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Manuscript: Exploring South-East Brazilian Wild Capsicum

1 Associazione PepperFriends (claudiodalzovo@pepperfriends.com)


The search for wild Capsicum in their habitat revealed interesting aspects.

Species differentiation.
Few species are clearly differentiated on the basis of their morphology and habitat.
C.hunzikerianum is very different from all the other species in its habit and habitat, its leaves, flowers, fruits and lack of pubescence.
C.friburgense is unique for the shape and color of its corolla.
C.dusenii is well-differentiated for its flower, the dense pubescence, the calyx with 10 teeth of the same length and above all for the lack of pungency.
C.villosum is immediately recognizable for the very dense pubescence.

The population of C.pereirae which grows at Ibitipoca is well-differentiated for its habitat, the flower pendulous not geniculate, the leaves coriaceus.
Capsicum sp.9 of Caraça is unique for the linear leaves and the size of its flowers.
This accession has no name yet; in some features it is similar to Capsicum mirabile Mart. described in Flora Brasiliensis [1], especially for the leaf shape, but it differs for other traits, such as pubescence and growing area.
Possibly it represents a species not yet classified, also in consideration of its geographical isolation from other Capsicum populations.

Uncertainties in the classification (Groups of species or populations with classification issues).
Some populations found in different sites and classified as distinct species show minor differences.
It is thus possible that these populations are actually ecotypes belonging to the same species with differences caused by environmental conditions.
In other cases there are significant differences between populations assigned to the same species; we could observe a great variability in morphological traits such as corolla color and shape, number, length and shape of calyx teeth.

These traits vary even within the same population, especially when it consists of many individuals (e.g. C.recurvatum at Park Botelho) or when populations grow in different climatic and soil conditions.
This peculiarity makes difficult in many cases to establish clear boundaries and determine to which species belongs a certain population.
Notwithstanding it’s possibile to identify some groups with common features.

The group of C.cornutum includes populations characterized by the calyx with 10 teeth (sometimes 5 inconspicuous), but different corolla colors, with green or yellow spots (Serra do Mar) or completely white (accessions LBB1547 at Cunha and the plant (accession 461-462, 1986) on the road Cunha-Paraty close to the state limit SP-RJ).
The accessione LBB1546 (at lower altitude on the same road) has corolla with golden spots; fruits may occasionally show only 5 teeth.
Corolla colors of accession LBB1542 at Casagrande are unknown.

This is a heterogenous group which could include several species.
It is curious that populations growing close each other in the area between Cunha and Paraty share several characteristics, but differs in other morphological traits; populations with white corolla and 5 teeth, white corolla and 10 teeth, golden-spotted corolla and 10 teeth were found.
The pubescence is also variable.

Morphological differences with C.dusenii are clear, especially the presence/absence of pungency, even if some botanists consider C.cornutum synonymous of C.dusenii.
C.dusenii also differs from other Capsicum because it only seems to set up flowers and fruits very early in spring (so it was not possible to find open flowers)..

Another group includes populations with 5 teeth in the calyx, corolla with greenish/yellowish spots in the throat and purplish red in the lobes, scarce pubescence; C.buforum and various populations identified as Capsicum sp.6 belong to this group.
Some experts think that these populations match C.mirabile described in Flora Brasiliensis [1], but the recent literature contains conflicting indications on the name to use, C.buforum or C.mirabile.
Despite the common features, there are obvious differences and a great variability, even in the same population.

  • The population of Lefévre and Campos do Jordão fit the definition of C.buforum given by Hunziker in 1969 [2] and grow very close to the original site.
  • The population of Orgãos is very similar to the previous one and well recognizable from others, but has some peculiarity, especially in the intensity of corolla and buds colors.
  • In the population of Piquete the purplish red color in the corolla fills almost entirely the lobes and is variable from plant to plant; it’s often also well visibile on the back of the petals.
  • The population of Ibitipoca also shows a great variability in the intensity of the purplish red component of the corolla and in the teeth length; at first sight we thought that C.sp.6 shared the same area with a population of C.schottianum.

The group of C.recurvatum spread in the area at South and East of São Paulo (Parque Botelho, Morretes, Paranapiacaba) presents great variability in the shape, orientation and length of the teeth; sometimes they are well-formed and curved backwards, in other cases reduced or almost absent, even in plants growing side by side.
Corolla has greenish/yellowish or pure green spots.

