Index Of Self-incompatibility Research Articles

Studies on Pollination, Fruit Set and Self-Incompatibility Index in Apple Varieties under Wet Temperate Conditions of Himachal Pradesh

Studies on Pollination, Fruit Set and Self-Incompatibility Index in Apple Varieties under Wet Temperate Conditions of Himachal Pradesh

Floral biology, pollination biology, and breeding mechanisms reveal challenges to the restoration of Buchanania lanzan, a vulnerable plant species

Understanding a species' reproductive biology, which encompasses floral biology, pollination biology, and breeding system, is necessary for the restoration of endangered plant species. Buchanania lanzan is a vulnerable evergreen tree in IUCN Red Data Book due to excessive deforestation and over-exploitation. Light and scanning electron microscopy and histochemical analysis were used to study floral and pollination biology. Experiments were conducted to study floral and pollination biology, including pollen viability, stigma receptivity, and pollen-pistil interactions. Bisexual, pentamerous, complete yellowish-white flowers have an annual growth of 11 months and are arranged in terminal and axillary panicles. Anthers dehisce between 10.30 and noon, 9–10 h after anthesis. Stigmas were receptive at the time of anther dehiscence and remained receptive for two days. The flowers contain sucrose-rich nectar and emit a mild scent to attract visitors, including Musca domestica, Apis cerena indica, and black ants. None of these visitors appeared to be an effective pollinator. The results of pollination trials showed that the species outcrosses with low levels of selfing. Cross-pollinated flowers had a higher percentage of fruit sets (74.4 %) compared to self-pollinated (43.4 %) and open (3 %). The index of self-incompatibility (ISI) indicates partial self-incompatibility. Due to the probable loss of pollinators or the lack of efficient pollinators, the natural population of B. lanzan has not yet been restored. To achieve the required fruit or seed set cross-pollination facilitated by humans would be a feasible technique. Therefore, to prevent the extinction of this species, human management is required in terms of cross-pollination. As a result, the scientific knowledge produced by the current study may prove helpful in various breeding initiatives and the preservation of this medicinal plant species. Further, this knowledge forms the basis for taking measures for the conservation and management of forests.

Reproductive systems and hybridization of Lymania species (Bromeliaceae) endemic to Northeast Brazil threatened with extinction

Reproductive systems among the Bromeliaceae family are very diverse at the species level, including allogamous, autogamous, cleistogamous, agamospermic or mixed plants. Hybridization allows the creation of new genotypes with different combinations of shapes and colors to meet the ornamental plant market's demand for novelty. Knowing the reproductive strategies of the species makes it possible to obtain these new materials with ornamental potential, in addition to being essential to define better conservation strategies. Little is known about the reproductive biology of Lymania species. In addition, at least 60% of these species are on the Brazilian National List of Species Threatened with Extinction. The purpose of this study was to identify the reproductive systems, the possible interspecific hybridizations, and the possible reproductive barriers of nine Lymania species based on the germination of pollen grains and the corresponding growth of the pollen tube in the pistil by using fluorescence microscopy with ultraviolet filtering. Natural and controlled pollinations of the nine species were carried out. The reproductive strategy was defined according to the autogamy index (AI), self-incompatibility index (SII), and reproductive efficiency index (REI). All species were self-incompatible except for L. smithii, which was autogamous. Agamospermy was not observed in any of the studied species. Forty-one hybridization combinations between species were performed, resulting in a 54% success rate, with incongruity in only 12 combinations. The main incongruence phenomena identified after interspecific crosses were: poor germination of pollen grains on the stigma surface; inhibition of pollen tube growth along the style; coiling of pollen tubes along the style; pollen tubes inside the ovary but without penetration into the micropyle; and reticulate deposition of callose in the pollen tube, among others. We suggest that self-incompatibility of the species is gametophytic, preventing self-fertilization. Results showed that it is possible to perform hybridization with some species. However, morphological, genetic, and molecular studies are needed to confirm the potential of these species. Seeds generated in the different reproductive systems, as well as in the hybridizations, had germination rates above 94%. The results presented here make important contributions to the conservation of species, seed generation, and hybridization of Bromeliaceae.

