Ethics statement
The research conducted herein did not involve measurements with humans or animals.
The study site is not considered a protected area. No protected or endangered or species
were used in the course of carrying out this study, however, some special permissions
need to be get at the ProcuradurÃa Federal de Protección al Ambiente (PROFEPA) at
La Paz, Baja California Sur, México. Capsicum annuum used in the present study is not considered an endangered species and their use therefore
had negligible effects on broader ecosystem functioning.
Sampling populations
Three populations (Figure 1) were located in three sites along Baja California Sur (B.C.S.), Mexico to identify
wild C. annuum ecotypes. The three sample wild populations were selected based on information provided
by local inhabitants in each municipality of Baja California Sur. This data of wild
Capsicum plants was assessed in extensive field trips and respective interviews with communities
and farmers located in wild areas, i.e. in Mulegé municipality, the population of
Santa Lucia mountain with more abundance in wild Capsicum plants is the area called Los Gatos (The Cats) and surroundings. The sample populations
were positioned geographically using a global positioning system (Garmin GPS Map 60Cx).
One population was situated in the first site, which was in the municipality of Mulegé
(Los Gatos Ranch) near the limit area of biosphere reserve El Vizcaino, B.C.S., México.
The second population was located in a second site in the municipality of La Paz (San
Bartolo town) and the third population of the third site was located in the municipality
of Los Cabos (Santiago town) both near the area limit of the biosphere reserve La
Laguna, B.C.S., México. Los Gatos is located in a semiarid zone of Baja California
Sur, northwest of Mexico (27°01?46? N, 112°26?59? W), 680 meter above sea level (masl).
Los Gatos is a wild Capsicum population surrounded by some cattle ranches, located in a small range just behind
Santa RosalÃa, B.C.S., at Santa Lucia Mountain, which joins the Sierra of Guadalupe
to the south. This wild Capsicum population is located around the limits of El Vizcaino biosphere reserve, close to
the highest hill called La Bandera. Below the Pacific slopes of the mid-peninsular
range, the Central Desert stretches from 30°N to 26°N and encompasses the Vizcaino
Desert and, to the south of the Madgalena Plain. The soils of this population are
shallow, of recent formation and high rate of erosion, characterized as lithosol soils,
with low organic matter, have no structure to be composed of unconsolidated material
with high sand content. Are set on hills and mountain areas, where the type of vegetation
is found of sarcocaule scrub. Are coarse textured and are associated with eutric regosols.
San Bartolo is located in a subtropical zone of Baja California Sur, northwest of
Mexico (23°45?43.9? N, 109°58?30.6? W), 526 masl. The wild Capsicum population of San Bartolo is located around the limits of La Laguna biosphere reserve,
near Sierra of La Laguna lies below La Paz in the Cape Region. The range is called
La Laguna after a mountain meadow that, according to natives, was once a lake. This
wild Capsicum population is close to Arroyo (Dry River) of San Bartolo that it is large. This population
is located in the east face of La Laguna Mountain, with high precipitation, with deep
canyons and luxuriant growth found on many of these gradual eastern slopes. The soils
of this population are predominantly eutric cambisol, a weakly developed mineral soils
in unconsolidated materials, soil management affects moisture-holding capacity, the
highest moisture contents is found in undisturbed soils, which are related to low
organic matter contents, medium to low porosity and low values of structural stability.
Santiago is located in a subtropical zone of Baja California Sur, northwest of Mexico
(23°23?55.5? N, 109°40?45.6? W), 226 masl. The wild Capsicum population of San Santiago is located around the limits of La Laguna biosphere reserve,
near Sierra de La Laguna lies below La Paz in the Cape Region. The range is called
La Laguna after a mountain meadow that, according to natives, was once a lake. This
wild Capsicum population of Santiago is close to Arroyo (Dry River) of San Bernardo and Arroyo
of San Dionisio, both are large. This population is located in the southeast face
of La Laguna Mountain, is steep, with deep canyons and luxuriant growth found on many
of the more gradual eastern slopes. The soils of this population are dominated by
eutric cambisol that with natural vegetation had the highest moisture-holding capacity,
the highest rates of infiltration are found for natural vegetation soils, structural
profile and porous system are more stable in unchanged soils. Figures 2, 3 and 4 shows the environmental conditions such maximum, minimum and average temperature
(°C), precipitation (mm), evapotranspiration (mm), solar radiation (w m?2) and relative humidity (%) of the three sample populations in a range of 73 years
from 1939 to 2013 along January to December (monthly average). The meteorological
observations were obtained during the study from an automated weather stations located
at the study areas which are property of the National Institute of Forestry, Agricultural
and Livestock Research (INIFAP) and from the National Weather Service (SMN) both institutions
of the Secretary of Agriculture, Livestock, Rural Development, Fisheries and Food
(SAGARPA) with coverture in all regions of Mexico.