The group of C.schottianum includes populations with calyx toothless and corolla with greenish/yellowish spots, sometimes with more or less obvious purplish red component which may be absent or present even in flowers from the same plant at different times.
Calyx has 5 nervatures which sometimes originate small teeth.
The difference between C.schottianum with small teeth and C.recurvatum with reduced teeth is minimal; some populations, for example those at Paranapiacaba (in the Reserve and near the railway station) could be included interchangeably in both groups.

C.campylopodium could also be part of the C.schottianum group.
The distinguishing characters of this species are corolla with yellow spots, androecium heterodynamous with 3 short stamens and 2 long stamens, fruit compressed laterally, toothless calyx.
These differences are quite vague because one or more of the same characteristics may be detected even on C.schottianum or other species.

Stamens of different length were documented in Capsicum lanceolatum (Greenm.) Morton & Standley, C.pereirae and C. sp.9 of Caraça, but it’s a temporary phenomenon caused by a different speed of maturation of the anthers after the flowering; it’s possibile that this phenomenon occurs even on C.schottianum, although not observed.
The lateral compression of the fruits is caused by a peculiar arrangement of a group of 4 seeds, 2 per locule; the same peculiarity is frequent in C.schottianum too, but not on all the fruits of the same plant.
It is interesting to highlight that the areas where C.campylopodium was found in the past are almost always overlapped to those of C.schottianum and that, despite our extensive exploration, we never found plants identifiable certainly as this species, even if it should be widespread.

A single small plant of C.villosum var muticum , morphologically very similar to C.villosum (especially for the dense pubescence) was found; however it showed two important differences, the lack of teeth in the calyx (hence the name muticum of the variety) and above all the corolla with greenish/yellowish spots, but purplish red component absent or very limited.
The peculiar color could be due to the growing conditions, but it should be noted that C.villosum presents a great homogeneity in the corolla colors, even in populations growing far apart each other; the purplish red spots are always present and intense.
Purplish red spots are described in literature for C.villosum var. muticum [13], so the plant we found could be an exception; further investigations are needed.

Two populations of C.pereirae in two far apart areas and different habitat share common features such as pendulous and not geniculate flower and toothless calyx.

  • At Ibitipoca the species grows in two distinct sites, but shows homogeneous characteristics.
  • The habitat (“gruta humida”) is the most peculiar among all those visited, a kind of oasis in the middle of an arid Park, with very scarce natural light and high humidity.
  • The populations of Castelo live in a very different habitat, the typical Mata Atlantica.

A careful observation of the few photographs in the paper where the species was at first described [8] highlights that the corolla colors and other features are variable; in one photograph a flower shows different colors and shape and in the background there is another flower clearly geniculate.

C.caatingae is a case unto itself.
When we saw this species, it was still classified as C.parvifolium, but when we carefully observed its characteristics, it soon became clear that it didn’t correspond to C.parvifolium described in Flora brasiliensis [1], especially for the absence of teeth in the calyx.
We also noticed a feature yet not highlighted in literature, the annular constriction, more evident in mature fruits.

The classification was clarified in a paper published shortly after [12]; the plants cultivated at Viçosa are just a new species, C.caatingae.
The paper accurately describes also the “true” C.parvifolium and a third, new species of arid biomes characterized by very long teeth in the calyx, trichomes of various type and absence of pungency: Capsicum longidentatum Agra & Barboza.

Features of fruits and seeds.
The features of fruits and seeds suggest that the main dispersors are small mammals which gather the fruits fallen on the ground.
The higher pungency in the immature fruits could encourage the consumption of only ripe fruits and deter any attempts to collect immature ones.
Tough seeds could be an adaptation to pass without damage through the digestive system of small mammals and rodents.
However, there aren’t studies on fruits predation and seeds dispersion for these species.
It is not even clear what are the pollinators; insects in proximity of the flowers were never observed.

Distribution of species and risk of extinction.
Some species are widespread (C.schottianum, C.villosum).
Others live in small areas, but with large populations; the population of C.recurvatum in the Parque Botelho extends along a dirt road for over 20 km.

However, there are species with extremely small populations (in the visited sites), sometimes only a few individuals in a narrow area.
We found a dozen plants of C.hunzikerianum, only half of which were adult.
Approximately 20 plants of C.friburgense are present in an area less than 1000 m2 wide; only one of the three populations originally described at different altitudes is still present and the plants found near the road were recently cut and re-sprouted.
The site seems to be used as pasture for cows.

Only a single plant which could be C.friburgense was found (during the fourth trip) in another site where a population was present in 1986; however the plant had no flowers and only few fruits with 5 small teeth, so identification is uncertain; in the same place also plants of C.schottianum were present.
Only a few plants of C.pereirae are present at Ibitipoca, fortunately in a well-preserved habitat.
The species seems to have disappeared from one of its original sites, the area near Castelo, subject to a rapid development and intensification of agricolture.

