Wybrane aspekty biologii rozwoju wegetatywnego i generatywnego oberżyny (Solanum melongena L.) w uprawie polowej

Agnieszka Sękara

Abstract

Eggplant (Solanum melongena L.), called a 'king of vegetables' in subtropical regions of Asia, belongs to the most important crops in the word. The largest producers are China (17 million tons per year) and India (9 m. t). In Europe, over a half of the output comes from Turkey (924 thousand tons); top producers are also round Italy, Spain and Romania. Eggplant has grown in popularity in Poland, too. The vegetable has been cultivated in unheated plastic tunnels and, for a few years, in the open field, but it is still treated as a species with extremely high thermal requirements. Therefore, the aim of this study was to investigate the development and yielding of eggplant in field production. Special consideration was given to flowering biology. The research concentrated on the effects of chilling stress on chosen parameters of plant development at a transplant stage, as well as the relationship between microclimatic conditions in the field and the physiological condition of plants, the course of flowering, the amount of yields, and the chemical composition of fruits. Eggplant 'Epic F,' hybrid was used in two experiments carried out in 2005-2007 in the growing chambers, greenhouses and field experimental station of the University of Agriculture in Krakow, Poland. Experiment 1 examined the influence of low temperatures on the morphological, chemical and physiological aspects of the development of transplants. Six-week-old transplants were placed for two weeks in growing chambers under temperature regimes of 8, 12, and 16°C. Transplants grown in a greenhouse at 20°C were used as a control. After chilling, the morphology of plants (height, weight, number of leaves, area of leaves, leaf area index, leaf area ratio), their chemical composition (dry matter, N, P, Mg, K, Ca, Fe, chlorophyll a, and b), and the cross-section of flower buds and shoot apical meristems were investigated. In the next part of Experiment 1, the chilled and control transplants were planted in field conditions to determine the course of phenological phases, and the amount and quality of yield. Experiment 2 investigated the development and yielding of eggplant in field cultivation. Eight-week-old transplants were planted in two treatments: (i) control treatment, and (ii) treatment with the microclimate modified by means of wind barriers from sweet corn 'Trophy F1'. Seeds were sown at the beginning of March, and transplants were planted at the beginning of May. Nutrients were supplemented to the following level (mg - dm-3): N - 100, P - 90, K - 220, Ca - 1100, Mg - 70. Each year, fourteen series of analyses were performed on the following dates: 10, 20 and 30 May; 10, 20 and 30 June; 10, 20 and 30 July; 10, 20 and 30 August; 10 and 20 September (± 2 days). Each analysis covered plant morphology (height, weight, number of leaves, area of leaves, leaf area index, leaf area ratio), chemical composition (dry matter, N, P, Mg, K, Ca, Fe, chlorophyll a, and b), biology of flowering (number of flowers with long-, medium- and short-style pistil, number of fruits set by flowers with different types of pistil, and the effectiveness of fruit setting, germination of pollen on stigmas, growth of pollen tubes, and fertilisation of ovules), biology of fruiting (early, total and marketable yield, chemical composition of fruits: dry matter, insoluble fibre, P, Mg, K, Ca, Fe, Cu, Mn, Zn). A study of the growth and development of eggplant under the field conditions of Poland contributed to the knowledge of the species behaviour in less favourable climatic conditions. Treating eggplant transplants with low temperature (up to 8°C) made it possible to control their morphology without putting them at risk of chilling damage which would negatively influence the subsequent plant development. The course of the vegetative and generative development of plants in the field depended on microclimatic conditions. Using wind barriers of sweet corn to shelter the eggplant field led to changes in temperature and humidity. Although the mean temperature did not increase, but the daily and nightly temperature fluctuations were reduced. Such modification of microclimate resulted in advancing the flowering and fruiting phases, and increasing the early yield. The course of flowering (number and type of flowers set in a defined period) varied within the growing season: periods of intense flowering and fruit setting alternated with those of weak flowering and intense growing of early-set fruits. Flowers exhibited heterostyly with dominating long-style pistils. Flowers with long- and medium-style pistils set fruits more effectively than the short-style ones. Fruit setting in the field was most intensive in July. Based on these results, new recommendations on plant individual strategy can be made with regard to the proportion of particular types of flowers in ontogeny development. Heterostyly in eggplant was considered to be a transition stage to andromonoecy, which physiologically prefers male flowers in periods when early-set fruits ripe. The novelty of the present investigations consisted in characterising the pollination and fertilisation biology of eggplant in field cultivation, which provided a basis for explaining the causes of the lower fertility of flowers with short-style pistils. The number of pollen tubes and fertilised ovules was greatest in flowers with long-style pistils. The formation of the ovules and their position in the placenta of flowers with long-, medium-, and short-style pistils were similar. Significantly smaller number of pollen tubes and fertilised ovules in the placenta of flowers with short-style pistils resulted from a smaller style size and spatial distance between the stigma and anthers, which made pollination difficult. An analysis of the eggplant yielding in the field conditions in Poland provided evidence to suggest that such type of production should be popularised. The mean marketable yield of 'Epic F1' hybrid amounted to 4.2 kg • m-2, and the early yield (first four harvests) constituted 13.5% of the former. Field cultivation made it possible to obtain eggplant yields of very good quality, with 86% and 10%, respectively, of 1st and 2nd class fruits in the total yield. The eggplant fruits had a high biological value, which manifested itself, among others, in the high contents of insoluble fibre (0,97 g • 100 f.m.) and chemical elements (in mg 100 g-1 f.m.): potassium — 227.0, phosphorus — 20.23, calcium — 20.60, magnesium — 12.12, iron — 0.436, manganese —0.106, copper — 0.101 and zinc — 0.225; with the dry matter content of 7.62 g • 100 The high chilling tolerance of eggplant and the possibility of cultivating this species in the field under the climatic conditions of Poland offer prospects for future basic and implementation researches.
Other language title versionsBiology of the vegetative and generative development of eggplant (Solanum melongena L.) in field production: chosen aspects
Book typeMonograph
Other categories ROZPRAWA_HABILITACYJNA
Author Agnieszka Sękara (UAK)
Agnieszka Sękara,,
- University of Agriculture in Krakow
PublisherUniwersytet Rolniczy im. Hugona Kołłątaja w Krakowie, MNiSW [80]
Publishing place (Publisher address)Kraków
Issue year2010
Book series /Journal (in case of Journal special issue)Zeszyty Naukowe Uniwersytetu Rolniczego im. Hugona Kołłątaja w Krakowie. Rozprawy, ISSN 1899-3486, (0 pkt)
Vol459
No336
Pages101
Publication size in sheets7
Languagepl polski
Score (nominal)20
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