Understanding reproductive biology for realization of conservation and sustainable development of Swertia thomsonii C. B. Clarke-an endemic medicinal plant of Western Himalaya

Swertia thomsonii an important medicinal plant of Himalaya is more susceptible to extinction in the scenario of anthropogenic threats and global climate change. Therefore a detailed study on reproductive biology was undertaken for its conservation and sustainable use. The present study was conducted with the aim to understand reproductive strategies, breeding behaviour and pollination ecology of this prized, endemic medicinal plant species. It is a perennial rhizomatous herb growing along an altitudinal gradient of 2550–3400 m a.s.l. The flowering commences from the month of August and continuous till September. The variation in floral traits was observed across the altitudinal gradients, which reflects its phenotypic plasticity in these characters that helps the species to get adapted in different environmental conditions. The pollen viability recorded in three study sites viz. Gulmarg (SS-I), Doodhpathri (SS-II), Pahalgam (SS-III) was 89.83 ± 3.1, 75.86 ± 5 and 84.5 ± 2.5% respectively. Stigma becomes receptive 4–5 days after anthesis and reaches its peak on 6–7th day. The presence of typical floral characteristics such as asynchronous anthesis, conspicuous nectaries, spiny exine of pollen, dichogamy, and herkogamy points towards entomophilous and outcrossing nature. Reproductive indices like outcrossing index (OCI), self-incompatibility index (SI) and selfing rate (S) as well as results of bagging experiments also revealed that the species is self as well as cross-compatible. However, fruit and seed set recorded in insect exclusion experiments confirmed its anemophilous nature and therefore species exhibits an ambophilous mode of pollination. Mixed matting is operative in the target plant species, preferring xenogamy followed by geitonogamy and autogamy. The species is pollinated by specialized pollinators which mostly belong to the Order Hymenoptera. Suitable media for in-vitro pollen germination has also been identified; the knowledge about peak stigma receptivity and pollen germination is indispensable for breeding programmes. Thus the scientific information generated in the present study may prove useful in different breeding programmes and conservation of this valuable plant species.

Assessment of the breeding system in the Algerian narrow coastal endemism Anacyclus linearilobus (Anthemideae, Asteraceae)

The breeding system of Anacyclus linearilobus, an annual and endemic species restricted to dune ecosystems of the Algerian coast were assessed through the effect of self-fertilization and intra- and inter-population artificial crosses on the probability of producing viable seeds in 20 individuals from two populations in a common garden. The breeding system was determined for each individual by the self-incompatibility index (ISI). These results were compared with those published for other species of the genus, A. clavatus, A. homogamos and A. valentinus. Results of experimental crosses showed that there was high variation in the female reproductive success between individuals of A. linearilobus, like that found in its sister species, A. valentinus. Unlike the other species in the genus that are self-incompatible, A. linearilobus showed a mixed mating system, with a majority of self-incompatible individuals, others partially self-incompatible and some self-compatible. We argue that this strategy may be related to reproductive assurance in this endemic, annual species whose effective population size has been reduced probably due to individual mating incompatibilities.

Assessment of the breeding system in the Algerian narrow coastal endemism Anacyclus linearilobus (Anthemideae, Asteraceae)

The breeding system of Anacyclus linearilobus, an annual and endemic species restricted to dune ecosystems of the Algerian coast were assessed through the effect of self-fertilization and intra- and inter-population artificial crosses on the probability of producing viable seeds in 20 individuals from two populations in a common garden. The breeding system was determined for each individual by the self-incompatibility index (ISI). These results were compared with those published for other species of the genus, A. clavatus, A. homogamos and A. valentinus. Results of experimental crosses showed that there was high variation in the female reproductive success between individuals of A. linearilobus, like that found in its sister species, A. valentinus. Unlike the other species in the genus that are self-incompatible, A. linearilobus showed a mixed mating system, with a majority of self-incompatible individuals, others partially self-incompatible and some self-compatible. We argue that this strategy may be related to reproductive assurance in this endemic, annual species whose effective population size has been reduced probably due to individual mating incompatibilities.

