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SARE Grant Project Hardy Kiwi Pollenation & Production
Final Project Report
The
purpose of this project was to address different pollenation
techniques in hardy kiwi, actinidia
arguta, Due to an early spring frost in the 2000 season, there was not ample spur material available, only secondary bud, to complete the research outlined in the grant proposal. We requested and received an extension until the 2001 season. Data was accumulated and submitted in an interim report for the 2000 season. This project entailed a three pronged approach conducting research trials which A) identified male cultivars that were best suited for use in the arbor based on their vigor and viability, and B) experimented with both biological and mechanical methods of pollen dispersion for female cultivars. HARDY KIWI MALE CULTIVAR STUDY
The
purpose of the male component of this study was to identify vigorous
and viable male cultivars suitable for use in commercial production
plantings.
Seven
male cultivars were listed in the original grant for test trials.
They were the Cornell, Fave, 74-32, 74-46, 127-40, Meader, and
Ivan males.
Two of the varieties listed in the original grant were assimilated. We found that two of the cultivars matched other male vines in the study, even though bearing a different name. Without the capability to test for individual genetic markers, these were omitted based on statistical data i.e.: leaf shape, petiole color, flower stem pattern, flower pollen nodule color, and wood characteristics. Those assimilated were the 127-40 that matched the Meader male, and Ivan which matched the 74-32 male. The proposed statistics, pollen viability, flower density, and new growth characteristics, were collected for the five remaining male cultivars Cornell, Fave, 74-32, 74-46, and Meader. Two vines in the study represented each male cultivar. One spur, twelve inches in length, was marked on each vine providing data from a total of 10 spurs. One “terminating” and one “non-terminating” spur represent each cultivar in the trial. A non-terminating spur is a single long green shoot with flower stems and flowers growing directly from it, in patterns of seven flowers, at the leaf nodules. A terminating spur is a shoot with short multi-lateral shoots extending from it. Flowers grow at the leaf nodules, in patterns of seven, on the multi-lateral shoots.
" Non-terminating Spur "
" Terminating Spurs " Terminating spurs will generally produce a heavier flower density; therefore, one spur of each type was chosen for each male cultivar to provide a good overall average for that cultivar’s performance. A male flower, once open, is viable for a period of one day. Flowers were collected from each vine at what we call the “popcorn stage”, right before opening. This process was carried out from June 4th through June 8th collecting one variety of male flowers per day. The flowers were opened individually, by hand, and tweezers were used to remove the pollen nodules from the flowers. The pollen nodules were then dried, packaged, and placed in frozen storage for pollen viability testing. MALE DATA FINDINGS: The goal was to identify the vigor of the A. arguta male vines in this study that would be suitable to achieve successful pollenation in commercial production. The A. arguta male cultivars tested have revealed both strengths and weaknesses. The results are as follows: POLLEN VIABILITY: Dr. George Davis at Bloomsburg University, Bloomsburg, PA, tested pollen viability, the amount of live pollen produced by each male cultivar. Dr. Davis tested for pollen viability by using stained flurscein, a diacetate, vital dye that does not glow. The dye is hydrophobic and penetrates the cell membranes of the pollen. The diacetate dye is then acted on by asterace, which liberates the pollen and converts it to flurscein, and allows the live pollen to glow a very bright green. Flurscein is measurable at 535 nanometers and by an actinic wavelength of 493 nanometers. The results for the five male cultivars in our trial are as follows
Graph No. 1
The pollen
viability, shown in Graph No. 1, was very good for the A. arguta male
varieties tested. Four cultivars, Cornell, Fave, 74-46, and Meader
achieved 80% to 90% viability. These levels are acceptable for commercial production in that
they meet and/or exceed the viability of A. deliciosa pollen
that can be purchased on today’s market.
The exception was the 74-32 cultivar, which only displayed 60%
viability. FLOWER DENSITY & FLOWERING SCHEDULES: The numerical information collected for the two vines of each cultivar was added together and averaged to provide the final data for those cultivars results. Flower schedules were documented daily for each of the ten test spurs. The chart below shows the individual male cultivars, their respective flower densities, and opening progression schedules.
Graph No. 2
Flower
density, shown in Graph No. 2, indicates that the 74-46, and 74-32
males displayed a high populous of flowers from the early to mid
flowering period. These males would pair nicely with the early
flowering female cultivars of Red Princess, Geneva, and Michigan.
The Cornell, Fave, and Meader males began with a lower populous
of flowers and achieved higher levels from the middle to end of the
flowering period. These
males would provide pollenation coverage for both the end of the early
female cultivars and the entire cycle for the later flowering
Ananasnaya cultivar.
NEW
GROWTH:
Each of the
trial spurs were cut back to one inch of the cordon or lateral cane
that it had grown from, at the end of flower bloom.
Annual replacement growth was documented, at the end of the
growing season, for each spur in the test group by measuring any new
growth that occurred.
