Euphytica 30 (1981) 653-657

HERITABILITY OF CUT-FLOWER VASE LONGEVITY IN GERBERA

JAMES HARDING, THOMAS BYRNE and ROBERT L. NELSON

Department of Environmental Horticulture, University of California, Davis, CA 95616, USA

Received 3 October 1980

INDEX WORDS

Gerbera jamesonii, gerbera, heritability, cut-flower, vase longevity, Davis Population

SUMMARY

Estimates of broad-sense heritability for cut-flower vase longevity were 36 and 46 percent for a sample of Gerbera clones. Estimates of narrow-sense heritability for vase longevity were 0, 24 and 38 percent over 3 generations ofthe Davis Population. Response to selection for this character in this population is expected to be slow.

INTRODUCTION

Heritable variation for cut-flower yield in Gerbera has been reported by MAURER & HORN (1967) BORGHI & BALDI (1970), and MUCENIECE et al. (1978). Estimates of broad-sense and narrow-sense heritability and a positive response to selection for cut- flower yield has been reported for the Davis Population of Gerbera (HARDING et al., 1981). Estimates of general and specific combining ability for inflorescence characters have also been reported (MUCENIECE et al., 1978). While numerous studies have focused on physiological aspects of production and cut-flower vase longevity of ger- bera (e.g. BYRNE, 1973 ; LEFFRING, 1973 ; DE JONG, 1978 ; VAN MEETERING, 1978a, 1978b, 1979a, 1979b), the heritability of this character has not been established. The purpose of this investigation was to estimate heritability for cut-flower vase longevity in the Davis Population of gerbera.

MATERIALS AND METHODS

The details of the establishment, maintenance and mating scheme of the Davis Population are presented in HARDING et al. (1981). Because the population was com- posed of half sib families, flowers (inflorescences) could be picked from a given plant, from its half-sib, and from unrelated plants. The sampling of plants from the popu- lation was not random. Only plants with higher yields and acceptable flower and stem quality were tested for vase longevity. The population data in Table 1 indicate that 23 percent of the population was sampled in generation 1 and 26 percent was sampled in generation 2. Thus, there is the possibility these samples have less genetic variance than does the population and that estimates of narrow-sense heritability (h’) might be biased downwards.

In addition, 3 clonal divisions were made of each of 15 genetic stocks in 1972 and 2

653

1. HARDING. T. BYRNE AND R. L. NELSON

Table 1. Population sizes and numbers of plants selected for three characters for three generations for the Davis Population of gerberas.

Number of plants selected from population for

Generation Size of population

Productivity Productivity + quality

Productivity + quality + vase longevity

1 164 73 (45 %I 56 (34 %I 38 (23 76) 2 185 85 (46 %I 64 (35 %I 49 (26 %) 3 196 - -

clonal divisions were made of each of 26 genetic stocks in 1973. These were used to estimate broad-sense heritability (Hz). These samples include some of the parents of the Davis Population, not genotypes sampled from it. Consequently h2 and HZ are not estimated from the same population and are, therefore, not comparable.

Flowers with two rows of visibly mature stamens were harvested and placed ran- domly in glass jars containing deionized water. Temperature was maintained at 21 “C, and daytime lighting from 8:00 AM to 5:00 PM was ca 100 lux from cool white florescent tubes. Flowers were observed each day until they reached a stage of un- acceptable quality, determined subjectively on the occurrence of petal or stem wilt. The number of days in the laboratory was used to estimate cut-flower vase longevity (VL). Three flowers from each plant were evaluated and mean VL for each plant was analyzed by a linear analysis of variance. Components of variance were estimated and used, in turn, to estimate h2 and H2.

RESULTS

The distribution of VL for the original parents of the Davis Population and the distribution of VL for generations 1,2, and 3 are presented in Fig. 1. Mean VL in every case is over 10 days and approaches 2 weeks in generation 3. There was, however, a large variation in each sample, with some flowers lasting only 3-5 days and some lasting as long as 3 weeks.

The results of the analysis of variance on VL for clonal parents and estimates of HZ are presented in Table 2. They indicate that broad-sense estimates of heritability are in the intermediate range, ca. 40 percent.

Estimates of narrow-sense heritability (h’) are presented in Table 3. They are based on the expectation that l/4 of the additive genetic variance is expressed in the ratio of the between half-sib family component of variance to the total phenotypic variance (FALCONER, 1960). No heritability was detected in generation 1; the component of genetic variance among half-sib families was zero. Estimates of h2 for generation 2 and 3 were 24 percent and 38 percent, respectively. An arithmetic mean of the three estimates is 21 %, much less than’the mean of broad-sense estimates.

654 Euphytica 30 (1981)

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.L-.

