield of investigated hybrids was affected by biostimulant application, and this dependence was confirmed statistically for most of the treatments. The increase of ‘Epic’ F1 and ‘Flavine’ F1 yield potential through Göemar BM-86 application was linked to higher fruit number harvested from the plants, while ‘WA 6020’ F1 led to greater fruit weight. Investigated hybrids responded differently to biostimulant treatment with respect to dietary and pro-health value of fruits. Generally, the content of soluble sugar, anthocyanins, and mineral elements as well as was antioxidant activity of fruits were positively affected by biostimulant application. This tendency was statistically confirmed for several experimental treatments. Presented results give a new perspective on seaweed-based biostimulants as elicitors of crop’s self defense mechanisms as well as modulators of fruit setting, productivity and bioactive compounds accumulation in eggplant.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

Seaweed extracts are widely used in agriculture as ecological focus substances applied to improve crop growth and quality. One of the primary benefits they bring is increased effectiveness of fruit setting as well as improved stress tolerance, essential for warm-climate crops cultivated in the nonoptimal environmental conditions of Northern and Central Europe. The aim of this study was a preliminary investigation of any genotype-dependent reaction of eggplant cultivars (<em>Solanum melongena</em>) to application of a standardized extract of the seaweed <em>Ascophyllum nodosum</em> (Göemar BM-86) under field conditions in Poland. The only statistically relevant result of this biostimulant was shown for cultivar ‘Flavine’ F₁, where it positively affected the early crop yield and the number of fruits per plant. Fruit quality attributes, including antioxidant activity, as well as selected mineral contents, increased as an effect of biostimulant spraying. This reaction was specific for the cultivars investigated, and it was confirmed by significant differences in the main effects between biostimulant and control treatments for almost all the properties measured. The use of this <em>A. nodosum</em> extract suggested that there could be an improvement in fruit yield and quality in selected eggplant cultivars under field conditions in the temperate climatic zone.