Agronomy Journal Grow Your Career With ASA
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 QUICK SEARCH:   [advanced]


     


This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF) Free
Right arrow An erratum has been published
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Web of Science (5)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Beam, J. B.
Right arrow Articles by Johnson, P. D.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Beam, J. B.
Right arrow Articles by Johnson, P. D.
Agricola
Right arrow Articles by Beam, J. B.
Right arrow Articles by Johnson, P. D.
Related Collections
Right arrow Economics
Right arrow Other Crop Management
Right arrow Other Oil Crops
Right arrow Production Agriculture
Agronomy Journal 94:331-336 (2002)
© 2002 American Society of Agronomy

PRODUCTION PAPER

Influence of Prohexadione Calcium on Pod Yield and Pod Loss of Peanut

Joshua B. Beama, David L. Jordan*,a, Alan C. Yorka, Thomas G. Isleiba, Jack E. Baileya, Thomas E. McKemieb, Jan F. Spearsa and P. Dewayne Johnsona

a Dep. of Plant Pathol., Box 7619, North Carolina State Univ., Raleigh, NC 27695
b BASF Corp., 26 Davis Dr., Research Triangle Park, NC 27709

* Corresponding author (david_jordan{at}ncsu.edu)

Received for publication April 13, 2001.

    ABSTRACT
 TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 SUMMARY
 REFERENCES
 
Excessive vegetative growth of peanut (Arachis hypogaea L.) can make digging and inverting operations less efficient. Reducing vine growth by applying a suitable plant growth regulator would be an efficient way to manage peanut vines. Pod yield, market grade factors, and gross economic value of peanut treated with prohexadione calcium (calcium salt of 3,5-dioxo-4 propionylcyclohexanecarboxylic acid) were evaluated at 19 sites in North Carolina during 1999 and 2000. Experiments were also conducted at two locations each during 1999 and 2000 to determine the effect of prohexadione Ca, digging date, and lifting (shaking peanut vines after digging to remove soil before combining) on combined yield, market grade factors, gross economic value, seed germination, and pod loss of the virginia market-type cultivar NC 12C. Prohexadione Ca at 140 g a.i. ha-1, applied at 50% row closure and repeated 2 wk later, increased row visibility at harvest, pod yield by 310 kg ha-1, and gross economic value of quota peanut by $223 ha-1 when pooled over 19 sites. Prohexadione Ca increased combined yield by 220 kg ha-1 and decreased percent pod loss by 4% regardless of digging date and lifting treatment compared with nontreated peanut. Prohexadione Ca did not affect maximum yield (sum of pods remaining in soil and on the soil surface and pods that were combined) or germination of peanut seed. These data suggest that increased combined yield noted following application of prohexadione Ca can be partially attributed to decreased pod loss.

Abbreviations: %ELK, percentage of extra large kernels • %OK, percentage of other kernels • %SMK, percentage of sound mature kernels • %SS, percentage of sound splits • %TSMK, percentage of total sound mature kernels


    INTRODUCTION
 TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 SUMMARY
 REFERENCES
 
EXCESSIVE VEGETATIVE GROWTH of peanut can reduce digging efficiency and promote disease development in the canopy (Beasley, 1970; Henning et al., 1982). Digging peanut is difficult when equipment operators cannot distinguish rows. Daminozide [butanedioic acid mono (2,2-dimethyl-hydrazide)] was applied in the past to reduce internode length and vine growth (Brown and Ethredge, 1974; Gorbet and Rhoads, 1975; Hsi and Davidson, 1980). Although daminozide enhanced row visibility, yield response was inconsistent (Brown and Ethredge, 1974; Hodges and Perry, 1970; Mozingo and Steele, 1984; Wynne et al., 1974). There was a trend toward increased pod number per plant when daminozide was applied (Brown and Ethredge, 1974). Shorter gynophores and pods and fewer four-seeded pods were also noted in valenica-type peanut (A. hypogaea subsp. fastigiata Waldron var. fastigiata) treated with daminozide (Brown et al., 1973; Hsi and Davidson, 1980). Increases in fruit number per plant were found with apple (Malus spp.), grape (Vitis vinifera L.), broad bean (Vicia faba L.), and tomato (Lycopersicon esculentum Mill.) (Fisher and Looney, 1967; Looney et al., 1967; Read and Fieldhouse 1970; Tukey, 1970; Younis and Elnur, 1970) treated with daminozide. Registration for daminozide was cancelled in 1988.

