No abstract

We investigated the effect of the height of the primary scaffold branch on freezing injury, growth, yield, and fruit quality of the fig (Ficus carica L. 'Masui Dauphine'). The primary scaffold branch was adjusted to 1.8 m with a straight line and horizontal direction of the fruit-bearing shoots, compared with the conventional system of adjusting the primary scaffold branch to a height of 0.6 m with a straight line and vertical direction of the fruit-bearing shoots. The trees of the 1.8-m-high scaffold branch system showed less freezing injury (0% mortality) in spring over the successive two seasons, while those of the conventional 0.6-m-high primary scaffold branch system suffered 100% freezing injury. Fig growth and yield were undermined, but the fruit quality was much improved in the high (1.8 m) primary scaffold branch system relative to that of the conventional system, before freezing injury occurred. One of the reasons for the reduced freezing injury being associated with the new training system may be ascribed to the observation that the high primary scaffold branch can narrow the early morning and daytime temperature difference on the upper surface of the branch. The adoption of the 1.8-m-high scaffold branch is therefore expected to improve fig fruit quality and reduce freezing injury.

We aimed to determine the suitability of 'Reikodai 1 go' (BC 1 from interspecific hybridization of Ficus carica L. and F. erecta Thunb.) as a ceratocystis canker disease-resistant rootstock for 'Masui Dauphine' fig. In this study, 'Masui Dauphine' was grafted onto 'Reikodai 1 go' and grown in 45 L pots under artificial soil infestation with Ceratocystis ficicola Kajitani et Masuya. Ceratocystis canker resistance, tree growth, and fruit production was assessed by comparing scion growth and fruit production in 'Reikodai 1 go'-grafted and 'Masui Dauphine' own-rooted trees. No significant differences in the initial growth of the shoots (first year of planting) was observed between 'Reikodai 1 go'-grafted and own-rooted trees. 'Reikodai 1 go'-grafted trees demonstrated a tendency towards scion overgrowth. Soil inoculation with C. ficicola (nine times in three years; 2 L of suspension with 10 5 conidia/mL per pot) resulted in the death, or inhibited growth, of own-rooted trees. However, inoculated 'Reikodai 1 go'-grafted trees revealed no growth inhibition and had growth similar to those of non-inoculated own-rooted and non-inoculated 'Reikodai 1 go'-grafted trees. These results suggest that 'Reikodai 1 go'-grafted trees were highly resistant to soil infestation with C. ficicola. No significant differences were observed between 'Reikodai 1 go'-grafted trees with or without C. ficicola inoculation in terms of fruit production (considering fruit set, date of maturation, fruit length, width, fruit weight, estimated yield, skin color, and soluble solids content). When comparing fruit production of 'Reikodai 1 go'-grafted and own-rooted trees, no differences were observed between the two in terms of fruit characteristics. Therefore, the use of 'Reikodai 1 go' as a rootstock is unlikely to cause considerable problems in the fruit production of 'Masui Dauphine' fig trees. Overall, shoot growth and fruit production of 'Masui Dauphine' grafted onto 'Reikodai 1 go' were not significantly different from those of the own-rooted trees. Therefore, it is expected that the introduction of 'Reikodai 1 go' rootstock for 'Masui Dauphine' production will be an effective approach for controlling ceratocystis canker.

We investigated the shoot growth and fruit production of 'Masui Dauphine' fig trees (Ficus carica L.) with a newly devised "renewal long pruning" method and compared the results with those of conventional short pruning under straight-line training with both normal and high limb styles. This novel pruning method combines long pruning and continuous renewal pruning such that a few dormant shoots remain long and serve both as long mother shoots and as replaceable limbs. In experiments in 2009 and 2010, the shoots sprouted earlier from the renewal long pruning trees than from the short pruning trees. The number of lateral shoots was less in the renewal long pruning trees, indicating the prevention of excess vigour in bearing shoots. Renewal long pruning did not affect total percentage of fruit set; however, it slightly increased fruit set failure in the basal portion of bearing shoots. It potentially induced early maturation and greater enlargement of the fruit. Renewal long pruning was especially useful in high-limb straight-line training because it effectively compensated for disadvantage of this training, such as increasing numbers of lateral shoots and inhibition of fruit enlargement. Discipline:Horticulture Additional key words: high limb style, leaf-wood ratio, straight-line training.