One
terminating and one non-terminating spur were chosen for each cultivar
to allow a proper representation. Replacement growth is always more prominent on cane that
supports a non-terminating spur. A terminating spur when cut back will
at best produce a short, second year spur growth.
Graph No. 3
The 2001
growing season entailed an unseasonably long wet spring, warmed up
during the middle of flower to excessive temperatures, and then
remained hot and dry for the rest of the season. These conditions promoted a shorter, more condensed flowering
schedule, a total of five days less than in the 2000 season.
It also prompted an abundance of flower on the vines, which
resulted in less annual replacement growth. In summary, each of the male cultivars studied here are vigorous, with perhaps the exception of the 74-32, and provide a viable pollenation source, flower density, annual growth, and would be of value for a commercial production planting. It would be worthwhile to conduct a replicate study on the 74-32 vines for another growing season before eliminating it from the category of a vigorous male vine. Individual spur information providing the number of clusters, number of flowers per cluster, flower schedules, and new spur growth are available upon request.
HARDY KIWI FEMALE CULTIVAR STUDY INFORMATION
“Arguta female flowers”
This trial was separated into two test areas. Site #1: Pollen introduced into honeybee hives, and Site #2: Mechanical application of pollen. It is important to note that once a female flower has opened, it is able to receive pollen for a period of five to seven days. Female cultivars chosen for the trials in the original proposal were Ananasnaya (Anna), Geneva, Michigan, and Red Princess. Each female cultivar was to be represented by four vines interspersed throughout the arbor on each test site. Due to the damage sustained in the 2000 season spring frost, there were not ample Anna vines in each location on which to conduct studies. Therefore, one Anna vine was utilized in each location, and we included the female cultivar Fave that was represented by three vines in each location to maintain the original count of thirty-two vines in the study. POLLEN TYPES (A. Deliciosa): Pollen was purchased from Pollen Collection & Sales in Lodi, California, and The Pollen Bank in Bakersfield, CA., which are the only two sources for this type of pollen in the United States. Deliciosa kiwi pollen must be stored in a frozen state until use. Pollen that is taken out of frozen containment is only viable for a period of up to three hours.
Three
types of pollen were used for mechanical application.
All had an 85% viability or better. Type One - contained a mixture of pollen and anthers. This proved hard to distribute due to the anthers blocking the applicator. This pollen seemed to have the least effect. Type Two - contained 100% pollen without anthers. This pollen, which provided very satisfactory results, was easily dispersed but would be costly to do large areas with proper coverage. Type Three - contained 50% pollen, and 50% lycopodium. Lycopodium is a clay material that is used as an extender for pollen. This mixture produced good results, was easily dispersed, and would be the most cost effective to use in a commercial arbor.
WEATHER CONDIITIONS DURING FLOWER: Weather conditions were documented, in Fahrenheit degrees, on a daily basis during the flowering period and were as follows:
SITE #1: POLLEN INTRODUCED INTO HONEYBEE HIVES The number of female cultivars represented were (1) Anna, (3) Fave, (4) Geneva, (4) Michigan, and (4) Red Princess equaling sixteen vines total. Two spurs were marked on each vine providing data from a total of 32 spurs. Flowers were counted on each spur, and flower schedules were documented on a daily basis. The aisle and buffer areas in this test location were mowed to reduce competitive flowering plants. Those noted were dandelion and clovers. Honeybee hives were rented from Aucker’s Apiary, Bloomsburg, PA. This firm is reputable for their honeybees that are contracted annually from Maine to Florida. Twelve (12) honeybee hives were introduced into the arbor, at 20% flower bloom on June 5th. Five (5) grams of A. deliciosa pollen (Type Two - 100% pollen without anthers) was added to the hives and/or hive porches on four separate occasions so that the bees would be carrying male kiwi pollen before coming in contact with female flowers. HONEYBEE ACTIVITY: Firstly, it is of importance to note that A. arguta, hardy kiwi flowers contain pollen but do not contain nectar. According to apiary sources, honeybees will “work” flowers without nectar if placed in the arbor at a 20% or higher flower bloom. Hives were observed on a daily basis to document the amount of kiwi pollen carried by the bees. Kiwi pollen can be distinguished from other types of pollen in that it is pure white. The pollen of multi-flora rose is orange for example. “Honeybees carrying kiwi pollen” The majority of honeybees lost interest in the kiwi flowers within 24 hours of their introduction into the arbor. A minimal number of bees, out of approximately twenty, were observed carrying pollen back to the hive the first day, and one to two bees, out of approximately fifty, the second day.
The
A. deliciosa pollen, when added to hives or hive porches,
seemed
to irritate the honeybees and no
bees were observed returning with kiwi pollen from the vines. During flower, which lasted approximately eight days, no more than two honeybees were observed on a female cultivar at one time, yet pollenation in the arbor did take place. Weather conditions also play a major role in the activity of honeybees. The owners of the apiary confirmed that honeybees do not like, and generally will not work well in, overcast conditions.