Reproductive Biology and Pollination Ecology of Fritillaria michailovskyi Fomin (Liliaceae), Endemic to East Anatolia (Turkey)

Fritillaria is highly endangered in their natural habitats, and these species are perennial bulbous plants with an important medicinal and ornamental value whose reproductive strategies and adaptive evolution mechanisms are still not fully clear. Therefore, the reproductive strategies of endemic species, like Fritillaria michailovskyi Fomin are important to detect the community structure and the diversity patterns of ornamental plants. The current paper on the reproductive strategy of F. michailovskyi, a rare endemic species, was carried out at the Erzincan Horticultural Research Institute, Turkey. Our results indicate that the flowering stages of F. michailovskyi may be divided into eight phases. According to pollination experiments and the pollen/ovule ratio, and the self-incompatibility index (SII) in an ex-situ population, F. michailovskyi indicated high levels of xenogamy and self-incompatibility. It was determined that the pollination of F. michailovskyi mostly depended on pollen vectors, and the effective pollinators of F. michailovskyi were Apis mellifera and Bombus terrestris. In addition, average seed number, seed germination, and average seed viability were found as 144, 46%, and 67%, respectively. The stigma receptivity, pollen grains, and pollen viability were detected as 83%, 252,000, and 95%, respectively. Our study is the first report providing a detailed explanation of the reproductive strategy of this rare endemic species, which could aid in the genetic evolution and conservation of this valuable taxa.

The nonlinear change in pollinator assemblages and self-mating syndromes ofPrimula atrodentataalong elevation gradients

AbstractThe reproductive strategies of alpine plants are often altered by environmental changes caused by changes in the spatial distribution of the gradient. However, few studies have investigated whether reproductive patterns of the same species vary with elevation. Three natural populations of Primula atrodentata, which are distributed in the eastern Himalayas and have a long flowering period, were selected along the elevation gradients in Shergyla Mountain, Tibet, China. Morph ratio investigation, floral trait measurement, pollinator observation and manipulated pollination experiments were conducted to explore the changes in self-compatibility and floral traits associated with the selfing syndrome along elevation gradients. We found that the breeding system of the S-morph is facultative outcrossing, and that of the L-morph is obligatory outcrossing. We further found that with increasing elevation, the number of pollen and ovules, anther–stigma distance, and inbreeding depression index first increased and then decreased, whereas the seeds per fruit and seed-setting rate under hand self-pollination, pollen limitation and self-incompatibility index tended to decrease first, but then increased. In addition, pollinator diversity and visiting frequency were the highest at the middle elevation (4050 population), which can better explain the nonlinear change in self-fertility with elevation. Our findings provide insights into the evolutionary pattern of self-compatibility in alpine plants along elevational gradients.

Reproductive Biology of Fritillaria aurea Schott (Liliaceae), a Rare Species Endemic to Turkey

Fritillaria aurea, unlike other Fritillaria species, is a narrowly endemic species. It has a brown checkered speckled color on each tepal and also has regular yellow intense colors on the tepals. Its large bell-shaped appearance when the flower is open is one of its most striking ornamental features. However, F. aurea plant numbers are limited in their natural habitats, and their numbers are decreasing day by day; they are even confronted with the risk of extinction owing to the damage resulting from human activities. This detailed investigation of reproductive biology plays a vital role in determining the evolutionary success and survival of F. aurea, largely in determining the effectiveness of their reproductive performance. Our results indicate that the species exhibits a very low partial dichogamy and herkogamy structure, as well as self-incompatible pollination. The flowering period ranges from March to April. Average seed viability, average seed number, and seed germination were determined as 71%, 255, and 45%, respectively. The pollen viability, pollen grains, and stigma receptivity were found as 96%, 392.000, and 85%, respectively. The pollen/ovule ratio (P/O) and self-incompatibility index (SII) in the spontaneous cross-pollination were detected as 1537 and 0, respectively. Flowers of F. aurea were visited by several insect species, mostly honeybees (Apis mellifera); Bombus sp. and Vespa sp. also played a minor role in pollination. To sum up, these results not only lay a solid foundation for further reproductive biology investigations to more broadly reveal the mechanisms of F. aurea endangerment in the future but also provide a reliable theoretical basis for hybridization breeding of parents.

