Higher Flower Production Research Articles

Response of Growth and Flowering Characters of Jasminum sambac (L.) to Modified Planting System and Pruning Schedule

Background: The study on the effect of varied plant density with different pruning levels on growth and flower yield in Jasminum sambac (L.) was carried out at the Department of Floriculture and Landscape Architecture, TNAU, Coimbatore during 2021-2022. Methods: The experiment was laid out in Factorial Randomized Block Design (FRBD) with eight treatment combinations and replicated thrice. The treatments comprised of T1 (D1P1)- Control = One plant pit-1 + one pruning year-1, T2 (D1P2) = One plant pit-1 + two prunings year-1, T3 (D2P1) = Two plants pit-1 + one pruning year-1, T4 (D2P2) = Two plants pit-1 + two prunings year-1, T5 (D3P1) = Three plants pit-1 + one pruning year-1, T6 (D3P2) = Three plants pit-1 + two prunings year-1, T7 (D4P1) = Four plants pit-1 + one pruning year-1, T8 (D4P2) = Four plants pit-1 + two prunings year-1 respectively. Pruning treatments were imposed on one year after planting of J. sambac (L.) a new clone (nine budded clone) which is prolific and high yielder. Most of the growth and yield parameters were significantly influenced by increased plant densities and pruning levels. Result: Considering the growth and flowering traits in Jasmine, the pooled data indicated that the treatment T6 (D3P2) i.e. three plants pit-1 + two prunings year-1 was found superior for growth and flowering parameters namely plant height (84.47 cm), canopy spread (0.350 m2), number of primary branches plant-1 (16.27), number of secondary branches plant-1 (36.73), number of cymes plant-1 (1989.7), number of nine budded cymes plant-1 (911.0), number of flower buds plant-1 (2875.0), flower yield plant-1 (730.3 g) and flower yield ha-1 (5071.0 kg) whereas, lowest yield (3241.5 kg/ha) was observed in T1 (D1P1) i.e. one plant pit-1 + one pruning year-1. But the parameter on days taken for first harvest of flower buds, number of flower buds cyme-1 and weight of hundred flower buds was found to be non-significant. The results might be due to increased plant density combined with alteration in pruning have enhanced not only speedy plant growth and vast canopy spread but also other yield attributing parameters such as increased number of cymes with nine buds per hectare which in turn might have resulted in higher flower production when compared to conventional planting.

Genetic diversity, population structure, and selection of breeder germplasm subsets from the USDA sweetpotato (Ipomoea batatas) collection.

Sweetpotato (Ipomoea batatas) is the sixth most important food crop and plays a critical role in maintaining food security worldwide. Support for sweetpotato improvement research in breeding and genetics programs, and maintenance of sweetpotato germplasm collections is essential for preserving food security for future generations. Germplasm collections seek to preserve phenotypic and genotypic diversity through accession characterization. However, due to its genetic complexity, high heterogeneity, polyploid genome, phenotypic plasticity, and high flower production variability, sweetpotato genetic characterization is challenging. Here, we characterize the genetic diversity and population structure of 604 accessions from the sweetpotato germplasm collection maintained by the United States Department of Agriculture (USDA), Agricultural Research Service (ARS), Plant Genetic Resources Conservation Unit (PGRCU) in Griffin, Georgia, United States. Using the genotyping-by-sequencing platform (GBSpoly) and bioinformatic pipelines (ngsComposer and GBSapp), a total of 102,870 polymorphic SNPs with hexaploid dosage calls were identified from the 604 accessions. Discriminant analysis of principal components (DAPC) and Bayesian clustering identified six unique genetic groupings across seven broad geographic regions. Genetic diversity analyses using the hexaploid data set revealed ample genetic diversity among the analyzed collection in concordance with previous analyses. Following population structure and diversity analyses, breeder germplasm subsets of 24, 48, 96, and 384 accessions were established using K-means clustering with manual selection to maintain phenotypic and genotypic diversity. The genetic characterization of the PGRCU sweetpotato germplasm collection and breeder germplasm subsets developed in this study provide the foundation for future association studies and serve as precursors toward phenotyping studies aimed at linking genotype with phenotype.

