Strawberry Growth and Photosynthetic Responses to Paclobutrazol

Abstract

<jats:p>Foliar sprays of increasing concentrations (0, 75, 150, 300, 600, and 1200 mg·liter<jats:sup>-1</jats:sup>) of paclobutrazol were applied to `Cardinal' strawberry plants <jats:italic>(Fragaria × ananassa</jats:italic> Duch.) 35 days after transplanting. The plants were established in August in cultivated plots for measurement of paclobutrazol effects on first year growth or in a double-row hill system on black polyethylene-covered raised beds for 2nd year measurements. Increasing the paclobutrazol concentration reduced the number of runners, decreased runner length, and limited biomass partitioned into daughter plants. By the end of the first growing season, paclobutrazol had increased lateral crown development but reduced leaf area per treated plant. Root growth was reduced by concentrations &gt;600 mg·liter<jats:sup>-1</jats:sup>. Treatment with 75 to 300 mg·liter<jats:sup>-1</jats:sup> increased total plant dry weight by 33% to 46%. The following spring, plant growth was decreased by ≥ 300 mg·liter<jats:sup>-1</jats:sup>. Yield was increased by all treatments, except 1200 mg·liter<jats:sup>-1</jats:sup>. Leaf net photosynthesis increased within 12 days after treatment with paclobutrazol and was higher than in the controls the next summer. Leaf stomata1 conductance also increased the first year and was significantly higher the 2nd year after treatment. The optimum concentration of paclobutrazol for strawberries appears to be between 150 and 300 mg·liter<jats:sup>-1</jats:sup>.</jats:p>

Response of Forsythia ×intermedia `Spectabilis' to Uniconazole. II. Leaf and Stem Anatomy, Chlorophyll, and Photosynthesis

“…While forsythia did not exhibit an increase in P N before 55 DAT, other researchers have demonstrated triazole-induced increases in P N for 'Cardinal' strawberry (Fragaria ×ananassa Duch.) within 12 DAT (Deyton et al, 1991). However, both strawberry (Deyton et al, 1991) and forsythia had higher levels of P N when measured on the new leaves produced the following growing season.…”

“…within 12 DAT (Deyton et al, 1991). However, both strawberry (Deyton et al, 1991) and forsythia had higher levels of P N when measured on the new leaves produced the following growing season. Increased chlorophyll concentration and decreased ratio of Chl a and Chl b resulting from uniconazole application may influence CO 2 exchange and assimilation and may contribute to the P N increase reported herein.…”

The Physiology of Flowering in Strawberry

“…AMO-1618 increased flower induction in SD cultivars grown under noninductive long days (Avigdori-Avidov et al 1977). This was attributed to a source-sink effect, either by promoting photosynthesis, thereby increasing assimilate availability (Deyton et al 1991) or by decreasing vegetative growth, resulting in increased assimilate partitioning to reproductive growth (Bish et aI., 1996). This was attributed to a source-sink effect, either by promoting photosynthesis, thereby increasing assimilate availability (Deyton et al 1991) or by decreasing vegetative growth, resulting in increased assimilate partitioning to reproductive growth (Bish et aI., 1996).…”

Prohexadione-calcium Decreases Fall Runners and Advances Branch Crowns of `Chandler' Strawberry in a Cold-climate Annual Production System

“…Published studies have indicated that runnering can be increased with applications of gibberellins (GA) (Kender et al, 1971;Tehranifar and Battey, 1997), cytokinins (Biain de Elizalde and Guitman, 1979;Hasse et al, 1989;Pritts et al, 1986;Waithaka and Dana, 1978) or combinations of these (Kender et al, 1971;Waithaka and Dana, 1978). As a result, a wide range of growth inhibitors targeting GA biosynthesis or response have been tested for suppression of runners (Archbold 1986(Archbold , 1989Bish et al, 1996;Deyton et al, 1991;Hasse et al, 1989;Ibrahim and Mohamed, 1993;McArthur and Eaton, 1987). Of these, the most consistently effective has been the strong biosynthesis inhibitor paclobutrazol (Archbold, 1989;Bish et al, 1996;Deyton et al, 1991).…”