Effects of growth conditions of donor plants and in vitro culture environment in the viability and the embryogenic response of microspores of different eggplant genotypes

Abstract

Notwithstanding the importance of eggplant in global horticulture, doubled haploid production in this species is still far from being efficient. Although acknowledged to have a role in the efficiency of androgenesis induction, factors such as the growth conditions of donor plant or the in vitro culture environment have not been deeply explored or not explored at all in eggplant, which leaves room for further improvement. In this work, we investigated the effects of different in vivo and in vitro parameters on the androgenic performance of different eggplant genotypes, including two hybrids and a DH line. The in vivo parameters included the exposure of donor plants to different temperature and light conditions and to increased levels of boron. The in vitro parameters included the use of different concentrations of NLN medium components, sucrose and growth regulators, and the suspension of microspores at different densities. Our results showed that whereas greenhouse temperature variations or boron application did not to have a positive influence, greenhouse lighting influenced their viability, thereby conditioning the embryogenic response. Changes in different sucrose, salts and hormone levels had different effects in the genotypes studied, which correlated with their genetic constitution. Finally, we determined the best microspore density, different from that previously proposed. Our work shed light on the role of different factors involved in eggplant microspore cultures, some of them not yet studied, contributing to make microspore culture a more efficient tool in eggplant breeding.

Doubled Haploids in Eggplant

“…Indeed, the viability of eggplant microspores was found to be affected by the light intensity applied to donor plants, but not by slight (circa 6 °C) temperature changes [35]. Interestingly, the viability of eggplant microspores was not dependent on light intensity at the moment of excision of the floral buds, but it was influenced by the amount of light that donor plants were exposed to during the two days prior to excision [35]. Moreover, although microelements such as boron has been shown to increase pollen quality in pepper [43], the foliar application of boron at low doses produced no effects in the viability of eggplant microspores, and notably reduced it at high doses [35].…”

“…The first aspect that influences the embryogenic response of microspores is the conditions under which the donor plants have been cultured, which influences further viability of microspores to a large extent. Indeed, the viability of eggplant microspores was found to be affected by the light intensity applied to donor plants, but not by slight (circa 6 • C) temperature changes [35]. Interestingly, the viability of eggplant microspores was not dependent on light intensity at the moment of excision of the floral buds, but it was influenced by the amount of light that donor plants were exposed to during the two days prior to excision [35].…”

“…Interestingly, the viability of eggplant microspores was not dependent on light intensity at the moment of excision of the floral buds, but it was influenced by the amount of light that donor plants were exposed to during the two days prior to excision [35]. Moreover, although microelements such as boron has been shown to increase pollen quality in pepper [43], the foliar application of boron at low doses produced no effects in the viability of eggplant microspores, and notably reduced it at high doses [35]. Despite the economic importance of eggplant, modifications of the different parts of this protocol to make it more efficient were not proposed until more than fifteen years later.…”

“…A microspore density between 1 × 10 5 and 5 × 10 5 microspores/mL was initially proposed [19]. Recently, a more detailed assay was performed to narrow down this range of cell densities [35]. The highest number of microspore-derived calli was produced when microspores were cultured at densities between 2 × 10 5 and 3 × 10 5 .…”

“…Establishment of a protocol for anther culture in liquid medium. m 2020 [35] Effect of light intensity over donor plants and in vitro microspore density in the embryogenic response.…”