Spatial isolation impacts pollinator visitation and reproductive success of a threatened self-incompatible Mediterranean tree

Pollination service is crucial to achieve successful plant sexual reproduction and long-term population persistence. This pollination service can be affected by plant conspecific density and also by intrinsic features of individuals related to their flowering phenology and floral display. However, studies examining intrinsic and extrinsic traits on pollinator visitation and reproductive success of Mediterranean trees with limited reproduction are still scarce. We analyzed the effects of plant isolation, flowering phenology, flower weight and tree size on flower visitation probability, flowering patch visitation probability, fruit set and crop size. To this end, we intensively monitored pollinator visitation and fruit production of 67 (in 2019) and 73 (in 2020) Pyrus bourgaeana Decne trees within a threatened Mediterranean population. Our results revealed that isolated individuals received more pollinators than those on conspecific aggregations, suggesting intraspecific competition for pollinators in dense flowering neighborhoods. However, fruit set was higher in trees close to flowering conspecifics despite having fewer visits from pollinators, suggesting pollen limitation but not pollinator limitation in spatially isolated trees. Interestingly, we found increased crop sizes in spatially isolated trees which could be related to reduced intraspecific competition for resources in low-density neighborhoods (water, nutrients) and/or to higher reproductive investment (i.e. higher flower production). Overall, our results indicated pollen but not pollinator limitation in spatially isolated trees. Under this scenario of sexual reproduction mediated by pollinators, our findings stress the relevance of individuals' spatial distribution for self-incompatible trees exhibiting low individuals’ densities.

Advances in Indian Floriculture with Focus on the North-East Region

Floriculture is a remunerative and highly competitive industry. In India, floriculture is emerging as an important economic activity and foreign exchange earner. The advances in Indian floriculture sector have been brought about by the application of various technologies like vertical gardening, aeroponics, hydroponics, plasticulture, etc. The North Eastern region of the country has for long been recognized as nature’s gift to the country in view of the wealth of ornamental plants. High value flower production in protected poly and green houses are being encouraged for entrepreneurial development in the region. Current study reveals the research works and projects executed by the institutes and development centres that have led to the overall floriculture development in the region thus exploiting its potentiality.

Apple mutant trees with low chilling requirements: Proximal, genetic and DNA methylation analyses

In Arteaga, Coahuila, Mexico, different apple mutants derived from the Golden Delicious cultivar have been identified. They are characterized by their low chilling requirements (350–650 Chilling units (CU)) for breaking dormancy, and high flower production. The aim of this study was to determine the bromatological, genetic, and DNA methylation differences among ten apple mutants, and the wild-type Golden Delicious cultivar. The bromatological analyses showed that there are slight differences between some apple mutants with respect to control (Golden Delicious); in most cases, mutants were similar to each other. On the other hand, the genetic diversity among apple genotypes accessed by ISSR markers showed 57.12% of polymorphism among the 11 apple genotypes. The methylation assay showed that the Verde mutant from the Huachichil location had the highest values of DNA methylation (87.49%), even higher than the control (Golden Delicious). Furthermore, in the San Antonio of Alazanas location, the Tunal and Vigas II mutants showed the highest values of DNA methylation (62.85 and 87.61, respectively), however, the chilling requirements between these two cultivars are very different (340 and 750 CU, respectively), so it was concluded that a higher chilling requirement, is not always caused by a higher percentage of methylation. The study of these mutants may allow development of apple tree cultivars with desirable characteristics under warm winter conditions.

FLORAL BIOLOGY AND BEEKEEPING POTENTIAL OF Croton heliotropiifolius KUNTH (EUPHORBIACEAE) AT SEMI ARID REGION, BRAZIL1

ABSTRACT The aim of the present study was to determine the beekeeping potential of Croton heliotropiifolius Kunth (Euphorbiaceae) based on flowering strategy, floral characteristics, available floral resources, and the individuals frequencies and foraging activities of Apis mellifera L. on its flowers in Fazenda Ingazeira, Brazil. Each C. heliotropiifolius plant possessed inconspicuous diclinous flowers clustered into 560 ± 60 dense terminal inflorescences containing 59 ± 12 pistillate and 160 ± 26 staminate flowers. Although both types of flowers produced nectar (pistillate: 2.8 ± 0.8 μL ; staminate: 0.3 ± 0.06 μL ), A. mellifera workers mostly visited staminate flowers (98%) during the peak visitation period (08:00-11:00 h). Moreover, during the foraging period, each plant produced approximately 5.376 × 10 8 pollen grains, ensuring approximately 33 visitation cycles from a colony of A mellifera workers that picked up an average of 405 pollen grains per visit per flower. Further, C. heliotropiifolius showed an annual cornucopia flowering strategy with high flower production for five months, which is an important characteristic that ensures floral resource availability in the environment. These findings suggest that C. heliotropiifolius has a great potential for apiculture in this region.

