Inheritance, Heritability and Heterosis in the Scarlet Eggplant

Start date: 21 November, 2010 End date: 2 June, 2011 Project type: Master's Thesis (prior to 2018) Project code: A10278 Countries: Tanzania Institutions: University of Copenhagen (UCPH), Denmark Grant recipient: Sabrina Meier Total grant: 10,000 DKK



The Scarlet eggplant (Solanum aethiopicum L.) is an important vegetable crop all across sub-Saharan Africa. It belongs to the same Solanaceae subgenus as the more popular brinjal eggplant or aubergine (Solanum melongena L.). So far little breeding efforts have been undertaken to improve S. aethiopicum. Thus, the aim of this study is to investigate the inheritance, heritability and heterosis of some economically important traits in S. aethiopicum. Three field trials were designed including various parental entries and their hybrid test crosses as well as three different F2 and two backcross populations in order to meet this goal. Some important pests and diseases were also assessed according to their appearance in the field during the experimental period.

Broad-sense heritability estimates were calculated from the results of the F2 and backcross populations. The flowering and fruiting date have high heritabilities of 88 % respectively 75 %. The cluster morphology and fruit set have reasonable heritabilities (70 % and 56 %) whereas early plant height is greatly influenced by the environment. Narrow-sense heritability was estimated through offspring-parent regression of F1 and mid-parent values and was high for mature plant height (82 %), the number of fruit per plant (93 %) and fruit yield (81 %). The hybrids showed significant high parent heterosis for the number of flowers and fruit per cluster as well as the total number of fruit per plant and early plant height. Earliness and fruit yield was significantly increased over the calculated mid-parent values. Fruit weight seems to be reduced due to the increased number of fruits per plant and the hybrids show negative mid-parent heterosis for this trait. 

Further, the inheritance of some plant and fruit morphological traits was observed, the fruit taste (bitterness) investigated through two different testing methods. The effects of ten yield components on total fruit yield was assessed. A number of resistance mechanisms against red spider mites (Tetranynchus spp.) are identified and discussed. S. aethiopicum hybrids have a great potential in crop production. Successful inbred parents should be selected for earliness, number of fruits and fruit weight along with further desirable fruit traits.