Seed Priming Influence on Germination and Emergence of Pepper Seed Lots

Seed priming can markedly increase the germination rate of pepper (Capsicum annuum L) seed, but has not always been accompanied by improvements in field emergence rates or percentages. Furthermore, optimal priming conditions may vary among cultivars and even seed lots of a given species. The objective of this study was to evaluate the influence of a standard seed priming procedure on the laboratory germination and field emergence of a large number of pepper seed lots. Forty-two (1986 study) or 30 (1987 study) lots of ‘Yolo Wonder’ and ‘Anaheim’ pepper (all >80% viability) were primed for 7 d at 25 °C on blotters saturated with 30 g KNO₃ kg⁻¹ H₂O solution, rinsed, and dried. Control (untreated) and primed seeds were then germinated in the laboratory at 20 °C or planted in field emergence trials at two locations (Davis and Fresno, CA) in yr. Priming slightly reduced final laboratory germination percentages, but also decreased the mean times to germination (MTG) 71 to 78%. Field emergence percentages generally were unaffected by priming, but mean times to emergence (MTE) were reduced 8 to 29%. There was a strong interaction between seed lots and priming response, with the slowly germinating lots exhibiting the greatest benefit from priming. In both the laboratory and field, the reduction in time to germination or emergence due to priming was linearly related to the initial MTG or MTE. A quadratic relationship between the MTG and MTE of control seeds extrapolated through the same data for primed seeds. Thus, while laboratory germination percentages were a relatively poor predictor of field emergence percentages for these relatively high-quality seed lots, laboratory MTG was highly correlated with field MTE in two of three field trials. Although seed lots differed in the magnitude of their response to a standard priming treatment, all lots exhibited markedly improved rates of germination and emergence after priming. This paper was supported in part by Western Regional Research Project W-168 (Seed Production and Quality Investigations) and a grant from the California Pepper Improvement Foundation.