Seed production and longevity, seasonal emergence and phenology of wild radish (Raphanus raphanistrum L.)

Abstract

Experiments conducted from 1977 to 1979, at Rutherglen, north-eastern Victoria, investigated seed production, seed longevity, seasonal emergence and phenological development in wild radish (Raphanus raphanistrum L.), a weed of field crops. Seed production of wild radish reached 17 275 seeds/m2; seeds retained viability and germinated over a period of three years. The loss of viability was faster at the soil surface or at 1 cm depth than at 5 or 10 cm. Of 1000 wild radish seeds buried at 1 cm depth, 737 emerged after three years, compared with 367, 167 and 5 at 0.5 and 10 cm, respectively. Phenological development of wild radish was affected by time of planting, and the duration of the period from plant emergence to plant senescence ranged from 5 to 10 months. Temperature appeared to influence development up to flowering, but photoperiod affected the length of flowering. Plants emerging at any time during the year were able to flower and seed successfully. The implications of these findings for control programs are discussed.

The biology of Canadian weeds. 132. Raphanus raphanistrum L.

“…In an Australian weed survey in winter crops, R. raphanistrum was one of the three most widespread and abundant weeds, and the one whose spread was the most difficult to control, particularly in the southern and western regions where herbicide resistance has developed (See Section 11) (Alemseged et al 2001). Densities as low as 10 wild radish plants m -2 reduced wheat yields by up to 20% (Reeves et al 1981), with up to 50% reduction at densities of 80 wild radish plants m -2 (Hashem et al 2001a). The initial flush of germination followed by sporadic germination throughout a long growing season contributes to herbicide control problems in Australia (Donaldson 1986).…”

“…A positive correlation was found between total seed production and the number of days from sowing to first flowering (Cheam 1986). In a 3-yr study (Reeves et al 1981), R. raphanistrum seed production in winter wheat ranged from about 150 to over 1000 seeds per plant at densities below 10 plants m -2 and decreased to 67 seeds per plant at 247 plants m -2 . Although results varied between years and with wild radish density, seed production was estimated as high as 17 275 seeds m -2 .…”

“…Crop planting time can have a marked effect on phenological development of R. raphanistrum (Reeves et al 1981). In Australia, wild radish can germinate all year.…”

“…In crops and regions where control measures are less effective, as in canola crops in Australia, R. raphanistrum populations have continued to spread (see Section 3a). In warm zones, where there are fewer seasonal limitations, this species has been an even more aggressive colonizer of agricultural land (Reeves et al 1981;Murphy et al 1998a;Anonymous 2003).…”

“…A 3-yr Australian field study (Reeves et al 1981) that compared seeds buried at various depths (0 to 10 cm) found that viability declined over succeeding years, with the greatest decline among seeds on the soil surface. For seeds buried at 5-10 cm, the decline was slower, with 43% remaining viable 4 yr after burial at 10 cm.…”