Prohexadione Ca suppresses vegetative growth of apple, rice (Oryza sativa L.), tomato, grain sorghum [Sorghum bicolor (L.) Moench], wheat (Triticum aestivum L.), and oilseed rape (Brassica napus L.) (Byers and Yoder, 1999; Grossman et al., 1994; Lee et al., 1998; Nakayama et al., 1992; Yamaji et al., 1991). Prohexadione Ca inhibits gibberellin biosynthesis by blocking kaurene oxidase and also increases the level of abscisic acid and cytokinins in responsive species (Grossman et al., 1994). In vivo, the primary mode of action of prohexadione Ca is inhibition of 3ß-hydroxylation of GA20 to GA1 (Nakayama et al., 1992). In peanut, prohexadione Ca reduces vine growth, causes main stems to remain short, and enhances row visibility (Culpepper et al., 1997; Jordan et al., 2000; Mitchem et al., 1996). Culpepper et al. (1997) reported that prohexadione Ca increased earliness and pod yield and improves market grade characteristics of peanut in some but not all circumstances.

The mechanism of yield enhancement by prohexadione Ca has not been elucidated. Daminozide was suspected to reduce pod loss (Hodges and Perry, 1970). However, Bauman and Norden (1971) could not distinguish differences in gynophore strength when comparing nontreated and daminozide-treated peanut. Gardner (1988) found that the change in vegetative growth of peanut caused by daminozide did not alter partitioning of assimilates to pods. Determining if prohexadione Ca reduces pod loss may help explain the mechanism of yield enhancement.

Research was conducted to compare pod yield, market grade factors, and gross economic value of peanut treated with prohexadione Ca at multiple sites throughout North Carolina under a variety of conditions and to determine if increased pod yield following application of prohexadione Ca is associated with decreased pod loss.


    MATERIALS AND METHODS
 TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 SUMMARY
 REFERENCES
 
Multisite Experiment
The experiment was conducted at 19 sites on sandy loam to loamy soils throughout the Coastal Plain of North Carolina during 1999 and 2000. Peanut was planted in rows spaced 91 to 96 cm apart with plot size of four rows by 10 to 15 m. Pest management and production practices were standard for the region, and other than prohexadione Ca applications, they were administered uniformly over the entire experiment. The cultivars NC 10C, NC-V 11, and NC 12C were present at 3, 10, and 4 sites, respectively. The cultivars VA 98R and Perry were present at one site each during the 2-yr period. Planting date ranged from 5 to 24 May.

Prohexadione Ca was applied at 140 g ha-1 when 50% of peanut vines from adjacent rows were touching and was repeated 2 wk later at the same rate. A no-prohexadione Ca control was also included. Prohexadione Ca (Baseline, BASF Corp., Research Triangle Park, NC) was applied with a CO2–pressurized backpack sprayer calibrated to deliver 140 L ha-1 at 207 kPa. Twenty-eight percent urea ammonium nitrate (UAN) was applied with prohexadione Ca at 2.3 L ha-1.

The experimental design was a randomized complete block with treatments replicated four times at each site. Row visibility was estimated visually in mid-September 1999 or late August 2000 using a scale of 1 (flat peanut canopy with indistinguishable rows) to 10 (triangular-shaped, well-defined peanut rows) (Mitchem et al., 1996). The center two rows of each plot were mechanically dug and inverted and allowed to air-dry in the field for 4 to 10 d before harvest. Pods were mechanically combined (referred to as combined yield), and final combined yield was adjusted to 8% moisture. A 500-g sample of pods was removed from two of the four replicates to determine percentages of extra large kernels (%ELK), sound mature kernels (%SMK), total sound mature kernels (%TSMK), other kernels (%OK), and fancy pods (%FP) (Davidson et al., 1982). Market value ($ kg-1) was calculated using the USDA Farm Services Administration loan schedule for quota peanut during each year, with the average market value from the two replicates used to determine gross economic value ($ ha-1). Gross economic value was calculated as the product of combined yield and market value. Data for row visibility, combined yield, and gross economic value were subjected to analysis of variance. Means of the significant (P <= 0.05) main effects and interactions were separated using Fisher's Protected LSD Test at P = 0.05.

