|Authors: ||G.L. Reighard, D.R. Ouellette, K.H. Brock|
|Keywords: ||Pyrus pyrifolia, Pyrus bretschneideri, fire blight, fruit|
Seven Asian pear cultivars ('Atago', 'Hosui', 'Niitaka', 'Olympic', 'Shinko', 'Shin Li' and 'Ya Li') on Pyrus betulaefolia rootstock were planted in 1996 near Clemson, South Carolina.
Trees were trained to a central leader system.
Data recorded through 2006 included trunk circumference, tree survival, fire blight incidence, full bloom date, fruit maturity date, fruit size, and fruit yield. 'Hosui', 'Ya Li' and 'Shin Li' were the most vigorous cultivars. 'Shinko' was the least vigorous.
Mean full bloom dates among cultivars varied by 11 days. 'Ya Li' consistently bloomed earliest, whereas 'Olympic' and 'Shinko' bloomed latest.
Fruit maturity dates were distinct among cultivars.
Ripening times progressed from first 'Hosui' followed by 'Niitaka', 'Atago', 'Shinko', 'Olympic' and then last with 'Shin Li' and 'Ya Li', which both ripened ˜39 days after 'Hosui'. Cumulative fruit yields per tree among cultivars were significantly different only between 'Shin Li' (673 kg) and both 'Hosui' (460 kg) and 'Ya Li' (449 kg). However, these same cultivars also differed significantly in fruit size. 'Shin Li' had the largest mean fruit weight (408 g); whereas 'Hosui' (250 g), 'Shinko' (224 g) and 'Ya Li' (206 g) the smallest.
The other cultivars were statistically similar with mean fruit weights from 352 to 389 g.
Cumulative yield efficiency (kg/cm2) was significantly different among cultivars with 'Atago' (4.16) being more than twice as yield efficient as 'Hosui' (1.87). 'Shinko' (3.48) was also yield efficient, whereas 'Ya Li' (2.29) was not.
Some alternate bearing occurred and was most pronounced in 'Ya Li'. In addition, 'Ya Li' was less precocious in fruiting than the other cultivars and was more prone to yield losses due to frosts.
Fire blight strikes occurred in most trees during the trial, but 'Shinko' had few fire blight strikes, while the majority of 'Ya Li' trees were infected and eventually killed despite a spray program.
Download Adobe Acrobat Reader (free software to read PDF files)