Cultivars of bell pepper differ in susceptibility to bud/flower abscission. Reduction in the level of assimilate, and alterations in assimilate partitioning may be involved in the processes leading to bud/flower abscission. Four growth analysis experiments were conducted to determine whether two pepper cultivars differing in susceptibility to stress-induced abscission showed corresponding differences in growth and rates and dry matter partitioning when subjected to shade stress. The reduction in RGR and NAR with shading was significantly greater for the abscission-susceptible `Shamrock' than the more tolerant `Ace'. Partitioning of dry matter to reproductive structures was reduced by shading. There were no cultivar differences in the proportion of dry matter partitioned to young developing leaves. Fully expanded leaves comprised a larger proportion of total dry matter in `Shamrock'. The lower NAR of `Shamrock' under stress may have led to greater bud/flower abscission than `Ace' under shade stress. If preferential partitioning of dry matter to competing structures (developing leaves) is also involved, it was not detected using this technique.
Maren E. Veatch-Blohm, Dorothy Chen, and Matthew Hassett
saline irrigation (0, 25, or 50 m m NaCl) for 98 d preemergence and 35 d postemergence. Transpiration and g S values are reported for Day 133. As there were no cultivar differences the means within a salinity treatment are from all cultivars combined
Hiroshi Iwanami, Shigeki Moriya, Nobuhiro Kotoda, Sae Takahashi, and Kazuyuki Abe
shelf life conditions at 20 °C and proposed a regression parameter that could be used as an indicator of storage potential in breeding programs. Changes in fruit quality in shelf life conditions were rapid, and cultivar differences regarding the changes
Adolfo Rosati, Andrea Paoletti, Raeed Al Hariri, Alessio Morelli, and Franco Famiani
rootstocks ( Chandler and Heinicke, 1926 ; Forshey and Elfving, 1989 ; Mochizuki, 1962 ; Verheij, 1972 ). No studies, however, investigated whether cultivar differences in vigor can be related to differences in early bearing. Furthermore, even in these old
Hiroshi Iwanami, Shigeki Moriya, Nobuhiro Kotoda, and Kazuyuki Abe
, cultivar differences in weight loss (equivalent to water loss) of fruit during storage did not relate to those in the softening rate and the reduction rate of turgor in our study (data not shown). In conclusion, fruit softened with a reduction in turgor
Yun Kong and Youbin Zheng
transplanting ( Fig. 3 ). However, the significant cultivar differences were mainly observed during the latter stages rather than the former ones. Fig. 3. Sodium (Na) removal rate of ‘Green’ ( A ) and Golden’ ( B ) purslane grown in hydroponic solutions with
Hyung Jun Kim, Chris Harlow, and Mary Peet
The objective of this study was to compare nutrient ion uptake and growth of Lycopersicum esculentum Mill. cvs. Trust, widely grown in North America, and Momotaro, widely grown in Korea and Japan. Tomatoes were planted July 2004, two per pot, in 36 perlite-filled pots fertigated with modified Steiner solution in a closed system. Inorganic ions (K, NO3-N, Mg, P, S) in the nutrient solution were measured weekly. Weekly solution uptake rate for both cultivars increased from 70 mg·MJ-1 irradiance at 36 days to 200 mg·MJ-1 at 133 days (end of experiment). The uptake rate of `Trust' was lower than `Momotaro' until 92 days after planting, then higher for the remainder of the experiment. This corresponded to lower leaf area in `Trust' prior to 92 days, then greater leaf area than `Momotaro'. Similarly, the nutrient uptake rate (ppm) of K, Ca, Mg, and S ions in `Trust' were lower than `Momotaro' until 92 days and higher after 92 days. The P uptake showed the opposite pattern with a higher uptake rate in `Trust' than `Momotaro' until 92 days and lower uptake thereafter. The N uptake rate did not differ between the cultivars. Thus, except for P and N, uptake of individual ions was proportional to total nutrient solution uptake. Plant height, number of clusters and total leaf area at 133 days was higher in `Momotaro' but fruit number and total aboveground dry weight (leaf, stem, and fruit) was higher in `Trust'. Percentage of total dry weight, represented by leaf and fruit in `Momotaro', were 40% and 41%, respectively, and 30% and 57%, respectively in `Trust'.
Fumiomi Takeda, Bernadine C. Strik, Derek Peacock, and John R. Clark
Transition to reproductive development and subsequent development of floral primordia (e.g., sepals, petals, stamens, and pistils) were determined in several blackberry (Rubus subgenus Rubus Watson) cultivars (Boysen, Cherokee, Chester Thornless, Marion, and Thornless Evergreen) growing in one or more locations (Clarksville, Ark., Aurora and Hillsboro, Ore., and Kearneysville, W. Va.). Also, daily maximum, mean, and minimum temperatures were recorded at three sites (Clarksville, Aurora, and Kearneysville) for the September to April sampling period. In buds of `Boysen' and `Marion' from Oregon, sepal primordia were first observed in November and December, respectively. Further floral bud development continued into January. Sepal development in `Cherokee' buds occurred in October in Oregon and in December in Arkansas. At all three sites, the buds of `Chester Thornless' blackberry remained undifferentiated until spring. The average mean temperatures in Oregon were generally well above 5 °C during the bud sampling period, but were near 0 °C on most days from mid-December to January in Arkansas and from December to late-February in West Virginia. The phenology of flower bud differentiation varied among the cultivars and was strongly influenced by prevailing winter temperatures. The results suggest that the shortening day lengths of late summer trigger flower bud development in blackberry. Floral bud development in blackberry, once initiated, was continuous; however, periods of low temperature (<2 °C) can arrest development.
Xiaozhong Liu and Bingru Huang
Summer decline in turf quality of creeping bentgrass (Agrostis palustris Hud.) is a major problem in golf course green management. The objective of this study was to examine whether seasonal changes and cultivar variations in turf performance are associated with changes in photosynthesis and respiration rates for creeping bentgrass. The study was conducted on a USGA-specification putting green in Manhattan, Kans., during 1997 and 1998. Four creeping bentgrass cultivars, `L-93', `Crenshaw', `Penncross', and `Providence', were examined. Grasses were mowed daily at 4 mm and irrigated on alternate days to replace 100% of daily water loss. In both years, turf quality, canopy net photosynthetic rate (Pn), and leaf photochemical efficiency (Fv/Fm) were high in May and June and decreased to the lowest levels in July through September. Whole-plant respiration rate (R) and canopy minus air temperature (▵T) increased during summer months. In October, turf quality and Pn increased, whereas R and T decreased. During summer months, turf quality was highest for `L-93', lowest for `Penncross', and intermediate for `Providence' and `Crenshaw'. Seasonal changes and cultivar variations in turf quality were associated with the decreasing photosynthetic rate and increasing respiration rate.
Carrie H. Wohleb and Timothy D. Waters
a cold stimulus and the critical temperature varies depending on the cultivar ( Brewster, 2008 ), so it is not surprising that there were cultivar differences. The average number of bolters for cultivars ranged from 0.0 to 15.5 per plot, and averaged