Pod-Loss Experiment
The experiment was conducted at the Peanut Belt Research Station in Lewiston, NC, and at the Upper Coastal Plain Research Station located near Rocky Mount, NC, during 1999 and 2000. Soils at Lewiston and Rocky Mount were a Norfolk sandy loam (fine-loamy, siliceous, thermic, Aquic Paleudults) and a Goldsboro sandy loam soil (fine-loamy, mixed, thermic, Arenic Hapludults), respectively. The cultivar NC 12C was planted in conventionally prepared seedbeds on 91-cm rows on 8 May 1999 at Lewiston, 24 May 1999 at Rocky Mount, 9 May 2000 at Rocky Mount, and 3 May 2000 at Lewiston. Pest management and production practices other than those for specific treatments were administered uniformly to the entire test and were standard for the region.

The experimental design was a randomized complete block with a split plot arrangement. Main-plot factors consisted of two digging dates (late September and mid-October). Subplot factors consisted of combinations of two lifting treatments (no lifting or one lifting operation) and two prohexadione Ca rates (0 and 140 g ha-1). Subplot combinations were replicated six times. Subplot size was four rows by 10 to 15 m long.

Prohexadione Ca was applied as described in the multisite experiment. Visual estimates of row visibility were also recorded as described previously. Height of three plants within each plot from the soil surface to top of main stems was recorded in late August 1999 and early September 2000. The average height of the three plants was considered the dependent variable.

Peanut was dug and combined as described previously. Peanut vines and pods were mechanically lifted 2 to 4 d after digging for the appropriate treatments. Pod yield, market grade factors, market value, and gross economic value were determined as described previously, except that all six replicates were used to determine market grades and economic value.

After digging and lifting but before combining, three plants from each plot were removed at random to determine the number of pods per plant (referred to as pod number), pod weight per plant (referred to as pod weight), and weight of each pod (referred to as individual pod weight). Individual pod weight was determined by dividing pod number by pod weight. Also, after digging and lifting but before combining, soil from a 1- by 1-m quadrant (in middle of a peanut-combining row) to a depth of 10 cm from each plot was sifted to collect pods remaining in the soil. Pods remaining on the soil surface for the entire plot were also collected. The combined weight of pods collected from the sifted soil and those remaining on the soil surface was considered lost during the digging and lifting operations or pods that shed before these operations (collectively referred to as pod loss). Mature pods can shed before digging if digging is delayed (Jordan et al., 1998). Theoretical maximum yield (referred to as maximum yield) was calculated as the sum of weights for combined yield and pod loss (kg ha-1). Percent pod loss was calculated as the ratio of pod loss to maximum yield.

A standard germination test was performed on seed from each plot. Seed came from those riding on the sound mature kernels screen (7.1 mm by 2.5 cm) during the shelling procedure. Before standard germination evaluation, seed were treated with a fungicide combination consisting of 45% captan (N-trichloromethylthio-4-cyclohexene-1,2-dicarboximide), 15% PCNB (pentachloronitrobenzene), and 10% carboxin (5,6-dihydro-2-methyl-N-phenyl-1,4-oxathin-3-carboxamide). Standard germination tests were performed on two 25-seed subsamples in rolled towels at alternating temperatures of 20 and 30°C, with 16 h at 20°C. Seedlings were evaluated 5 and 8 d after planting according to standard procedures (Association of Official Seed Analysts, 1999). Only those seedlings with normal development were considered germinated.

