APS_October 2018

R aspberry

255

4.5

Prelude Killarney Canby Moutere Titan Encore K81-6

4.0

3.5

3.0

2.5

2.0

1.5

Mean Fruit Weight (g)

1.0

0.5

0.0

170

175

180

185

190

195

200

205

210

215

Julian Date

354 355 Figure 1: Mean fruit weight over three seasons for 7 floricane raspberry cultivars through the 356 harvest season. (Julian date 170 corresponds to June 19 and 215 to August 3). Figure 1. Mean fruit weight over three seasons for 7 floricane raspberry cultivars through the harvest season. (Julian date 170 corresponds to June19 and 215 to August 3).

357 358 359

‘Prelude’ being generally small in size (Table 2). Fruit weights also tended to decline as the seasons progressed (Figure 1) with the heaviest fruit harvested in the beginning of the season. However, in the latest cultivars, the fruit at the end of the season increased in size when few fruit were present (Figure 1). ‘Encore’ was the most uniform in weight over the harvest periods with ‘Canby’ and ‘Killarney’ also being relatively uniform al- beit smaller (Fig. 1).  The fruit in this trial often started relative- ly small and increased in mean weight until peak harvest at which point there was a drop- off in fruit weight. This was followed by an- other increase in size, often with maximum fruit size recorded after the peak harvest date when the crop load was low followed by a steep drop-off at the very end of the season. This pattern differed in the primocane rasp- berry where the largest fruit was observed at the beginning of the season with a decline in mean size as the season progressed (Yao and Rosen, 2011), sometimes with a spike after

peak harvest which would then diminish as the season concluded (Weber, 2018). The fruit weights among plots was much more variable in floricane cultivars than that ob- served in primocane fruiting cultivars. It may be more highly influenced by the relatively higher July temperatures and varying water status of the plants as irrigation was needed more frequently to maintain adequate soil moisture.  Variation in mean fruit size during the sea- son was greatest for ‘Moutere’ with mean reduction from maximum to minimum mean fruit weights of 44% over the 3 year period. ‘Prelude’ produced the most consistent fruit weights over the three seasons, averaging only a 21% decrease from the maximum to minimum mean weight. The other cultivars varied between 34% and 40% reduction in fruit weight between the maximum and mini- mum (data not shown). This wide difference in fruit weight uniformity among the culti- vars suggests a strong genetic effect on this character. Therefore, improving this unifor-