Abstract

The objective of this study was to develop information useful to pepper (Capsicum annuum L.) rootstock breeders, grafted plant propagators and growers managing commercial plantings in semi-protected settings. To accomplish this, an experiment involving four phenotypically diverse scion cultivars and five rootstocks grafted in all combinations along with self-grafted and non-grafted cultivars as controls was completed twice. The effects of the grafting process, scion cultivars and rootstock genotypes on grafted plant performance were delineated by measures of post-grafting plant survival (%), plant vegetative vigor and by early and total season yield parameters. The grafting process significantly increased vegetative vigor parameters, most notably in 2014 whereas the yield parameters of self-grafted plants exceeded their non-grafted counterparts only in 2015. In both years, scion performance in graft combinations remained characteristic of the cultivar type; long-fruited cultivars ‘Eigman’ and ‘Kurtovszka Kapia’ had lower survival rates, generally exhibited greater vegetative vigor, and amassed greater yields per m2 than blocky-fruited ‘Toronto’ and ‘Zedinca’. In general, graft combinations using commercial pepper rootstocks 52-03 RZ and Tan Tan (No: 12G076) outperformed those composed of standard cultivars or breeding lines used as rootstocks. Scions on these rootstocks exhibited greater vegetative vigor in both years and higher yields per m2 than non-grafted controls in 2014. The superior performance of 52-03 RZ and Tan Tan (No: 12G076) in this study exemplified the advantage of using rootstocks specifically bred for optimum root system performance and compatibility with a variety of scions. However, significant scion × rootstock interactions and seasonal differences in performance suggested, that as new rootstocks are developed or as new graft combinations are introduced, it will be necessary to rigorously test them in multiple environments to insure commercial success.

Keywords: Capsicum; Grafting; Rootstock development; Grafting effects; Rootstock effects; Scion effects; Survival; Vegetative growth; Fruit yield