New varieties and promising hybrids of Pelargonium grandiflorum hybridium hort. in humid subtropics of Russia

A genetic collection of the genus Pelargonium L’Herit. ex Ait., with 40 % stock represented by Pelargoniumgrandiflorum hybridium hort., is originated at the Federal Subtropical Research Centre of the Russian Academy of Sciences. The main collection varieties, including Aristo, Elegance, Candy Flowers, Hazel and Bermuda, are foreign selections attaining their best qualities under optimal soil and climatic conditions. Cultivation in humid subtropics disturbs their growth and development, at the same time as deteriorating their productivity and ornamental value. The research aimed to study the hybrid stock towards the selection of hardiest, most ornamental and long-flowering forms corresponding to a specified variety model. The variety model developed for Russian subtropic agroclimate incorporated a main set of economically valuable and adaptively significant traits. Over 30 varietal crossbreedings have been conducted to select for promising recombinants and hybrid families. A high variability of phenotypic ornamental traits has been observed in the crosses offspring. We identified 15 promising hybrids from the total morphological trait combination. Adaptive selection against stress factors has been proved effective. The most successful combinations were Hazel Ripple x Yashma, Hazel Cherry x Rozovyy Briz and A. Darling x Rozovyy Briz. A subset of elite forms (Kd-15-43, Kr-16-28 and Kc-18-22) maximising the number of significant breeding traits have further been selected towards a higher total score (≥95). K.j.-17-15, Kq-18-04 and K.ya-16-03 were recognised promising for large-flowered form selection. The Yagodnyy Tsvet variety, Kv-18-01 and K.d.-18-09 hybrids (over 35 inflorescences) have been identified as sources for high flower production. K.p-17-65, Kr-16-28 and Kc-18-22 were the hybrids with flowering period exceeding 100 days. All crosses were based on Hazel as a maternal form sourcing the trait.

Relationship of fertilizer and periodic drought on biomass allocation in greenhouse-grown sunflower

The objective was to analyze organ plasticity in biomass allocation in response to limited resources and its influence on commercial traits of potted sunflower production. Although drought dramatically increased net photosynthetic rate and water-use efficiency, total leaf area, leaf dry mass, and total dry mass with drought stress decreased at rates of 20.9, 21.8, 23.0, and 9.9%, respectively. Irrigation positively affected specific leaf area, stem mass fraction, and root mass fraction. Adversely, fertilizer had a negative effect on stem mass fraction, root mass fraction, and root/shoot ratio. Interestingly, leaf mass fraction was not affected by them. Drought and greater fertilizer amount promoted flower yield and maintained leaf mass fraction stability at the expense of stem and root production. This induced plants to produce a thin stem, poor root system, and weak lodging resistance despite high flower production. This could have significant economic consequences for commercial potted flower production.

Dynamics of leaf, flower and fruit abscission in avocado cv. Hass in Antioquia, Colombia

The amount of leaf litter produced by avocado trees cv. Hass is an important potential source of mineral resources, and quantifying its production and nature is crucial to understanding the cycling of nutrients. The main objective of this study was to quantify the production of leaf litter and fallen flowers and small fruits in avocado orchards at eight locations in three producing areas in the Department of Antioquia (west, southwest, and north). The highest leaf litter production occurred in southwest Antioquia, at Jardin (7.6 t ha-1 year-1); the east locations had similar leaf fall (4.03-3.4 t ha-1 year-1). The dry matter produced in the north was very similar in both locations. The dry matter was 2.8 t ha-1 year-1. Higher leaf litter was recorded in all locations during the driest periods. Approximately 80% of the fallen fruits had diameters less than 1 cm. The highest flower production and fall occurred in southwest Antioquia, followed by the northern region.

