inter-specific cross. It wa^; hoped that a large-fruit, red eggplant might also 

 be obtained. The first-generation hybrid plants proved unfruitful both in 

 the greenhouse and open field. Self-pollinated flowers on plants in the 

 greenhouse failed to set fruits. Nevertheless, backcrosses to both parents 

 were successfully made in the greenhouse though many of the red-ripe fruits 

 were parthenocarpic. Fruits devoid of seeds also occurred in the field. In 

 the greenhouse, only six plump seeds were obtained from twelve fruits re- 

 sulting from a backcross to New Hampshire. Ordinarily a single eggplant 

 fruit will have hundreds of seeds. When the first-generation hybrid was 

 backcrossed to the Chinese Red eggplant, a total of 65 seeds was realized 

 from many fruits saved in the greenhouse. 



Some first-generation plants (New Hampshire x Chinese Red) and 

 (Morden x Chinese Red I were treated with colchicine by Mr. Stanley Berry* 

 to see if lines of tetraploid plants might be more fertile than the self- 

 unfruitful diploids. Two fruits, two and one half by two inches in di- 

 ameter and much larger than any parthenocarpic fruits, occurred on a 

 branch of an F^ -plant of Morden x Chinese Red. a plant that had been 

 treated with colchicine. These two fruits gave 110 rather large seeds. 



Plants for the next generation, both of the backcrosses and the colchicine- 

 treated lot, proved interesting when grown in the field. However, the 

 latter proved so late in maturity and relatively infertile that only one line 

 has been maintained — and with difficulty — up to the present time. 

 It has red, oval fruits borne in clusters and up to 3 inches in diameter. 



Some fruitful plants occurred in the first backcross generation and five 

 early selections were made for use in continued breeding. This has taken 

 the approach of further backcrosses and mating of selected plants. 



It became apparent that open-pollinated plants in the field had been 

 out-crossed rather frequently instead of self-pollinated. So a regular pro- 

 cedure was used of making single-plant selections in the field in the fall 

 to be taken into the greenhouse during the winter for self-pollination. 

 An unexpected result has been the appearance of many spiny plants in 

 subsequent generations though both parents of the cross are unarmed. 

 This has caused the discarding of many plants. 



Breeding work has proceeded now through three backcrosses with con- 

 tinued selection of selfed plants. Several lines of early, large, dark-fruited 

 eggplant that set somewhat in clusters are at hand, and also some of a 

 large green-fruited line that have mature yellow fruits instead of the 

 desired red color. 



This has proved to be a 'difficult breeding project because of self-sterility 

 of the interspecific cross, and failure of many plants in following gener- 

 ations to mature even one fruit. 



Ground Cherry Breeding 



The ground cherry, also called husk tomato and termed Cape Gooseberry 

 in England and South Africa, is an important commercial crop used for 

 preserves or jam in those countries. The species of ground cherry of im- 

 portance in the old world countries is Phy sails peruviana. In the United 

 States, two other species are used for garden crops to a rather limited ex- 

 tent. The common ground cherry. P. barbadensis, produces yellow berries 



Graduate Assistant in Horticulture. 1952-53. 



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