Figure 1. Localization of wild Capsicum ecotypes collected in three populations near two biosphere reserves in Mexico.
Figure 2. Maximum, minimum and mean temperature of three populations, Los Gatos (A), San Bartolo (B) and Santiago (C) of wild Capsicum ecotypes collected near two biosphere reserves in Mexico.
Figure 3. Precipitation and evapotranspiration of three populations, Los Gatos (A), San Bartolo (B) and Santiago (C) of wild Capsicum ecotypes collected near two biosphere reserves in Mexico.
Figure 4. Solar radiation and relative humidity of three populations, Los Gatos (A), San Bartolo (B) and Santiago (C) of wild Capsicum ecotypes collected near two biosphere reserves in Mexico.
Vegetation associated to wild Capsicum (in-situ)
In each sample population, two rectangles of 50?×?20 m (1000 m2) were traced and each Capsicum plant were counted and identified in each rectangle. One square of 4?×?4 m (16 m2) was traced around each Capsicum plant found and the vegetation associated was identified the family, common and scientific
names.
Morphometric traits measured in plants (in-situ)
In each sample population, five wild Capsicum plants were selected completely randomized and the height (cm), plant coverage (m2), main stem diameter (mm), as well as the height of the beginning of canopy (cm)
were measured. We collected only five plants of each sample population since the ProcuradurÃa
Federal of Protección to the Ambiente (PROFEPA) authorized only the collection of
a limited number of wild Capsicum plants and fruits. This species is perennial, however annual growth change yearly,
thus this first study will be important for providing the baseline for future growth
studies of this plant species. Plant coverage, plant height and height of beginning
of canopy were measured using a metric tape of 5Â m and main stem diameter was measured
using a digital caliper (General No 143, General Tools®, Manufacturing Co., Inc.,
New York, USA) at a plant height of 0.20, 0.40 and 0.60Â m and the result was averaged.
The growth types of all Capsicum plants found in each sample population were recorded. The growth type was identified
as two types, as erect (shrub type) or climbing (vine type).
Plants and fruits collection
Previously to realizing the collection, a specific permission needs to be granted
by PROFEPA in La Paz, Mexico in order to collect wild Capsicum plants and fruits. These plants at present not considered endangered or protected
species. However, for future plants and fruits collection of Capsicum and other species in the sample populations near both biosphere reserves will be
sampled after attaining appropriate permissions contacting to Mr. Leonel Valerio Castro
Santana, Federal Officer of PROFEPA in Baja California Sur. In each sample population,
the five plants of wild Capsicum selected were collected and completely randomized (including roots). These plants
were used for morphometric measurements. Each plant was considered as a replication.
The collected plants were introduced in paper bags, labelled, stored in cardboard
containers and moved to the laboratory of plant physiology at Centro de Investigaciones
Biológicas del Noroeste, S.C. (CIBNOR®) at La Paz, México. Before the collection of
each plant, the total fruits per plant were harvested and placed in paper bags, labelled
and stored in a cardboard container and moved to the laboratory. At the same time,
400 mature fruits from different plants (without collecting) at each sample population
were collected, introduced in paper bags, labelled and moved to the laboratory. Each
group of 100 fruits was considered as one replication. We collected 400 mature fruits
because PROFEPA authorized only the collection of this quantity of wild Capsicum fruits based on the criteria of the normativity for wild vegetation in Mexico considering
criteria for conservation and management of resources.
