|NURUL, ISLAM-FARIDI - West Texas A & M University|
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2014
Publication Date: 8/1/2014
Citation: Sakhanokho, H.F., Nurul, I. 2014. Spontaneous autotetraploidy and its impact on morphological traits and pollen viability in Solanum aethiopicum. HortScience. 49(8):997–1002.
Interpretive Summary: Solanum aethiopicum is also known as scarlet eggplant, Ethiopian eggplant, “pumpkin on a stick”, or “mock tomato”. The plant is native to African but can now be found in many parts of the world. The fruits, leaves, shoots, and roots of scarlet eggplant are used for both food and medicinal purposes, with the specific uses depending on the geography and plant type. Some scarlet eggplants are used as ornamentals. Scarlet eggplant belongs to the same family as tomato and the common eggplant with which it can hybridize. In addition, it has shown tolerance to some pathogens that affect tomato and the common eggplant. Doubling the chromosome number of a plant is done for various purposes including removing hybridization barriers due to differences in chromosome numbers and improving a desired trait. Therefore, the purpose of this study was to assess the impact of chromosome doubling on pollen viability as determined by in vitro germination and on selected morphological traits including plant height, leaf size, fruit numbers, fruit dimensions, and weight. For fruit production, no significant differences were found between tetraploid (in this case, plants whose chromosomes were doubled) scarlet eggplants and the diploid (control) plants. Compared with the diploids, the tetraploid plants were significantly shorter and had wider leaves, and smaller fruits. Therefore, tetraploid scarlet eggplants can be valuable for future breeding programs, in particular for those programs aiming to develop shorter, more compact plants. Moreover, some scarlet eggplants are cultivated for their edible leaves, so tetraploid plants producing large leaves would be desirable.
Technical Abstract: We report for the first time the incidence of spontaneous autotetraploidy in Solanum aethiopicum (PI 636107). Stomatal dimensions and frequency, chloroplast numbers per guard cell, flow cytometry, and chromosome counts were used to differentiate the diploid plants from tetraploids. The impact of increased ploidy on pollen viability as assessed by in vitro germination and on selected morphological traits was evaluated. In vitro pollen germination was reduced in tetraploid plants, but no significant differences were found in fruit production per plant between diploid and tetraploid plants. Compared with the diploids, the tetraploid plants were significantly shorter and had wider leaves, and smaller fruits. Therefore, tetraploid S. aethiopicum plants can be valuable for future breeding programs, in particular for those programs aiming to develop shorter, more compact plants. Moreover, some S. aethiopicum plants are cultivated for their edible leaves, so tetraploid plants producing large leaves would be desirable. Additionally, the availability of tetraploid S. aethiopicum could remove hybridization barriers caused by ploidy differences with other tetraploid Solanum species.