plant architecture to explain the architectural variability observed and to combine correlated variables into one ( Crespel et al., 2013 ). They were plant height (measured in centimeters), the number of primary shoots (initial complete shoots that
Xuan Wu, Shuyin Liang and David H. Byrne
Ben van Hooijdonk, David Woolley, Ian Warrington and Stuart Tustin
et al., 2001 ; van Hooijdonk et al., 2010 ) of the primary shoot. In addition, fewer axillary buds on the primary shoot tended to grow out; thus, fewer secondary shoots formed ( Jaumien et al., 1993 ; van Hooijdonk et al., 2010 ). In contrast
Takahiro Tezuka, Masashi Harada, Masahumi Johkan, Satoshi Yamasaki, Hideyuki Tanaka and Masayuki Oda
). This method enables in vivo adventitious shoot regeneration from stumps after decapitation of the primary shoot and all lateral branches. Harada et al. (2005) reported that 79 shoots were regenerated from the cut surface of primary shoots and lateral
Hiroaki Ito, Masaki Ochiai, Hiroaki Kato, Katsuhiro Shiratake, Daigo Takemoto, Shungo Otagaki and Shogo Matsumoto
started re-growing after 1 month, and newly generated leaves also showed a photo-bleached phenotype (data not shown). The fourth seedling exhibited the most severe phenotype ( Fig. 4 ). Although the primary shoot showed no photo-bleached phenotype, the
Grace Q. Chen
transferring the calli to CSI+ medium, most of the calli generated one primary shoot and a few generated zero or two primary shoots. So the overall primary shoot generation to leaf segments ratio was between 22.5% and 60%. Table 1. Number of calli and shoots
William Garrett Owen
indices (GI), primary shoot caliper (PSC), and total plant dry mass (TDM) of two hibiscus ( Hibiscus hybrid L. ‘Mocha Moon’ and ‘Starry Starry Night’) cultivars grown at six fertilizer concentrations, harvested at 8 weeks after transplant. Fig. 1
J.G. Williamson, D.C. Coston and J.A. Cornell
Planting treatments were evaluated for their influence on shoot development and root distribution of own-rooted `Redhaven' peach [Prunus persica (L.) Batsch] trees planted to high density (5000 trees/ha). Planting in fabric-lined trenches (FLT) or narrow herbicide strips (NHS) reduced the diameter and length of primary shoots, the number and combined length of second-order shoots, and the total length of shoots. Flower density, the number of flowers per node, and the percentage of nodes containing one or more flowers were increased for FLT trees but not for NHS trees when compared with controls. The length of primary shoots increased quadratically for all treatments with increasing limb cross-sectional area (LCA). The total length of shoots increased more with increasing LCA for controls than for FLT trees. The number of flowers per shoot increased linearly for all treatments with increasing LCA values. Root concentration decreased with increasing soil depth and distance from tree rows for all treatments. Reduced widths of weed-free herbicide strips had little effect on root distribution. Roots of FLT trees were reduced in number and restricted vertically and laterally when compared with other planting treatments. The FLT treatment modified shoot development by reducing the length of total shoots and length of primary shoots across LCA values measured when compared with NHS and control-treatments.
Saïda Sghir, Philippe Chatelet, Noureddine Ouazzani, Françoise Dosba and Ilham Belkoura
The responses of several Moroccan and French olive (Olea europaea L.) cultivars to various strategies for in vitro establishment and culture were compared. A cultivar effect was clearly observed with `Haouzia' cultivar being more readily multiplied. ZR produced the best response in all the cultivars studied, in particular when considering the time elapsed between explant inoculation and budbreak for 50% of the explants (lag phase), growth of the primary shoot and the multiplication rate. Treatments with BA alone or combined with NAA increased the number of axillary buds and internodes without improving their growth. Root induction with IBA in the dark using a two-phase scheme resulted in the best rooting rate in shoots obtained in vitro, and this for all cultivars. Chemical names used: 6-benzyladenine (BA), indole-3-butyric acid (IBA), alpha-naphthalene acetic acid (NAA), zeatin riboside (ZR).
The grapevine shoot consists of nodes without clusters (inflorescences) basal to a zone in which leaf-opposed clusters are found at the nodes. Beyond the cluster zone leaf-opposed tendrils are borne at the nodes. The numbers and possible relationship of basal nodes and clusters are important in grapevine breeding and improvement. Basal node number influences cluster placement within the canopy, which relates to light penetration to the fruit and fruit maturation and to application of cultural practices, including harvest and cluster treatments. Cluster number is a primary yield component. Basal node and clusters numbers were counted on ten primary shoots each of forty grapevine (Vitis) accessions. The accessions analyzed are cultivars and wild species collections held in the United States National Plant Germplasm System. The correlation coefficient of the number of basal nodes and number of clusters was calculated using the means of the ten observations per accession. Basal node and clusters numbers were negatively correlated; the correlation coefficient was -0.763, which is significant (P <0.001). The negative correlation of basal node and cluster number has implications for grapevine improvement.
Thomas J. Zabadal and Thomas W. Dittmer
Varying amounts of vegetation-free area (VFA) were established around newly planted `Niagara' (Vitis labrusca L. × Vitis vinifera L.) grapevines to determine their influence on vine growth during the first growing season. VFAs were either circular with radii from 0 to 5 ft (0 to 152 cm) in one experiment or in bands from 0 to 8 ft (0 to 244 cm) in width in a second experiment. VFAs were maintained with biweekly manual weeding for the entire growing season. Leaf, shoot and root dry weights as well as the number of primary shoots and the length of the longest root were measured at the end of their first growing season. The thresholds for maximum vine dry weight biomass accumulation occurred with a circular VFA of 4 ft (122 cm). When banded VFAs were used, total vine dry weight biomass continued to increase up to the widest treatment of 8 ft (244 cm). Therefore, no threshold was attained. These are greater VFAs than typically established around vines in commercial plantings. Therefore, growers who desire to maximize vine growth of newly planted vines, should consider larger VFAs around vines than has been traditional unless such a practice is likely to cause surface soil erosion.