FEMALE DATA FINDINGS – HONEYBEES WITH ADDED POLLEN The numerical information, collected for the spurs of the four vines of each cultivar, were added together and averaged to provide the final data for that cultivar’s results which are displayed in the following graphs.
Graph No. 4 Graph No. 4 identifies June 8th, as the peak of female flower production. The weather conditions from June 5th, when the bees were introduced through June 12th, varied in temperature, were generally overcast, and not conducive to bee activity.
Male
cultivars, however, in another location ¼ of a mile away, were
beginning to reach their peak flower activity on June 11th.
Due to the documentation of minimal bee interaction with the kiwi vines and little or no pollen being returned to the hives, it is obvious that air born pollen from the male vines in another arbor was responsible for the pollenation of the female vines in Test Location #1.
Graph No. 5 The successful percentage of pollenation that occurred in the trial spurs is shown in Graph No. 5. All female cultivars, with the exception of the Michigan, displayed an eighty percent or better success rate in carrying the original number of flowers pollenated through to the fruit harvest stage. Individual spur information providing the number of flowers per spur, flowers pollenated, fruit set, fruit drop, fruit yield, successful percentage of pollenation, and flower schedules are available upon request.
SITE #2: POLLEN INTRODUCED BY MECHANICAL APPARATUS The number of female cultivars represented were (1) Anna, (3) Fave, (4) Geneva, (4) Michigan, and (4) Red Princess equaling sixteen vines total. Two spurs were marked on each vine providing data from a total of 32 spurs. Flowers were counted on each spur prior to opening and were documented. The spurs were covered on June 3rd, with white No. 7 bags, to prevent pollen contamination from any other source. Due to the compressed flowering schedule, created by seasonal conditions, spurs were pollenated with 50 grams of A.deliciosa (Type One – pollen with anthers, and Type Three – 50% pollen/50% lycopodium) on three separate occasions rather than the four occasions outlined in the original proposal. A pneumatic pollen dispenser was used to distribute the pollen. The flower progression was documented when the bags were removed to pollenate the spurs. Bags were removed, after a ten-day period, on June 13th and the number of flowers pollenated, fruit set, fruit drop, and fruit yield were documented. NOTATION ON USE OF NO. 7 BAGS
“Female spurs covered with No. 7 bags” A large percentage of fruit drop occurred in this test trial. The covered spurs had a delayed flower opening in comparison to the flower schedule for the rest of the vine. Some mold was evident on flowers, and some previously pollenated flowers were aborted. We attribute this to the spurs being bagged during high temperature, and high humidity weather conditions as well as the added suppression of light available to the spurs.
FEMALE DATA FINDINGS – POLLEN APPLIED BY
MECHANICAL APPARATUS The numerical information collected for the spurs of the four vines of each cultivar were added together and averaged to provide the final data for that cultivar’s results.
Graph No. 6 Graph No. 6 indicates the flower progression of the spurs that were covered with No. 7 bags. The evidence that the covered spurs experienced a delayed schedule, due to the lower volume of light, is evident when compared to the female flower progression for the honeybees, in Graph No.4 on page 7, that indicates that peak flower actually occurred on June 8th. Due to the large percentage of flower/fruit drop that occurred with spurs covered by No. 7 bags, the data for uncovered spurs, from the same test vines, was documented to show the actual performance of mechanical pollenation.
Graph No. 7 Graph No. 7 indicates the successful percentage of yield, for both bagged spurs and non-bagged spurs, which confirms that mechanical pollenation does produce desirable results. Individual spur information providing the number of flowers per spur, flowers pollenated, fruit set, fruit drop, fruit yield, successful percentage of pollenation, and flower schedules are available upon request.
POLLENATION
METHOD COMPARRISON The goal of this project was to test both biological (bees), and mechanical methods of pollen dispersion, to determine which of the supplemental methods would increase and/or achieve successful pollenation of A. arguta female cultivars, and which method would be more cost effective for the grower. FRUIT PRODUCTION PER METHOD
Graph No. 8 shows the results of one representative vine of each cultivar, from each study group that was harvested, to provide the total amount of poundage produced by each pollenation method. Since the bees were not returning with kiwi pollen, or visible on location throughout the test trials, it is apparent pollenation occurred from an outside source. QUALITY & CHARACTERISTICS OF FRUIT The quality and characteristics of the fruit harvested was to be evaluated on the uniformity of size, weight, and marketable quality. There was no noticeable difference in the quality and characteristics of the fruit harvested from the two test locations.
Graph No. 9 Graph No. 9 indicates the successful percentage of fruit harvested from test spurs for the methods utilized in this study. The results indicate that mechanical pollenation provides more consistent results for a variety of female cultivars. In summary, mechanical pollenation also allows the grower “site specific” application to meet his individual pollenation needs. Also, this method is more cost effective. It does not require the rental of honeybee hives and the purchase of pollen to be placed in the hives. |