Based on preliminary F-tests, data were pooled over site x prohexadione Ca, site x lifting treatment, and site x prohexadione Ca x lifting treatment interactions to provide one error term for combined yield, maximum yield, pod loss, percent pod loss, pod number, pod weight, individual pod weight, %ELK, %TSMK, market value, gross economic value, and percent seed germination (C. Brownie, personal communication, 2001). This pooled error term (site x prohexadione Ca x lifting treatment) was used to test main effects of prohexadione Ca and lifting treatments and prohexadione Ca x lifting interactions. Also, site x digging date x prohexadione Ca, site x digging date x lifting treatment, and site x digging date x prohexadione Ca x lifting treatment interactions were pooled to provide one error term to test interactions of digging date x prohexadione Ca, digging date x lifting treatment, and digging date x prohexadione Ca x lifting treatment. Means of significant main effects and interactions were separated using Fisher's Protected LSD Test at P <= 0.05, using error terms for random and fixed effects (McIntosh, 1982).


    RESULTS AND DISCUSSION
 TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 SUMMARY
 REFERENCES
 
Multisite Experiment
The interaction of site (combination of location, cultivar, and year) x prohexadione Ca was noted for row visibility (P = 0.0001). An increase in row visibility occurred at 18 of 19 sites when prohexadione Ca was applied (data not presented). The magnitude of increased row visibility ranged from 2 to 6 (data not presented). Mitchem et al. (1996) and Culpepper et al. (1997) also reported increased row visibility when prohexadione Ca was applied.

When pooled over sites, prohexadione Ca increased combined yield over nontreated peanut by 270 (P = 0.2277), 330 (P = 0.0069), and 290 (P = 0.0590) kg ha-1 for the cultivars NC 10C, NC-V 11, and NC 12C, respectively (data not presented). Gross values of these respective cutivars were $249 (P = 0.1827), $203 (P = 0.0323), and $177 (P = 0.1065) ha-1 higher when prohexadione Ca was applied (data not presented). Although prohexadione Ca numerically increased yield of the cultivar Perry by 840 kg ha-1 (P = 0.1553), yield of the cultivar VA 98R was affected only slightly (50 kg ha-1 increase; P = 0.9014) (data not presented). Gross values of these respective cultivars were numerically increased by $580 (P = 0.1159) and $328 (P = 0.6134) ha-1 when prohexadione Ca was applied. This data set contained only one site each for the cultivars Perry and VA 98R, and additional research at multiple sites is needed to substantiate or refute these results.

Although variation in response to prohexadione Ca was noted when comparing cultivars, a combined analysis was preformed across sites and cultivars to determine a general response over a wide range of circumstances. The interaction of site x prohexadione Ca was not significant for combined yield (P = 0.7847). However, main effects of site (P = 0.0001) and prohexadione Ca (P = 0.0002) were significant. When pooled over sites, which included five cultivars and 11 locations, prohexadione Ca increased combined yield from 4160 kg ha-1 (nontreated peanut) to 4470 kg ha-1 (data not presented). Additionally, the interaction of site x prohexadione Ca was not significant for gross economic value (P = 0.8617). When pooled over sites, prohexadione Ca (P = 0.0003) increased gross economic value of quota peanut from $2950 ha-1 to $3180 ha-1 (data not presented).

Variation in peanut response to prohexadone Ca has been reported previously. Culpepper et al. (1997) reported a range of increased gross economic value of $290 ha-1 to $610 ha-1 when prohexadione Ca was applied. They also reported increased combined yields of 470, 590, and 510 kg ha-1 in two of four trials following application of prohexadione Ca to the cultivars NC 10C, NC-V 11, and NC 12C, respectively. Jordan et al. (2000) reported increased gross economic value of quota peanut ranging from -$300 to $800 ha-1 in 12 experiments conducted during 1997 and 1998. In other research, Jordan et al. (2001) reported increased gross economic value of quota peanut of $100 ha-1 following prohexadione Ca application when pooled over seeding rate–row pattern combinations and the cultivars NC-V 11 and NC 12C.

