economical scale. Strawberry cultivars are classified as seasonal-bearing (“short-day”; SB) and ever-bearing (“long-day” and “day-neutral”; EB). These classifications are based on the photoperiodic flowering response under field conditions. SB cultivars
Xiaonan Shi, Ricardo Hernández, and Mark Hoffmann
C.A. Weber, K.E. Maloney, and J.C. Sanford
Emma Bradford, James F. Hancock, and Ryan M. Warner
been reported for everbearing varieties, responding as qualitative LD plants at high temperatures (>25 °C), quantitative LD plants at lower temperatures (10 to 25 °C), and DN at temperatures below 10 °C ( Nishiyama and Kanahama, 2000 ; Sønsteby and
Kaitlyn M. Orde, Rich Marini, Kathleen Demchak, and Rebecca Sideman
yield and fruit number, suggesting the cultivar is a quantitative long-day plant. For this reason, some prefer the more general terms “remontant,” “repeat fruiting,” and “everbearing,” but these terms are less widely known, may confuse growers, carry
Kaitlyn M. Orde and Rebecca Grube Sideman
Scientia Hort. 130 2 795 810 Durner, E.F. Barden, J.A. Himelrick, D.G. Poling, E.B. 1984 Photoperiod and temperature effects on flower and runner development in day-neutral, junebearing, and everbearing strawberries J. Amer. Soc. Hort. Sci. 109 396 400
Jean-Pierre Privé and J. Alan Sullivan
Growth rates for two types of tissue-cultured plant stock for `Heritage', `Ruby', and `Redwing' red raspberry (Rubus idaeus L.) were examined. Actively growing plantlets from the greenhouse (G) were compared to cold-treated (CT) plantlets from cold storage. The greatest differences between these two occurred during the first 6 weeks after planting. At 4 weeks, CT plants for all cultivars had longer canes and internodes, sometimes twice that of G plants. Although `Heritage' had greater total plant dry weights following chilling, `Ruby' and `Redwing' had less. Chilling had no effect on `Heritage' root growth but did reduce root dry weight for `Redwing' and `Ruby'. Relative growth rate (RGR) and leaf area ratio (L-AR) were more effective variables for analyzing growth as they considered differences in initial biomass and cane number and provided a better representation of the data during the initial 6 weeks of growth. All cultivars showed a greater total plant RGR and LAR for the CT plants at 6 weeks. During the first 4 weeks, the G plants were more efficient producers of root dry matter while the CT plants were more efficient producers of cane dry matter. By 6 weeks, the G plants had partitioned a greater percentage of their assimilates into cane growth while the leaves, canes, and roots of the CT plants contributed equally to total RGR. No difference in total or individual component RGR was observed after 6 weeks.
Douglas V. Shaw
Selfed progenies were generated using 10 day-neutral genotypes from the University of California (UC) strawberry breeding program as parents and their offspring were classified for late-summer flowering response. The grandparents of each selfed progeny included one of four day-neutral genotypes and one of eight short-day genotypes. Under the null hypothesis of genetic control by a single locus with the allele for day-neutrality dominant to the allele for short-day flowering response, all of these day-neutral parent genotypes must be heterozygous and their selfed offspring were expected to fit a 3:1 ratio of day-neutral: short-day phenotypes. The percentage of day-neutral offspring observed over all progenies was 70.9%, and was significantly smaller than the expected value of 75% (χ2 1 = 5.08, P < 0.02). The percentage of day-neutral offspring for individual progenies ranged from 41.4% to 84.8%, and highly significant heterogeneity was detected among progenies (χ2 9 = 40.3, P < 0.01). Selfed progeny means for the cumulative late-summer flowering score calculated using the day-neutral fraction of offspring varied from 1.31 to 2.35 and progeny means for the number of inflorescences per plant ranged from 3.5 to 9.9; these differences among progenies were highly significant (P < 0.01). These observations can be used to conclusively reject the hypothesis that day-neutrality in this domestic strawberry population is controlled by a single locus.
