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Beyl, C.A. 1990. Fire blight susceptibility in a young Asian pear planting. p. 376. In: J. Janick and J.E. Simon (eds.), Advances in new crops. Timber Press, Portland, OR.

Fire Blight Susceptibility in a Young Asian Pear Planting

Caula A. Beyl

Fire blight (Erwinia amylovora), a bacterial disease native to North America, is one of the limiting factors for successful commercial production of pears in the eastern U.S. Increased interest in Asian Pear has generated questions of its fire blight susceptibility. To evaluate this, a trial of 18 cultivars on 4 different rootstock including Pyrus communes 'Winter Nelis', P. ussuriensis, P. calleryana, and P. betulaefolia was established in 1984 on the campus at Alabama A&M University, Normal, AL. Scion cultivars included 'Chojuro', 'Doitsu', 'Erishinge', 'Hosui', 'Ishiwase', 'Kikusui', 'Kumoi', 'Megeitsu', 'Niitaka', 'Okusankichi', 'Seigyoku', 'Seuri', 'Shinko', 'Shinseiki', '20th Century', 'Ya Li', 'Shin Li', and 'Daisu Li'. In 1986, the best ten cultivars with least susceptibility to fire blight were 'Doitsu', 'Seuri', 'Hosui', 'Shin Li', 'Megeitsu', 'Ya Li', 'Shinko', 'Erishinge', 'Kikusui', and 'Daisu Li'. In 1988, with the majority of trees bearing and no longer juvenile, the three best cultivars were Shinko', 'Ya Li', and 'Shin Li' closely followed by 'Seuri', 'Megeitsu', and 'Doitsu'. Highest fire blight susceptibility in 1988 was found in 'Okusankichi', '20th Century' and 'Seigyoku'. With respect to the rootstock those cultivars on Pyrus betulaefolia had a lower USDA fire blight rating with a larger percentage of tree surface blighted than did the other three species of rootstock. By 1988, there was little difference with regard to the percentage of trees flowering as a function of rootstock.


Vega de Rojas, R. and S. Kitto. 1990. Regeneration of Carica pentagona (Babaco). p. 376. In: J. Janick and J.E. Simon (eds.), Advances in new crops. Timber Press, Portland, OR.

Regeneration of Carica pentagona (Babaco)

Rebeca Vega de Rojas and Sherry Kitto

Babaco (Carica pentagons) is a subtropical tree naive to Ecuador that produces seedless fruits having a sweet-tart taste. Recent worldwide availability of babaco is due to mass propagation in vitro. Because there are only female plants, babaco can not be improved using conventional breeding techniques. Improvement of babaco may be possible by using issue culture regeneration/selection techniques. Babaco ovules at various developmental stages (10 to 150 days old) and peduncle nodal sections (1 cm) were cultured in order to produce regenerative cultures. Media components consisted of Murashige and Skoog salts and vitamins supplemented with glutamine (400 mg/l), sucrose (3-6%, w/v) and washed Difco Bacto agar (0.8%, w/v). Growth regulators for ovules included BA (0-3 mg/l) and NAA (0-2 mg/l) and for peduncles included BA (0.5 mg/l) and IAA (2 mg/l). The pH was adjusted to 5.7-5.8 before autoclaving. Cultures were grown at 23+/-2°C under cool-white fluorescent lamps (18 hr photoperiod, 60 µ mol m-2 s-1). Ovular callus initiation and growth was obtained in the dark when ovules were pretreated by chilling (4°C). Callus cultures transferred every 5 to 6 weeks for a year have maintained a consistent growth rate. Calluses grown in the light have developed green areas that have subsequently produced nodular structures. The nodular structures have initiated shoot primordia that develop into shoots when growth regulators are removed. Histological studies have identified two types of calluses that originate either from the nucellus or the integuments. The nucellar callus appears to have more differentiative potential than the integument callus. Also, babaco ovules appear to be normal, vascularized and complete structures. Axillary shoots have been proliferated from peduncle nodal sections.

Vega de Rojas, R. and S. Kitto. 1990. Regeneration of Carica pentagona (Babaco). p. 376. In: J. Janick and J.E. Simon (eds.), Advances in new crops. Timber Press, Portland, OR.

Regeneration of Carica pentagona (Babaco)

Rebeca Vega de Rojas and Sherry Kitto

Babaco (Carica pentagons) is a subtropical tree naive to Ecuador that produces seedless fruits having a sweet-tart taste. Recent worldwide availability of babaco is due to mass propagation in vitro. Because there are only female plants, babaco can not be improved using conventional breeding techniques. Improvement of babaco may be possible by using issue culture regeneration/selection techniques. Babaco ovules at various developmental stages (10 to 150 days old) and peduncle nodal sections (1 cm) were cultured in order to produce regenerative cultures. Media components consisted of Murashige and Skoog salts and vitamins supplemented with glutamine (400 mg/l), sucrose (3-6%, w/v) and washed Difco Bacto agar (0.8%, w/v). Growth regulators for ovules included BA (0-3 mg/l) and NAA (0-2 mg/l) and for peduncles included BA (0.5 mg/l) and IAA (2 mg/l). The pH was adjusted to 5.7-5.8 before autoclaving. Cultures were grown at 23±2°C under cool-white fluorescent lamps (18 hr photoperiod, 60 µ mol m-2 s-1). Ovular callus initiation and growth was obtained in the dark when ovules were pretreated by chilling (4°C). Callus cultures transferred every 5 to 6 weeks for a year have maintained a consistent growth rate. Calluses grown in the light have developed green areas that have subsequently produced nodular structures. The nodular structures have initiated shoot primordia that develop into shoots when growth regulators are removed. Histological studies have identified two types of calluses that originate either from the nucellus or the integuments. The nucellar callus appears to have more differentiative potential than the integument callus. Also, babaco ovules appear to be normal, vascularized and complete structures. Axillary shoots have been proliferated from peduncle nodal sections.
Last update March 13, 1997 by aw