Graphical Assessment of Yield Stability and Adaptation of Torch Ginger (Etlingera elatior) Accessions in Two Locations

Torch ginger (Etlingera elatior) young inflorescences have been widely used in local cuisines and traditional medicine in South-East Asia. Due to the traditional use of the flowers in various Malaysian dishes, their antioxidant activity should be studied. Furthermore, it is also important to determine the crop performance for high quality flower production. Fifteen selected torch ginger accessions from MARDI germplasm collection were grown in two locations namely Jelebu, Negeri Sembilan and Jerangau, Terengganu. The aim was to estimate the genotype by environment interaction and the stability of yield performance and antioxidant activity of the accessions across two locations. Genotype plus Genotype by Environment interaction (GGE) biplot were used to determine the multivariate stability of GE interaction. The adopted technique provides a good reference for the identification of the torch ginger accession suitable for production under different ecological environments. Interactions of genotype and location effects are significant for all the traits including yield and antioxidant activity, and these may contribute towards improvement in breeding for high antioxidant production.

Improvement of Commercially Valuable Traits of Industrial Crops by Application of Carbon-based Nanomaterials

Carbon-based nanomaterials (CBNs) have great potential as a powerful tool to improve plant productivity. Here, we investigated the biological effects of graphene and carbon nanotubes (CNTs) on fiber-producing species (cotton, Gossypium hirsutum) and ornamental species (vinca, Catharanthus roseus). The exposure of seeds to CNTs or graphene led to the activation of early seed germination in Catharanthus and overall higher germination in cotton and Catharanthus seeds. The application of CBNs resulted in higher root and shoot growth of young seedlings of both tested species. Cultivation of Catharanthus plants in soil supplemented with CBNs resulted in the stimulation of plant reproductive system by inducing early flower development along with higher flower production. Catharanthus plants cultivated in CNTs or graphene supplemented soil accelerated total flower production by 37 and 58%, respectively. Additionally, CBNs reduced the toxic effects caused by NaCl. Long-term application of CBNs to crops cultivated under salt stress conditions improved the desired phenotypical traits of Catharanthus (higher flower number and leaf number) and cotton (increased fiber biomass) compared to untreated plants of both species cultivated at the same stress condition. The drought stress experiments revealed that introduction of CBNs to matured Catharanthus plant increased the plant survival with no symptoms of leaf wilting as compared to untreated Catharanthus growing in water deficit conditions.

Evaluation of the Ornamental Potential of Safflower (Carthamus tinctorius L.)

Aims: To evaluate the ornamental potential of two safflower genotypes (Carthamus tinctorius L.): ICA 73, ICA 193, grown under protected environment.
 Place and Duration of Study: Department of Agronomy of Federal Rural University of Pernambuco, between March and May 2017.
 Methodology: The methodology addressed evaluated the performance of the two genotypes, through three experiments. The first experiment was carried out in a completely randomized design, being evaluated: plant height; stem diameter; leaf dentin; spinescent margin of the leaves; number of branches; number of flower buds; spinescent margin of the bracts; flowering, and flower production. The second one was conducted in a randomized complete block design in a factorial scheme, and the following variables were evaluated: plant height; stem diameter; number of branches; number of flower buds; and flower production. Finally, the third experiment used a completely randomized design in a factorial scheme and evaluated the variables: Number of flowers; number of flower buds and post-harvest durability. The analysis of variance was performed using the F test at 5% of probability and, afterwards, the regression or comparison analysis of averages by the Tukey test at 5% of probability.
 Results: The ICA 73 access showed plants with high flower production and the ICA 193 exhibited plants with weak or moderate spinescent margin of the leaves and bracts, besides good uniformity of the anthesis of the flowers.
 Conclusion: Both accesses showed ornamental potential, demonstrating precocity, beauty and durability of the flowers. The density of one plant was the most favorable for pot plant and cut flower. The semi-open flowers harvest point was the best for maintaining the stem quality.

Deciphering the role of reproductive investment, pollination success and predispersal seed predation on reproductive output in Juniperus thurifera

ABSTRACTBackground: Plant reproductive output is determined by a complex set of factors including resource availability, pollination success and pre-dispersal predation. Disentangling the relative contribution of each factor is critical to underpin the factors determining plant fitness.Aims: To unravel the relative contributions of initial reproductive effort, pollination success and pre-dispersal seed predation to plant reproductive success in the fleshy-fruited, wind-pollinated Juniperus thurifera.Methods: We conducted an experiment including pollen addition and pesticide application on 40 female juniper trees for 20 months. Flower production was used as a proxy for resource levels.Results: Main fruit loss occurs in early stages of fruit development. Initial flower number affected fruit and seed set by (a) increasing the rate of fruit formation and the number of viable seeds within fruits and (b) modifying the incidence of low-mobile predators through a satiation effect. Pollination did not limit fruit set, although hand pollinated fruits had more viable seeds. Pre-dispersal seed predation by different arthropods was critical in defining final fruit set.Conclusions: Fruit set in J. thurifera was determined by the interaction of initial reproductive effort and pre-dispersal seed predation. Pollination was not a limiting factor in this relatively dense juniper forests during a year of high flower production.