The cultivars and cultural practices used in these experiments are representative of production practices in North Carolina. NC-V 11 and NC 12C are the two most commonly grown cultivars in North Carolina (Spears, 2001). These respective cultivars accounted for 74% of the sites. Approximately 16% of the sites were irrigated. Toth (1998) reported that only 6% of peanut hectares in North Carolina are irrigated.

Pod-Loss Experiment
Prohexadione Ca increased row visibility at both locations during each year (data not presented). Row visibility was increased by 3 to 4 points on a scale of 10 points when prohexadione Ca was applied. Increased row visibility of the cultivar NC 12C has been reported when prohexadione Ca was applied (Culpepper et al., 1997).

Main stems were shorter at each location during both years when prohexadione Ca was applied (data not presented). Main-stem height was 10 to 20% shorter for prohexadione Ca–treated peanut compared with nontreated peanut. Other research (Jordan et al., 2000; Mitchem et al., 1996) has shown that main stems are shorter following prohexadione Ca application.

The interaction of site x prohexadione Ca x lifting was not significant for combined yield (P = 0.3331). However, the main effect of prohexadione Ca was significant (P = 0.0086). When pooled over sites, digging dates, and lifting treatments, prohexadione Ca increased combined yield by 220 kg ha-1 (Table 1). An increase in combined yield of 310 kg ha-1 was noted when prohexadione Ca was applied in the multisite experiment (data not presented).


View this table:
[in this window]
[in a new window]
 
Table 1. Effect of prohexadione Ca on combined yield, maximum yield, pod loss, and percent pod loss.{dagger}

 
The site x digging date interaction was significant for combined yield (P = 0.0014). When pooled over prohexadione Ca and lifting treatments, combined yield increased 10 to 14% at Rocky Mount in 1999 and 2000, respectively, when digging was delayed (Table 2). In contrast, combined yield was not affected by digging date at Lewiston in either year. Poor digging conditions at the second digging at Lewiston in 1999 resulted from excessive soil moisture and may have influenced the numerical decrease in combined yield when digging was delayed. In 2000, low temperatures during the period after the first digging date but before the second digging may have greatly reduced further pod maturation over this period of time (data not presented). These factors may explain lack of an increase in combined yield as digging was delayed. Pod yield often increases when digging is delayed (Mozingo et al., 1991; Wright and Porter, 1992) although environmental conditions can affect combined yield (Jordan et al., 1998).


View this table:
[in this window]
[in a new window]
 
Table 2. Effect of digging date on combined yield, percent pod loss, and actual pod loss.{dagger}

 
The site x prohexadione Ca x lifting interaction was not significant for maximum yield (P = 0.1461). When pooled over sites, digging dates, and lifting treatments, maximum yield increased by only 10 kg ha-1 when prohexadione Ca was applied (Table 1).

The interaction of site x digging date was significant for actual pod loss and percent pod loss (P = 0.0001). When pooled over prohexadione Ca and lifting treatments, pod loss increased at the second digging date at Lewiston in 1999 and 2000 and at Rocky Mount in 1999 (Table 2). Delaying digging at Lewiston in 1999 and 2000 and at Rocky Mount in 2000 increased percent pod loss. Increased percent pod loss would be expected when digging is delayed because the gynophore begins to senesce when the fruit reaches physiological maturity (Shushu and Cutter, 1990). This would mean a decrease in the strength of the gynophore at a later digging date. Additionally, pods later in the growing season are generally more mature and heavier and may shed more easily during the digging operation. At Rocky Mount in 1999, near-perfect digging conditions were present at the second digging date compared with the first digging date, and this most likely contributed to less pod loss during the second digging date.

The interaction of digging date x prohexadione Ca was significant for actual pod loss (P = 0.0095) and percent pod loss (P = 0.0348). When pooled over sites and lifting treatments, pod loss decreased at the second digging date by 340 kg ha-1, and at the first digging date, a numerical decrease was noted when prohexadione Ca was applied (Table 3). Percent pod loss also decreased at both digging dates when prohexadione Ca was applied. These data suggest that increased pod retention may be associated with increased combined yield when prohexadione Ca is applied. Less pod loss would be expected at the first digging date because fewer pods have reached full maturity and are less likely to shed naturally or due to digging or lifting.