C.villosum var. muticum was not found in one of its historical sites, only a single small plant was found nearby in a quite risky situation.
Only a single plant (without flowers and fruits) was found along the road Resende-Caxambù, where C.villosum was common in 1999.
No wild Capsicum was found along the Estrada do Sertão near Bananal and the current situation doesn’t seem suitable for their growth.

The situation of Capsicum sp.9 at Caraça is critical; we found out only one single adult plant and a few seedlings in a cut underbrush; other populations might grow in other sites, inside the Park, but so far there are no reports of other findings.
Single adults plants can often be found at roadside, just outside the area cut for maintenance, but the small “mudas” are steadily cut.

The destruction of the habitat is not the only risk; another critical factor is the difficulty of reproduction in some populations.
In some cases very old isolated plants were found, without “mudas” nearby.
An emblematic case is the plant of C.cornutum with white corolla found along the road Cunha-Paraty in 2011; the plant grows in the exact place where a single plant with the same features was found in 1986 and looks old enough to be the same plant; there aren’t other Capsicum plants for kilometers all around.

During the fourth trip a different situation was observed; the old plant was cutted and resprouted; another young plant was found nearby.
Even if there may be undetected populations or interesting areas still unexplored, some species could disappear in a short time; it seems necessary to protect some populations at risk, even growing them ex-situ.

Exploration of sites not mentioned in literature led in many cases to find out populations or single plants, but always belonging to the most common species (C.villosum and C.schottianum).
A systematic exploration of promising areas could lead to find out new populations or perhaps new species; the recent classification of well-differentiated species (C.pereirae, C.friburgense, C.hunzikerianum [8]) demonstrates that there is still much to discover.
Up to now populations were found especially aong roads and tracks (with the exception of C.pereirae and C.hunzikerianum).
Determining the habitat of these species in the pristine Mata Atlantica could help to find new populations.

Classification criteria.
Our experience highlights the need to develop criteria to more precisely determine different species.
It would be necessary to define which morphological criteria are definitely relevant to differentiate the species as a great variability on the corolla colors and leaves shape can be observed, even in the same species or populations, while the presence and number of teeth and the pubescence seems to be relatively constant.

Field observations suggest that corolla colors and its shape (more or less open), the size of calyx teeth and the size and proportions of the leaves are strongly depending on the exposure to the sun and on the growing conditions and may vary from individual to individual in the same population; thus these characters aren’t always useful parameters to differentiate these species.
Growing these species in a controlled environment could reduce environmental influence.

Presumably DNA-based assessment might solve many doubts.
Interspecific breeding could also give information on possible crossing and species differentiation.
In literature only one attempt to use South East Brazilian wild Capsicum in interspecific crosses has been documented [7], but not with other species from the same area.
In nature interspecific crosses between these species are not known and we never found plants with intermediate features in sites where populations of different species grow side by side, e.g. C.villosum and C.schottianum.

The possibility of using these wild species as a source of useful genes for cultivated species should be evaluated, in order to add resistance to diseases and adverse weather conditions.
First step is the determination of potentially useful genetic traits.
It is possible that these species are particularly resistant.
For example, a simple experiment carried out by Claudio Dal Zovo in Italy on C.flexuosum (plants from seeds distributed by the USDA genebank) demontrate without any doubts that this species is frost resistant.
Plants survived two winters outdoor (in pots), with temperatures down to -12°C.

The investigation of the possibile use in breeding should consider that all these wild species are 26n (except C.flexuosum) and therefore are not easily hybridizable with the cultivated species.
Tong and Bosland reported [7] an attempt to hybridize C.buforum with 9 cultivated and wild species (C.praetermissum, Capsicum cardenasii Heiser &Smith, Capsicum eximium Hunz., C.lanceolatum, Capsicum tovarii Eshbaugh, Smith & Nickrent).

The results of interspecific hybridizations showed varying degrees of compatibility, but no viable hybrid seeds were produced.
Gábor Csilléry, one of the authors, deeply studied interspecific crosses using wild species [4], but none from South-East Brazil; however, his experience could be very useful.
A good starting point to investigate interspecific crosses could be C.flexuosum x C.baccatum L., because C.flexuosum is a 24n species and should be quite similar to C.baccatum .

In cooperation with Brazilian Institutions and in accordance with the International Conventions on Biodiversity Conservation, these species should be grown and studied, before they disappear!