Effects of Indole-3-Acetic Acid on the Growth Parameters of <i>Citrullus lanatus</i> (Thunberg) Matsum and Nakai

Effects of Indole-3-Acid (IAA) on Citrullus lanatus plant height, leaf number, branching and flower production were studied in order to evaluate the optimum concentrations required for growth and development. Foliar application using five different concentrations [1, 5, 10, 20 and 0 ppm IAA] was conducted twice at two weeks interval. The results suggest that as IAA concentration increases, plant height decreases with an optimum concentration of 5 ppm IAA. Mean plant height was also significantly different. More so, optimum concentration for leaf production and branching varied with varietal difference. Results obtained for number of branching suggest that 1 ppm IAA is optimum for variety A and 10 ppm is optimum for varieties B, C and D. Although flower production was poor during the study, high flower production is recorded for plants in 20 ppm IAA at 6 weeks after planting for all the varieties. This work establishes the inducing effects of different IAA concentration, which may be exploited for the commercial production of C. lanatus.Keywords: Watermelon (Citrullus lanatus), Indole-3-Acetic acid, Growth parameters, Leaf production, Plant Physiology.

Testing individual inter-annual variations in flower production by means of retrospective analysis of meristem allocation in two tree species

High inter-annual variations in flower and seed production have been frequently reported for wind-pollinated tree species. Such variations have been generally studied from a population perspective. The present study focuses on the meristematic cost of flower production in main branches of Nothofagus obliqua and N. nervosa through a retrospective analysis of flower production over 4–5 consecutive years. In both species, the percentage of flowering nodes in one year varied between 0 and 55 %. In N. obliqua, total flower production was bimodally distributed: years of high and low production were more common than years of intermediate production. Bimodality was not significant either for total flower production in N. nervosa or for each flower type separately in both species. Flower production affected branching negatively, which meant a meristematic cost. Periodicity in flower production was uneven among co-specific trees; more than two consecutive years of high flower production were rare in all trees. Inter-annual variations in the production of staminate and pistillate flowers were synchronized. In N. nervosa, the production of pistillate flowers tended to be more variable among years than the production of staminate flowers. The applied technique helps in the assessment of individual variations of flower production and contributes to understanding factors promoting seed-production variations in tree species at population scale.

Botanical Origin of Protein Sources Used by Honeybees (Apis mellifera) in an Atlantic Forest

Productive and reproductive traits of beehives are influenced by climate and food availability in the region where the bees are reared or maintained, thus honey and pollen storage, egg-laying conditions of the queen as well as comb occupation are subject to seasonal variations. The present study was conducted in the apiary of the Department of Entomology and Acarology, College of Agriculture Luiz de Queiróz, ESALQ/USP, in the municipality of Piracicaba, in an area containing fruit trees, ornamental plants and a fragment of a native forest. The objective was to identify protein sources used by honeybees (Apis mellifera) over a whole year (2010-2011) in remnants of the Atlantic forest, information that can be used in the conservation and restoration of degraded areas. For sample preparation, the acetolysis method was adopted (Eredtman 1952) and the quantitative analysis was performed by counting successive samples of 900 grains per sample which were grouped by botanical species and/or pollen types. The results show that the bees used various plant types in the area, including ruderal species, to maintain their colonies. Apis mellifera seeks food sources in all plants in the surroundings of the apiary, including herbaceous, shrubs, trees, native or introduced. Eucalyptus sp. played an important role as a food source in all seasons due to its wide availability around the apiary and its high flower production. The most frequent pollen types (greater than 10% of the sample) were Anadenanthera sp., Acacia sp, Miconia sp. and Eucalyptus sp. in winter; Philodendron sp., Mikania cordifolia, Parthenium and Eucalyptus sp. in spring; Alternanthera ficoidea, Chamissoa altissima and Eucalyptus sp. In summer; Philodendron sp., Raphanus sp. and Eucalyptus sp. in autumn.