Effect of Supplemental Pollination, Boron Spray and Cultivar on Fruit Quality and Quantity of Olive (Olea europaea L.)

This study was conducted during the 2020-2021 growing season at orchard of Horticulture Department, College of Agricultural Engineering Sciences, University of Sulaimani, Bakrajo, Iraqi Kurdistan Region, in order to investigate the effects of artificial pollination, boron application, and cultivar on some fruit quality and quantity of olive. Six selective pollinizers (Arbequina, Ashrasi, Hojiblanca, Picual, K18, Kaissy) in addition to self and air-pollination, two boron levels (0 and 200 mg.L-1) as well as two main cultivars (Sourani and Khadrawi) were used. Results showed that cultivars are relatively self-incompatible while cultivar, pollinizer, and boron recorded significant differences with regard to some studied parameters. Sourani Cultivar gave the highest percentage of final fruit set (1.96 %), self-incompatibility index (0.59), fruit weight (2.64 g), fruit volume (2.51cm3), oil content percentage (38.81%), soluble sugar content (185.74 μg/g DW), while the lowest fruit dropping (13.56%), and the lowest acidity value (0.46%). Besides, the highest values of boron content (10.587%) were obtained Sourani cultivar. Boron sprayed with 200 mg.L-1 achieved the highest values of all studied parameters. Moreover, Arbequina, Ashrasi, and Picual pollinizers gave the best results. The dual interactions of the factors revealed that Sourani and 200 mg.L-1 boron, the two cultivars (Sourani and Khadrawi) with Arbequina, Ashrasi, Picual and Hojiblanca pollinizers, and 200 mg.L-1 boron with Arbequina, Ashrasi, Picual and Hojiblanca pollinizers gave the best results. Additionally, triple interactions of the factors indicated that the combination of the two cultivars, 200 mg.L-1 boron and Arbequina, Ashrasi, Picual and Hojiblanca pollinizers, demonstrated the best significant results.

Breeding Systems and Pollen-Ovule Ratios inEricaSpecies (Ericaceae) of the Cape Floristic Region

Premise of research. Breeding systems dictate the potential for self-fertilization in plants and may therefore have a strong influence on evolutionary and ecological processes. Previous investigations of breeding systems in Ericaceae indicate variation in self-sterility, but studies from the megadiverse genus Erica are almost entirely lacking. Here we quantify the degree of self-sterility and autofertility in Cape Erica species, quantify pollen-ovule ratios (P/Os), and test whether these are related to each other and vary across species with bird- versus insect-pollination syndromes.Methodology. We used controlled hand-pollinations, analyses of pollen tube development, and P/Os to investigate the breeding systems of 15 taxa (comprising 13 species) of Erica in the Cape Floristic Region of South Africa, spanning most main clades across the phylogeny.Pivotal results. In all but one species, seed set from autonomous selfing was almost absent and significantly lower than that from cross-pollination, and only one species had an autofertility index that was higher than 0.2. In 12 taxa, seed set following self-pollination was significantly reduced compared with that following cross-pollination, and the index of self-incompatibility (ISI) was higher than 0.8 for 10 taxa. Following self-pollination, pollen tubes reached the ovary in all species, and for two species with very low seed set in selfed flowers, fluorescence images revealed that self-pollen tubes entered into the ovules. P/Os ranged from 68 to 320 and are therefore low for obligate outcrossing species. These ratios did not correlate with the ISI and did not vary according to whether species conformed to insect- or bird-pollination syndromes.Conclusions. This study indicates that self-sterility is frequent in Cape Erica species and either involves a late-acting mechanism of self-incompatibility or is due to early inbreeding depression. P/Os in these species are consistently low and do not reflect variation in breeding systems and pollination syndromes.