PARENTS PARENTS 1973 and 1974 1973 and 1974

.I8 -

N= 98 N= 98

.I2 -

m = 11.58 m = 11.58 1 1

.08 - s = 3.95 s = 3.95

I I

o- ’ I I I I I I I I J J I I I I I I I I I I

I GENERATION 1

.I8

1972

I

I N = 266

J-, :;;::; lil,l ,!,, GENERATION 2

1973

N = 221

m = 11.04

.06 - a = 3.13

0, ’ I I I I I I I I I I I

GENERATION 3 .24 - 1974

N = 216 .I8 -

.I2 -

I = .06 III 13.88 I - s = 4.48

0 ’ I I I I I I I I I I

1.5 3.5 5.5 7.5 9.5 11.5 13.5 15.5 17.5 19.5 21.5 VASE LIFE, DAYS

Fig. 1. Distributions of vase longevity for generations 1,2, and 3 and a sample of the parents of the Davis Population.

Euphytica 30 (1981) 655

1. HARDING, T. BYRNE AND R. L. NELSON

Table 2. Between- and within-clone analyses of variance and estimates of broad-sense heritability (HZ) for VL of gerbera clones grown at Davis.

Year

1972-73

1973-74

Contrast

Between clones Within clones Between clones Within clones

Degrees of Mean freedom square

14 20.02 30 5.71 25 28.68 26 13.62

0 2* E Hz(%)

4.770 45.5

7.531 35.6

*Component of variance attributable to genotypic differences among clones.

Table 3. Components of variance and estimates of narrow-sense heritability for VL from half-sib family analyses of variance of the Davis Population.

Generation Contrast

Between families Within families Within plants

Between families Within families Within plants

10 0 0% 11 3.52 44 4.89

15 .54 24% 16 1.68 64 6.63

3 Between families 19 1.93 38% Within families 20 .89 Within plants 80 17.26

Degrees of Component of freedom variance

h2

DISCUSSION

The present results suggest that heritabilities for cut-flower vase longevity in the Davis Population of Gerbera are in the low to intermediate range. Therefore, either intense selection or selection over a large number of generations would be required to increase mean vase longevity. Mean vase longevity is between 10 days and 2 weeks, a length of time judged to be acceptable, and the trend in the population is toward increased vase- longevity, in spite of very mild selection. Consequently, selection for vase longevity has been discontinued in the Davis Population. The status of vase longevity will be evaluated at 5-generation (year) intervals.

REFERENCES

BORGHI, B. & V. BALDI, 1970. Variabilita tra cloni di gerbera allevati in diverse condizione ambientali. Sementi elette 6.

BYRNE, T. G., 1973. Spacing and leaf-removal for better gerbera production. Calif. Florist. May: 8. FALCONER, D. S., 1960. Introduction to quantitative genetics. Oliver and Boyd, Edinburgh. HARDING, J., T. BYRNE & R. L. NELSON, 1981. Estimation of heritability and response to selection for cut-

flower yield in gerbera. Euphytica 30: 3/3-322. YONG, J. DE, 1978. Dry storage and subsequent recovery of cut gerbera flowers as an aid in selections for

longevity. Scientia Horticulturae 9: 3899397.

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VASE LONGEVITY OF GERBERA

LEFFRING, L., 1973. Flower production in gerbera. I. Correlations between shoot, leaf and flower formation in seedlings. Scientia Horticulturae 1: 221-229.

MAURER, J. & W. HORN, 1967. Ergebnisse genetisch ztichterischer Untersuchungen bei Gerbera. Gartenwelt 67: 63-64.

MEET-ERING, U. VAN, 1978a. Water relations and keeping quality of cut gerbera flowers I. The cause of stem break. Scientia Horticulterae 8 : 65-74.

MEETERING, U. VAN, 1978b. Water relations and keeping quality of cut gerbera flowers II. Water balance of aging flowers. Scientia Horticulturae 9: 189-197.

MEETERING, U. VAN, 1979a. Water relations and keeping quality of cut gerbcra flowers III. Water content, permeability and dry weight of ageing petals. Scientia Horticulturae 10: 261-269.

MEETERING, U. VAN, 1979b. Water relations and keeping quality of cut gerbera flowers IV. Internal water relations of ageing petal-tissue. Scientia Horticulturae 11: 83393.

MUCENIECE, G. YA, I. D. RASALS & V. YA. DISLERS, 1978. Investigation of the inheritance of quantitative characters of gerbcra in diallel crosses. I. Productivity of plants. Genetica 14: 251-253.

MUCENIECE, G. YA. V. YA. DISLERS & I. D. RASALS, 1978. Investigation of the inheritance of quantitative characters of gerbera in diallel crosses. II. Characters of the inflorescence. Genetica 14: 779.

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