Reproductive ecology of Ameroglossum pernambucense (Scrophulariaceae): is this ornithophilous and threatened shrub highly adapted to a naturally fragmented habitat?

Many rare plants exist in a naturally fragmented distribution and are expected to exhibit reproductive adaptations to isolation. Thus, understanding the reproduction of these plants might be important in predicting the future of artificially fragmented species. Ameroglossum pernambucense is a threatened ornithophilous shrub with naturally fragmented populations on granite outcrops in north-eastern Brazil. The current research studied two populations of A. pernambucense and determined if three reproductive features (mating system, flowering phenology and nectar dynamics) facilitate the colonisation of new areas and the gene flow among the outcrops. To verify the species’ reproductive efficiency, pollinator efficiency and pollen limitation were tested. Ameroglossum pernambucense has a mixed mating system, and pollinators increased seed production. The pollinator efficiency test revealed that hummingbirds can supply the entire pollen demand. No pollen limitation was detected. Variation in sunset time was the main factor to explain the flowering pattern of A. pernambucense. Nectar was abundantly produced after successive removals. The reproductive traits observed in A. pernambucense were interpreted as highly adapted to its fragmented condition. Phenological photoperiodic regulation may increase the flowering synchrony and chances of gene flow among outcrops in environmentally distinct microsites. The mixed mating system favours both the colonisation of isolated outcrops and allogamy. High flower production and its high energetic value may have an important role in pollinator attraction and may increase long-distance outcrossing. Our data suggest that artificially fragmented plants with reproductive features similar to those observed here might be reproductively less susceptible to fragmentation.

The carbon and nitrogen cost associated with the growth, reproductive and dormant phases of two South African semi-arid geophytic species of Gethyllis (Amaryllidaceae)

Gethyllis multifolia L.Bolus and G. villosa Thunb. (Family: Amaryllidaceae) are deciduous and bulbous geophytes that occur in the succulent Karoo biome of South Africa. Both species occupy the same natural habitat, but G. multifolia is threatened and G. villosa not. Both G. multifolia and G. villosa require seasonal bulb reserves for initial vegetative and reproductive growth. In spite of G. villosa having smaller bulbs than G. multifolia, both species produce similar flower sizes and weights. The aim of the present study was to determine the carbon and nitrogen costs of vegetative and reproductive growth during the phases of growth, senescence, reproduction and dormancy of these bulbous species. The rates, costs and efficiencies of biomass production during various growth phases of the two species were determined in a comparative experiment. The results show that in spite of a significantly smaller bulb, G. villosa produced more leaves per unit bulb mass and invested more carbon and nitrogen resources into the bulbs during senescence. G. villosa also had a higher flower production, relative to bulb weight, than did G. multifolia. These physiological responses suggest that G. villosa may be more efficient at carbon and nitrogen resource utilisation.

MORPHOLOGICAL LIMITATIONS IN FLORAL DEVELOPMENT AMONG OLIVE TREE CULTIVARS

ISHS XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Plant Physiology from Cell to Fruit Production System MORPHOLOGICAL LIMITATIONS IN FLORAL DEVELOPMENT AMONG OLIVE TREE CULTIVARS

SEXUAL, FECUNDITY, AND VIABILITY SELECTION ON FLOWER SIZE AND NUMBER IN A SEXUALLY DIMORPHIC PLANT

The evolution of sexual dimorphism will depend on how sexual, fecundity and viability selection act within each sex, with the different forms of selection potentially operating in opposing directions. We examined selection in the dioecious plant Silene latifolia using planted arrays of selection lines that differed in flower size (small vs. large). In this species, a flower size/number trade-off exists within each sex, and males produce smaller and more numerous flowers than females. Moreover, floral traits are genetically correlated with leaf physiology. Sexual selection favoring males in the small-flower line occurred via greater overlap in the timing of flower output between males from this line and females. Fecundity selection favored males with high flower production, as siring success was proportionate to pollen production. Viability selection opposed sexual selection, favoring males from the large-flower line. In females, fecundity and viability selection operated in the same direction, favoring those from the large-flower line via greater seed production and survival. These results concur with the pattern of floral sexual dimorphism. Together with previous results they suggest that the outcome of the different forms of selection will be environmentally dependent, and therefore help to explain variation among populations in sexually dimorphic traits.