Tadahisa Higashide

CMV resistance developed in vigorous-growing lateral shoots from virus infected plants of Capsicum annuum L.

Abstract Vigorous-growing lateral shoots were observed emerging from certain pepper cultivars infected with cucumber mosaic virus (CMV) about 2 years after infection. They exhibited no CMV symptoms. When checked by enzyme-linked immunosorbent assay (ELISA), CMV was not detected in the vigorous-growing lateral shoots which emerged from Capsicum annuum L. ‘Af-5’ plants infected with CMV, in spite of a high concentration of CMV in the infected shoots. Vigorous-growing cuttings from ‘Af-5’ plants did not express CMV symptoms, regardless of either the renewal frequency by cutting propagation or the duration of growing. In these cuttings, CMV was never detected when checked by either ELISA or the grafting method. Vigorous-growing cuttings inoculated with CMV by aphids showed no symptoms of CMV, with a CMV concentration index of 0. When tested by the grafting inoculation method, ‘Af-5’ vigorous-growing cuttings were resistant to CMV.

Differences in vernalisation responses in onion cultivars

ABSTRACT Onions normally form bulbs in the first year of growth; however, exposure to low temperatures can induce flowering (vernalisation) before bulbs are produced. Based on the cultivation data of onions grown in Japan, we evaluated and validated a reported model describing the onion vernalisation response. The observed bolting rates of ‘Sapporoki’, which was used in the construction of a previous model, were a good fit to the model, whereas, the bolting rates of one of the overwinter-type cultivars, ‘Momiji No.3ʹ, were lower than the predicted value. The difference between the predicted and observed bolting rates in ‘Momiji No.3ʹ was caused by a larger VD0.5, the coefficient in vernalisation response models that represents the time point when half of the plants have bolted. Overwinter-type and/or bolting resistant cultivars can have parameters that indicate a further vernalisation requirement for bolting. The parameters in our model can be customised to the cultivar being investigated, and our study suggests the viability of modelling onion bolting by using air temperature.