Sexual reproductive strategies ofPuya nitida(Bromeliaceae) in a Colombian paramo, a tropical high-elevation ecosystem

AbstractThe low availability of pollinators in high-elevation ecosystems can lead to flowering plants showing different adaptive responses in order to assure their reproductive success. Shifts toward autogamy and asexual reproductive rates (the reproductive assurance hypothesis) and the compensatory measures to maintain outcrossing such as flower longevity and more prolonged pistil receptivity (the increased pollination probability hypothesis) are some of these responses. Several studies have tested both hypotheses, but investigations of plants of tropical alpine environments such as paramos that support these assumptions are still scarce.Puya nitida, an endemic Colombian plant species distributed in the paramo and subparamo in the Eastern Cordillera of Cundinamarca department, was used as a case study to test its reproductive characteristics that assure its sexual reproduction. We analysed the species’ floral morphology and development, its phenological patterns and its plant mating-system. We found thatPuya nitidashowed floral characteristics that promote pollination by birds, herkogamy and dichogamy, flowers and receptive stigmas with 9 and 12 days of longevity, respectively and an index of self-incompatibility that shows that it is mostly self-incompatible. We found a synchronic phenological pattern with an annual frequency and an intermediate duration with a peak in the period of lowest rainfall. Our results suggested that longer floral development, prolonged stigma receptivity, herkogamy and dichogamy and self-incompatibility might assure reproductive success, since the cross-pollination might be favoured when few pollinators are in attendance. Overall, these reproductive mechanisms add evidence to the increased pollination probability hypothesis, specifically for a plant species of a tropical high-elevation ecosystem where pollinators are scarce.

The long spur of Impatiens macrovexilla may reflect adaptation to diurnal hawkmoth pollinators despite diversity of floral visitors

Many tropical and subtropical Impatiens species possess conspicuously long and narrow spurs and have been assigned to the butterfly pollination syndrome in investigations of floral evolution of this genus. However, this contradicts some previous studies documenting abundant hawkmoth visitors rather than butterflies. In this study, we explored the pollination ecology of Impatiens macrovexilla, a long-spurred species in Asia. We investigated a series of floral traits, tested the breeding system and contributions of different floral visitors to reproductive success, observed floral visitors and compared the spur length with the proboscis length of the nectar-collecting floral visitors. I. macrovexilla shows floral traits that cannot clearly be associated with a certain group of long-proboscid insects. Results showed that the species was visited by large nectar-collecting bees, diurnal hawkmoths, small pollen-collecting insects and rarely butterflies at different sites and in different years. Pollination treatments indicated that I. macrovexilla is self-compatible (Self-Incompatibility Index = 0.02) but completely relies on floral visitors for pollination. A treatment which excluded hawkmoths but permitted pollen-collecting insects to visit flowers revealed that diurnal hawkmoths contributed considerably to reproductive success of this species but that pollen-collecting insects acted as pollen thieves. Large bees firmly contacted anthers and stigmas when visiting flowers so probably also act as pollinators. The proboscises of large bees were shorter than half of the spur of I. macrovexilla in length, suggesting that they could only access the nectar accumulated near the mouth of the spur. However, hawkmoths can access most or all of the nectar because their proboscides match the length of the floral spur. Thus, the long nectar spur presumably reflects adaptation to diurnal hawkmoths. Using evidence from multiple lines of investigation, our study is the first to confirm the role of diurnal hawkmoths as pollinators in Impatiens.

The effect of polyamines and SICS on the compatibility, fertility and yield indices of apple cv. Golden Delicious

The most critical problems of temperate fruit trees are poor fruit set and low yield. To solve the problem, some major chemical compounds such as polyamines and SICS (self-incompatibility control substance, Mn+B) can be used. Popular polyamines including Putrescine (0.1 and 0.25 mM), both Spermine and Spermidine (0.05 and 0.25 mM), and SICS (1 and 2 mg L-1) were used alone or with cotton coverage bags to cover branches in order to investigate self-incompatibility in Malus domestica. Results showed that Spermidine (0.25 mM) led to higher yields in comparison with that of the control. SICS (2 mg L-1), also, demonstrated the highest yield compared with that of the control. At June fruit set, treatment with Spermidine (0.25 mM) led to the highest percentage of fruit set and also the highest index of self-incompatibility and percentage of final fruit set among treatments.