View this table:
[in this window]
[in a new window]
 
Table 3. Effect of prohexadione Ca and digging date on actual pod loss and percent pod loss.{dagger}

 
A site x prohexadione Ca x lifting interaction was significant for pod weight (P = 0.0208) and pod number (P = 0.0205). When pooled over digging dates at Rocky Mount in 1999 and 2000, pod weight increased when prohexadione Ca was applied and peanut was lifted (Table 4). Pod weight was not affected by prohexadione Ca at Lewiston when peanut was lifted or at either location or year when peanut was not lifted. Pod number increased when prohexadione Ca was applied and peanut was not lifted at Rocky Mount in 1999 and Lewiston in 2000 (Table 4). At Rocky Mount in 1999, there was an increase in pod number when peanut was lifted and prohexadione Ca was applied. These data suggest that prohexadione Ca either leads to greater pod retention or that plants treated with prohexadione Ca have more pods. Although variation was noted among lifting treatments relative to pod weight and pod number, either statistical or numerical increases were noted for most comparisons when prohexadione Ca was applied. However, prohexadione Ca did not affect individual pod weight (P = 0.7218). These data suggest that prohexadione Ca does not influence actual pod weight and that increases in combined yield may be associated more with pods being held on plants rather than increased individual pod weight.


View this table:
[in this window]
[in a new window]
 
Table 4. Effect of site, prohexadione Ca, and lifting treatment on pod weight and pod number for individual plants.{dagger}

 
The interaction of site x digging date was significant for pod weight (P = 0.0008) and individual pod weight (P = 0.0028). Weight of pods per plant increased when digging was delayed at Rocky Mount in 1999 (data not presented). When pooled over prohexadione Ca and lifting treatments, individual pod weight increased when digging was delayed at Rocky Mount and Lewiston in 1999 (data not presented). These data also support previous research demonstrating that delaying digging may increase individual pod weight (Mozingo et al., 1991).

A site x digging date interaction was significant for %TSMK (P = 0.0313), %ELK (P = 0.0145), market value (P = 0.0378), gross economic value (P = 0.0022), and percent seed germination (P = 0.0212). When separated by site and pooled over prohexadione Ca and lifting treatments, %TSMK increased when digging was delayed at Lewiston in 2000 (Table 5). The %TSMK did not differ among digging dates at the other sites. The %ELK was higher at Rocky Mount and Lewiston in 2000 at the later digging date (Table 5). There was no difference in %ELK between digging dates in 1999 at either location. This may have been a result of excessive soil moisture at Lewiston at the later digging date in 1999, which may have slowed maturity of peanut and caused shedding of the more mature pods. At Rocky Mount, soil conditions at the second digging date were more conducive to minimizing pod loss compared with those at the first digging date at this location in 1999.


View this table:
[in this window]
[in a new window]
 
Table 5. Effect of digging date on market grades, market value, and gross economic value.{dagger}

 
When pooled over prohexadione Ca applications and lifting treatments, market value increased at Lewiston in 2000 when digging was delayed (Table 5). Market value did not differ among digging dates at the other three sites. Gross economic value was higher at Rocky Mount in 1999 and 2000 when digging was delayed (Table 5).

When separated by sites, percent germination decreased at Rocky Mount in 1999 (87 vs. 67%) and in 2000 (93 vs. 62%) when digging was delayed (data not presented). At Lewiston in 1999 or 2000, percent seed germination did not differ among digging dates (data not presented). Prohexadione Ca did not effect germination at either location or year (data not presented).


