Effect of Different Oryzalin and Colchicine Applications in Liquid Medium on Tetraploid Plant Production in Eggplant

Journal of Applied Biological Sciences Uygulamalı Biyoloji Bilimleri Dergisi E-ISSN: 2146-0108, 11 (3): 42-47, 2017, www.nobel.gen.tr Effect of Different Oryzalin and Colchicine Applications in Liquid Medium on Tetraploid Plant Production in Eggplant İlknur KÜLAHLIOĞLU1* Sebahattin ÇÜRÜK1 1 Faculty of Agriculture, Department of Horticulture, Mustafa Kemal University, Hatay, TURKEY *Corresponding Author E-mail: Received: October 23, 2017 Accepted: December 27, 2017 Abstract The objective of this study is to investigate the effects of different concentrations of oryzalin and colchicine that were applied in the in vitro liquid medium on the tetraploid plant production in eggplant cultivars, Karnaz F1 and Faselis F1. In the study, 2.5 or 3.75 mM of colchicine for 8, 16 or 32 hours; and 28.8 or 43.2 µM of oryzalin for 12, 24 or 36 hours were applied to the shoot tips and stem buds in the regeneration medium that composed of liquid MS medium supplemented with 0.5 mg/l BA and 10 g/l sucrose. The explants were shaken at 100 rpm under light intensity of 20-30 μmol/m2s over a 12/12 h (light/dark) photoperiod, and were placed on the regeneration medium without colchicine and oryzalin. Ploidy levels of the regenerated plantlets were determined by flow cytometry. The experimental design consisted of a completely randomized factorial design with three replicates per treatment. In the Karnaz F1 and Faselis F1 cultivars, tetraploid plants could not be obtained from colchicine applications. However, tetraploid plant was produced from the application of 28.8 μM oryzalin for 24 hours in Faselis F1, though the plant died during acclimatization. In Karnaz F1, the highest number of tetraploid plants were obtained from the treatment of 43.2 μM oryzalin for 12 hours or of 28.8 μM oryzalin for 36 hours. The pollen viability and germination percentages of these plants were 76.80% and 22.50%, respectively. Keywords: Polyploid plant, Antimitotic agent, In vitro application, Pollen fertility INTRODUCTION Eggplant (Solanum melongena L.) is an economically important vegetable crop grown in various tropical and temperate parts of the World (Asia and Africa) [1, 2]. The ethno-botanical history of eggplant is quite fascinating given its uses as food crop, medicine, and ornamental by Ancient (Indian) and Medieval (Arabic and European) civilization, and diverse beliefs surrounding its use including aphrodisi- acal properties and various effects [3]. The leading eggplant producer countries in the World are China (27.79 million tons), India (12.41 million tons), Egypt (1.21 million tons), Turkey (824 thousand tons) and Iran (763 thousand tons) between 2010-2014 [4]. However, eggplant is susceptible to numerous diseases and parasites, particularly bacterial wilt, Fusarium and Verticillium wilts, nematodes and insects [5, 6]. It is reported that soil-born pathogens such as Fusarium, Verticillium and Meloidogyne spp. may cause significant yield loss in eggplant; and in the soils contaminated with R. Solanacearum this loss can be in the range of 50-100% [7, 8]. S. torvum has been identified to carry traits of resistance to the most important diseases such as Fusarium oxysporum, Verticillium, root-knot nematode and bacterial wilts of eggplant [9, 8, 10]. Different studies have been carried out by using crossing and somatic hybridization methods in order to transfer these desirable traits from S. torvum to S. melongena. To our knowledge, however, since the interspecific hybrids produced from hybridization of these two species are generally infertile, satisfactory results have not been obtained from the studies carried out so far [11, 12, 13]. Various approaches can be applied to overcome this hybridization barrier. For example, tetraploid plants can be obtained by applying antimitotic agents to S. torvum and S. melongena. It may be possible to produce fertile interspecific plants when these fertile tetraploid plants are hybridized. As a second approach, by chromosomal doubling of S. melongena cultivars and of infertile diploid interspecific genotypes obtained from crossing of S. melongena and S. torvum, it may be possible to achieve fertile polyploid plants that can be crossed to produce interspecific tetraploid progenies. As a result of different studies, it has been reported that sexual compatibility was provided when the tetraploid potato that have been produced by chromosome doubling of wild diploid potato genotypes, crossed with cultivated tetraploid potatoes belonging to Solanum [14]. Ramanna and Hermsen 1981 [15] have produced fertile tetraploid plants by chromosomal doubling of sterile interspecific hybrid genotypes which were obtained by hybridization of tuberous diploid S. pinnatisectum and non-tuberous diploid S. etuberosum. Afterwards, fertile hexaploid genotypes were improved by hybridization of pollens of these tetraploid plants and tetraploid S. acaule [16]. Plants with doubled chromosome set were achieved by applying 0.05% colchicine to shoot tips of the hybrids between S. melongena and S. macrocarpon [17] or S. melongena and S. integrifolium [18], under in vitro conditions. While pollen viability rates increased up to 70% in the amphidiploid plants obtained from the genotypes of S. melongena x S. integrifolium, the ratio increased up to 40% from 0.86% when chromosome were doubled in plants which were occurred as a result of hybridization of S. melongena and S. macrocarpon. İ. Külahlıoğlu et al. / JABS, 11 (3): 42-47, 2017, www.nobel.gen.tr In order to apply both of these approaches, first of all, it is necessary to produce tetraploid plants of S. melongena cultivars. Different mitotic agents such as colchicine, oryzalin, trifluralin or amiprofos-methyl were used for polyploidization [19]. Initially, antimitotic agents were used in vivo, but recently in vitro applications have become prominent. Praça et al. [20] reported that they obtained tetraploid plants by 11.11% when they applied 8 mM colchicine to the shoot tips of tomato (Solanum lycopersicum L.) for 96 hours in liquid medium. The tomatillo (Physalis ixocarpa Brot.) seeds were germinated on the colchicine concentrations ranged between 0.04 and 0.20% for 24 hours, and best results (67% and 65%) were achieved from the application of 0.12 and 0.16% colchicine [21]. The tetraploid plants produced by using antimitotic agents in S. melongena cultivar can also be used for cultivation and in breeding program. Because, the polyploid plants have superior morphological changes, genetic adaptation and tolerance to environmental stresses, compared to diploids [22, 23, 24]. Osborn et al. [25] declared that polyploidy plants had a high level of gene expression compared to diploids. On the other hand, polyploid plants can exhibit several physical properties (drought stress or disease resistance) and cultivation characteristics (flowering, post-harvest quality, etc.) that are important for commercial success in horticulture and agriculture crops (...truncated)