The Floral Biology, Breeding System and Pollination Efficiency of Schima superba Gardn. et Champ. (Theaceae)

Schima superba Gardn. et Champ. is a perennial, evergreen tree valued for its eco-protection and commercial values in China. In this study, we investigate the breeding system, reproductive ecology and pollination biology of S. superba in a seed orchard. The flowers are hermaphrodite and protogynous. The viability of the pollen is inactivated rapidly, and the stigma maintains a high receptivity within the flower lifespan. Flowers typically offer pollen and nectar to visitors. The flowers possess a typical insect pollination syndrome, and three visitors (Apis cerana cerana Fabricius, Protaetia brevitarsis Lewis, and Popillia mutans Newman) are observed on flowers during the study period. The visitation frequency per minute and capability of pollen removal and deposition of A. cerana are significantly higher than P. brevitarsis and P. mutans, although the pollinator efficiency is lower than those shown by the two beetles. Fruit set (28.27%) and seed set (6.57%) percentages resulting from open-pollination are significantly lower than those resulting from cross-pollination (fruit/seed set, 43.73%/11.66%), and the pollen limitation index (L) was 0.34, suggesting that seed production is pollen-limited in the seed orchard. The pollen/ovule ratio (P/O) and outcrossing index (OCI) values are 6686.67 and 4, respectively. The self-incompatibility index (ISI) was estimated to be 0.95. Results from hand-pollination, pollen tube growth experiments and the ISI value show that S. superba is late-acting self-incompatible. The synthetic results indicate that A. cerana is the most efficient pollinator of S. superba, and seed production is frequently limited by pollinators, fruit abortion, and pollen quality.

Using a Population Genetics Approach for a Preliminary Investigation concerning Species Boundaries inHerbertia(Iridaceae)

Premise of research. The population genetics approach is an important tool for determining boundaries in closely related plant species. Here, we adopt this approach to investigate the relationship between three species of Herbertia endemic to the Pampa biome, a complex grassland environment in southern South America.Methodology. A multianalytic approach based on population genetics was used to analyze 102 intersimple sequence repeat loci sampled in 11 populations (333 individuals) unequivocally attributed to Herbertia, aiming to test the boundaries between species. Controlled pollination experiments were performed to estimate the index of self-incompatibility (ISI), and the viability of pollen grains was estimated using the Alexander dye method, aiming to determine the breeding system in studied populations.Pivotal results. Bayesian analysis revealed three unambiguous genetic pools that corresponded to the species Herbertia darwinii (94 individuals), Herbertia pulchella (111 individuals), and Herbertia qu...

Breeding systems in Angiosperms: novel inferences from a new analytical approach

A novel analytical approach to classify breeding systems in Angiosperms combining statistical and conceptual criteria is proposed, which will allow to describe and compare available mating system data in an unified form. Four breeding system indexes (BSI) were combined: Index of Agamospermy, Index of Spontaneous Self-Pollination (ISSP), Index of Self-Fertility (ISF), and Index of Self-incompatibility. Their values, ranging from 0 to ∞, were analyzed using t tests to discriminate experimental breeding index values from 0 and 1.0. For each index, five discrete categories were described. The composite of the four BSI assigned to a species represents an integrated characterization of its reproductive system. A magnitude measure (M) describes the strength of each BSI assigned to a species. Indexes of inbreeding and outbreeding depression were also examined for each species. Published data from 1908 taxa were used to determine composite breeding systems. Frequencies of breeding index categories across the four BSI for the entire data set were determined. Non-agamospermous species dominated. Non-spontaneous self-pollinating and xenogamous species were the most frequent categories observed for ISSP and ISF indexes, respectively. The largest group of species examined was partially self-incompatible. Actual number of composite breeding systems inferred based on our analysis represents a small fraction (8.9 %) of all mathematically possible ones. Similarly, the observed combinations between results obtained from the four pollination tests and estimates of natural reproductive efficiency were only 22.1 % of all mathematically possible combinations. Within Angiosperms, there is a marked trend toward evolution of partial self-incompatibility with significant inbreeding depression.