Morphometric traits measured in collected plants and fruits (laboratory)
In the laboratory, the five wild Capsicum plants collected were separated into roots, leaves and stems and the following variables
were measured:
Leaf area, leaf length, average and maximum width of leaf
Leaf area (cm2), leaf length (cm), average (cm) and maximum (cm) width of leaf of each collected
plant of each sample population that was collected was measured with a Li-Cor portable
leaf area meter (Li-Cor®, modelo-Li-3000A, series Pam 1701, Li-Cor® Lincoln, Nebraska,
USA).
Leaves, roots and stems dry weights
All leaves, roots and stems dry weights from each plant collected in each sample population
were recorded. The leaves, roots and stems were placed in a pre-heated oven (Shel-Lab®,
model Fx-5, serie-1000203) at 80°C, until constant weight, in order to obtain leaves
(g), roots (g) and stems (g) dry weights which were obtained using a conventional
scale (Ohaus®, model CT600-S, USA, series 18939).
In the laboratory, the 400 fruits harvested from each sample population and those
fruits collected in-situ were separated into peduncle, seeds and fruit pulp and the following variables were
measured:
Number of fruits per plant, peduncle length and fruit average fresh and dry weights
Each fruit collected from each collected plant were counted and recorded. The peduncle
of each fruit was separated from the fruit and the length (cm) was recorded using
a digital caliper (General No 143, General Tools®, Manufacturing Co., Inc., New York,
USA.). Average fresh weight of fruit (g) was determined using a conventional scale
(Ohaus®, model CT600-S, USA, series 18939) and average dry weight of fruit (g) were
obtained when each group of fruits from each plant were placed in a pre-heated oven
(Shel-Lab®, model Fx-5, serie-1000203) at 80°C, until constant weight.
Number of seeds per fruit, fruit length and width
The 400 mature fruits collected from each sample population were used to determine
the number of seeds per fruit, length (mm) and width (mm) of fruit which were measured
using a digital caliper (General No 143, General Tools®, Manufacturing Co., Inc.,
New York, USA.).
100 fruits dry weight, seeds and pulp dry weight of 100 fruits, 1000 seeds dry weight
and pulp/seeds ratio
The 400 mature fruits collected from each sample population were separated in four
groups of 100 fruits and fruits dry weight (g), seeds (g) and pulp (g) dry weight,
pulp/seeds ratio and 1000 seeds dry weight (g) were measured. The dry weight were
obtained when the fruits or seeds were introduced in a pre-heated oven (Shel-Lab®,
model Fx-5, serie-1000203) at 80°C, until constant weight.
Mineral content of roots, stems and leaves
The mineral content in roots, stems and leaves is an important variable that influences
the plant response under different environmental conditions. All roots, leaves and
stems after being separated from the main plant were rinsed by dipping three times
for a few seconds in distilled-deionised water before measuring dry weights. Separately
roots, leaves and stems dried tissue were finely ground in a blender (Braun® 4–041
Model KSM-2) for mineral analysis. The Na, Ca, Mg, Mn, Fe, Cu, Zn, and K (all in g
kg?1 dry-weight) content was determined by atomic absorption spectrophotometer (Shimadzu
AA–660, Shimadzu®, Kyoto, Japan) after digestion with H2SO4, HNO3, and HClO4. Phosphorous (g kg?1 dry-weight) was estimated colorimetrically as phosphomolybdate blue complex method
at 660Â nm from the same extract.
Statistical analysis
Bartlett’s test was performed on the data to test the homogeneity of variance. Data
were analyzed using a fit model using a standard least squares means personality function
and univariate and multivariate analysis of variance (ANOVA and MANOVA). All plants
and fruits variables were analyzed for one way of classification, being sample population
the study factor. The least significant differences were calculated using Tukey’s
HSD test (p???0.05) when the analysis of variance was significative. As a wild population, the
coefficient of variation for each variable was considered. In all cases, differences
among means were considered significant at p???0.05. Single and multiple Pearson’s correlation coefficients (r) at 95% confidence limits for independent variables (environmental conditions) and
dependent variables measured in plants, fruits and seeds was determined. All analyses
were done with Statistica software program v. 10.0 for Windows.
Availability of supporting data
The authors confirm that all data underlying the findings are fully available without
restriction. All the relevant data that is needed to replicate this study and to draw
the conclusions for this study is within the paper.