Grant E.M. Matheke, Patricia J. Wagner, and Patricia S. Holloway
Yields of `Quinault' everbearing strawberries were compared during three seasons for plants grown under eight different mulch treatments with or without polyethylene row covers. In 1987, yields using clear polyethylene mulch with or without row covers (3.81 kg/m2 and 3.45 kg/m2, respectively) were significantly greater than all other mulch, treatments. Yields ranged from 1.05 kg/m2 to 2.60 kg/m2 for black polyethylene; black over white two-sided, embossed polyethylene; black latex liquid; permeable landscape fabric; white over black two-sided, embossed polyethylene mulch, all with row covers or the unmulched control plot without a row cover. During the second year, yields using clear polyethylene mulch were significantly greater than all treatments except for black polyethylene (5.32 kg/m2 and 4.74 kg/m2, respectively). Yields for the other mulch treatments ranged from 3.55 kg/m2 to 3.85 kg/m2. The summer of 1988 was warmer than average which may account for the improved performance of the black polyethylene mulch. In 1989 results were similar to 1987 in which the clear polyethylene mulch had significantly higher yields (5.66 kg/m2) than all other mulches (2.12 - 4.31 kg/m2). Clear polyethylene mulch with or without row covers is recommended for everbearing strawberry production in Alaska,
M.E. Pérez de Camacaro, G.J. Camacaro, P. Hadley, N.H. Battey, and J.G. Carew
The differences in growth and yield in the Junebearing strawberry (Fragaria ×ananassa Duch.) `Elsanta' and the everbearing `Bolero' and `Everest' were evaluated under field conditions. The seasonal patterns of radiation use efficiency and assimilate partitioning were also studied. Growth, development and yield showed considerable differences among cultivars. `Elsanta' showed the highest and `Bolero' and `Everest' the lowest values for almost all the vegetative parameters (leaf area, leaf dry weight, runner number). `Elsanta' produced large leaves and few crowns per plant in contrast to the everbearing cultivars which had more but smaller leaves and a larger number of crowns per plant. The production of flowers by `Elsanta' was concentrated in June with fruit production following in July. `Bolero' and `Everest' produced more than one flush of flowers during the season and fruited until October. As a result, yields of `Bolero' and `Everest' were greater than `Elsanta'. The higher yields of `Bolero' and `Everest' also reflected the greater number of crowns produced by these cultivars. The maximum intercepted and absorbed photosynthetically active radiation (PAR) occurred between July and August when the three cultivars showed the greatest increase in vegetative growth. Harvest index clearly differed among cultivars and this was related to the duration of cropping. The greatest harvest indexes were found for `Bolero' and `Everest'.
Lusike A. Wasilwa, Grace W. Watani, N. Ondabu, A. Nyaga, B. Kagiri, and S. Kiiru
Although macadamia was introduced to Kenya in 1946, it was not until the 1960s that commercial cutlivation commenced in the central, eastern, and western highlands. In the 1970s, 300 macadamia trees in the Central and Eastern highlands were selected based on nut yield and tree characteristics. In 1981, a subset of 25 of the most outstanding macadamia clones were planted (1979–1987) and evaluated at the National Horticulture Research Centre in Thika. Trial orchards, consisting seven to 15 clones (EMB-1, EMB-2, EMB-H, KMB-1, KMB-3, KMB-4, KRG-1, KRG-3, KRG-4, KRG-15, MRG-1, MRG-20, MRG-24, MRU-25, and TTW-2), were established in 1982, 1986, and 1989. The trials were set up as RCBD with five blocks and three to eight plants of each clone per block. Results from trial orchards show that macadamia hybrids (a natural hybrid between M. integrifolia and M. tetraphylla) EMB-H, KMB-3, and KMB-4 perform well at the higher elevations (>1700 m). The most outstanding clones of M. integrifolia with wide adaptability (1400 to 1750 m) were EMB-1, KRG-15, and MRG-20. Three distinct nut-bearing patterns [single peak (most varieties), bimodal peak, and ever-bearing] were observed. Nut clusters contain an average of 10 nuts (M. integrifolia) or 25 nuts (macadamia hybrid). Ten-year-old trees yield between 30 to 60 kg of nuts a year with kernel recovery of 28% to 41%.