Reproductive effort and success in Bombax ceiba L. in a tropical forest of Mizoram, Indo-Burma region of North-East India

Ecologically, the interaction between plant and pollinators is mutually beneficial for the survival and adaptability. It leads to a higher level of fitness of both interacting partners. Birds play significant roles in plant reproduction and the fitness of ecosystem in tropical forest. This study was carried out with the objective to analyze legitimate floral visitors of Bombax ceiba Linn. in tropical forests of Indo-Burma region of India in relation to pollen production and mating system. The study was performed at two different locations, namely Bethlehem Vengthlang (23°43′N latitude and 92°43′E longitude) and Tanhril (43° 37’ N latitudes and 38° 39’ E longitudes). Both study sites are located 30 km apart from each other. Analysis revealed that the pollination in B. ceiba was mostly carried out by the birds, and the flowers were visited and foraged by thirteen (13) species of birds belonging to five families of the order of Passeriformes. One species of squirrel (Funambulus sp.) was also recorded visiting the flowers of B. ceiba. Study on mating-system evaluation revealed that the B ceiba is an outcrossing tree species, requiring the services of adequate pollinators for successful pollination and reproductive fitness. However, geitonogamy was partly functional. The index of self-incompatibility (ISI) value exposed that the species is mostly self-incompatible. All the species of birds were efficient pollinators for B. ceiba in the present study sites. The fruit and seed sets following natural pollination are fairly high compared with other bird-pollinated species. High pollen-production capacities per flower and per tree along with the high visitation of bird pollinators would have promoted the maximum reproductive success in B. ceiba. This also depicts that the species does not have the problem of pollen and resource limitations in Indo-Burma region of North-East India. B. ceiba tree is often used in urban forestry, and these results can be used for a comparative study of natural and human-altered ecosystems.

Study of reproductive behaviour in low-chill apples in warmer zones of Argentina

The domesticated apple (Malus×domestica Borkh.) shows abnormalities in its flowering biology when it is growing in mild-winter areas. Hence, the flowering phenology and the mating system (e.g., open-, cross- and self-pollination, apomixis and parthenocarpy) of Caricia, Eva, and Princesa apple cultivars were studied in three consecutive growing seasons. The flowering period ranged between August and October with wide variation between years, especially in relation to the overlapping of the full-bloom periods. Fruit set by selfing was significant, reaching a mean value of 20% with a minimum of 4.5% and a maximum of 43.7%, depending on the growing season and the cultivar. The self-incompatibility index showed significant changes between years in Eva and Princesa but not in Caricia. Fruit and seed set were significantly greater in cross- and open-pollination treatments than by self-pollination, apomixis or parthenocarpy. Those variables were affected by a growing season×treatment interaction. The results indicated that Caricia, Eva, and Princesa apples show partial to full self-incompatibility, depending strongly on the growing season. However, better fruit and seed set rates are obtained by cross-fertilization.

Reproductive success and compatibility among accessions of <i>Jatropha curcas</i> in Indonesia

Large scale exploitation of Jatropha curcas for biofuelproduction is restrained by low productivity henceeconomically not protable. One of the main constraintsis due to limited number of female owers in aninorescence which eventually develop into fruits thatbear seed. Investigation on oral biology andreproductive potential of the species had been carriedout, but seems to vary among sites. The research wasconducted to study reproductive success and thecompatibility among Indonesian Jatropha accessions.The research was set up in two experiments. The rstexperiment was conducted at the Jatropha seedorchard, Pakuwon, Sukabumi, West Java from April toJuly 2007 using four-year- old trees of accessions fromLampung, Banten, West Java, and Central Java. Thesecond experiment was conducted at LeuwikopoExperimental Station of Bogor Agricultural Universityfrom April to July 2008 using one-year-old trees ofaccessions from Lampung, Bengkulu, Palembang, andKediri. Flowers were obtained from controlled self andcross-pollinated as well as left for open-pollination. Theresult showed that reproductive success varied amongaccessions; the greatest success was 0.73 obtainedfrom aWest Java accession and the least was 0.53 fromBanten accession. The Jatropha accessions werecategorized as partially self-incompatible as indicatedby index of self-incompatibility (ISI) that ranged 0.93-0.99. Banten accession produced highly viable andvigorous seeds regardless of pollination methods;accessions of Central Java produced higher viabilityseeds when cross-pollinated within accession, whereasthose from West Java and Lampung produced higherviability seeds when self-pollinated.Keywords: accessions, Jatropha curcas, selfpollination,self-incompatibility, seedviability