    SUMMARY
 TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 SUMMARY
 REFERENCES
 
Peanut responded favorably to later digging, provided that weather conditions were conducive to prevent pod loss. Prohexadione Ca increased combined yield irrespective of digging date and lifting treatment at all sites in the pod-loss experiment. Likewise, prohexadione Ca increased combined yield in the multisite experiment. A 310 kg ha-1 increase was noted when prohexadione Ca was applied when data were pooled over the 19 sites in the multisite experiment. However, variation in magnitude and significance of response was noted among cultivars. A 220 kg ha-1 increase was noted when prohexadione Ca was applied when data were pooled over sites, digging date, and lifting treatment in the pod-loss experiment. This correlates with a 210 kg ha-1 decrease in pod loss when pooled over these treatment factors. Prohexadione Ca did not affect germination of peanut seed, individual pod weight, %TSMK, %ELK, or market value. However, prohexadione Ca did increase row visibility, and it decreased percent pod loss at both digging dates and actual pod loss at the second digging date. It is possible that gynophores were more strongly attached to the peanut pod and to the auxiliary branch of the peanut plant following prohexadione Ca application, which may have resulted in reduced digging losses and pod shedding.

Enhanced maturity and increased %ELK of peanut treated with prohexadione Ca was noted by Culpepper et al. (1997). This was not fully supported by our research. Culpepper et al. (1997) based their conclusion concerning enhanced earliness of pod maturation on differences in percentages of black, brown, orange, yellow, and white pods using mesocarp color determination (Young et al., 1982). We did not perform mesocarp color determinations in these studies. Although a higher percentage of black and brown pods following applications of prohexadione Ca at a specific point in time compared with nontreated peanut suggests enhanced earliness, a higher percentage of dark pods may also suggest greater pod retention. Plants retaining a higher percentage of mature pods most likely would show a higher percentage of dark pods when comparing mesocarp color. We found increased pod retention from the application of prohexadione Ca. However, it is possible that a combination of pod retention and enhanced maturity of peanut may be responsible for the yield increase noted following prohexadione Ca application.

Cultivar and environmental conditions have been shown to influence efficacy of plant growth regulators (Brown and Ethredge, 1974; Culpepper et al., 1997; Jordan et al., 2000). The multisite experiment data shows that prohexadione Ca, on the whole, increased yield across a wide range of edaphic and environmental conditions and with different cultivars.


    ACKNOWLEDGMENTS
 
BASF Corporation provided financial support. Carl Murphy, Brenda Penny, Ming Hui Sun, and Shawn Askew provided technical support. Dr. Cavell Brownie assisted with statistical analyses. Appreciation is expressed to county farmers and Cooperative Extension Service agents for assistance with these studies as well as personnel at the Upper Coastal Plain Research Station and Peanut Belt Research Station.


    REFERENCES
 TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 SUMMARY
 REFERENCES
 




This article has been cited by other articles:


Home page
Agron. J.Home page
R. B. Sorensen, R. C. Nuti, and C. L. Butts
Yield and Plant Growth Response of Peanut to Midseason Forage Harvest
Agron. J., August 31, 2009; 101(5): 1198 - 1203.
[Abstract] [Full Text] [PDF]


Home page
Agron. J.Home page
D. L. Jordan, J. S. Barnes, C. R. Bogle, R. L. Brandenburg, J. E. Bailey, P. D. Johnson, and A. S. Culpepper
Peanut Response to Cultivar Selection, Digging Date, and Tillage Intensity
Agron. J., March 1, 2003; 95(2): 380 - 385.
[Abstract] [Full Text] [PDF]


This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF) Free
Right arrow An erratum has been published
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Web of Science (5)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Beam, J. B.
Right arrow Articles by Johnson, P. D.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Beam, J. B.
Right arrow Articles by Johnson, P. D.
Agricola
Right arrow Articles by Beam, J. B.
Right arrow Articles by Johnson, P. D.
Related Collections
Right arrow Economics
Right arrow Other Crop Management
Right arrow Other Oil Crops
Right arrow Production Agriculture


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
The SCI Journals Crop Science Vadose Zone Journal
Journal of Natural Resources
and Life Sciences Education
Soil Science Society of America Journal
Journal of Plant Registrations Journal of
Environmental Quality
The Plant Genome