A 1200 m² shade house was used, covered with a white-glass mesh with a density of 52 × 25 threads/square planting on a stony soil classified as Tzek’el according to the Mayan classification or lithic Leptosol according to the World Reference Base for Soil Resources (WRBSR) [14].

Three habanero pepper varieties: Jaguar (Ja), Mayapán (Ma) and Calakmul (Ca) from creole germplasm and a hybrid named Rey Pakal (RP) from a Transnational Company, as a control were used as treatments which are being shown in Table 1.

All HP peppers are adapted to the climatic, edaphic and anthropogenic conditions prevailing in the YP, which allow the HP to guarantee its authenticity and

*INIFAP (Instituto Nacional de Investigaciones Forestales, Agrícolas, y Pecuarias).

capsaicinoid content demanded by the Denomination of Origin of the Mexican Institute of Industrial Property (IMPI).

However, different new varieties are to be required for further evaluation in order to preserve the characteristics of the HP from the YP such as shape, color, aroma, pungency and flavor.

Transplanting was carried out during the month of October and plants were irrigated every day, applying insecticides and fungicides for pests and diseases control. After transplanting, fertigation was used applying the formula of fertilization: 100-100-100 of Nitrogen (N), Phosphorus (P₂O₅) and Potassium (K₂O) respectively complemented with foliar fertilizers based on a mixture of N, P₂O₅, and K₂O and micronutrients (Fe, Mn, Zn, B, Cu and Mo) using, as a source of nutrients, the fertilizer 19-19-19 + Micronutrients ones a week.

The following variables were recorded considering six plants per replication:

Plant height (cm). Measured with a metallic field ruler from the base of the stem to the highest leaf at 15 and 45 days after transplanting (DAT). Stem diameter (mm), recorded 15 and 45 DAT, with a Vernier, in the base of the main stem, two centimeters above the ground.

Phenology. Starting at 15 DAT, the number of flower buds, opened flowers and fruits set per plant was recorded every two days until 100% of the plants showed all those phenological stages. In this way, the sampling time was twice as long as that recommended by Garruña-Hernández et al., (2012) [15] who indicate that 50% + 1 of plants is a sufficient sample to properly evaluate flowering and fructification stages in this kind of experiments.

Yield (t∙ha⁻¹). The accumulated fruit weight of 32 plants was recorded during 11 weekly pickings, with a 50 kg capacity Ohaus^® scale. The fruits were classified by quality as follows: first-class fruits with more than 6.5 g; second-class fruits weighing between 5.5 and 6.4 g and third-class fruits with less than 5.4 g [16].

The experiment was evaluated using a Randomized Complete Block Design with four replications. Each variety was established in experimental units consisting of 4 irrigation lines of 5 m long, 2.0 m apart from each other and 64 plants per plot (plants 0.3 m apart from each other) equivalent to a population density of 16,666 plants ha⁻¹. To evaluate the genetic materials, only the two central lines were harvested considering 32 plants per plot.

The data were submitted to an Analysis of Variance (ANOVA) in order to determine whether there are or not statistically significant differences among treatments considering the resulted means of the measured parameters.

In the case of significant differences among treatments a Tukey's range test was used as a complement of ANOVA as a discriminatory test capable to find specific means that are significantly different from each other.

Capsicum chinense is an annual cycle plant and it can reach 12 months depending on the agronomic management; its height is variable, ranging from 75 to 120 centimeters under greenhouse conditions [17]. In this work, highly significant statistical differences (p ≤ 0.01) were observed among varieties at both 15 and 45 DAT (Table 2).

The RP hybrid and Ja and Ma varieties registered the highest height in both evaluations with values ranging from 23.14 to 28.24 cm at 15 DAT and from 59.64 to 68.29 cm at 45 DAT being statistically similar. The Ca variety showed the lowest height with 20.38 cm at 15 DAT and 53.39 cm at 45 DAT being statistically different as compared to RP but similar to Ja and Ma.

All varieties did not reach their maximum height potential which may be due to the low light intensity that normally occurs under greenhouse conditions [18] and that additionally the register of this variable was made in a very short period of time (15 and 45 DAT) in the month of October, in a season with a low light intensity (Fall season).

It has been documented that the potential height for Ja variety ranged from 80 to 90 cm under open field conditions and up to 1.8 m under in protected agriculture systems (macro-tunnels and greenhouse) with tutoring [11]. In the case of the semi-erect Ma variety, an average height of 80 cm has been reported whilst for the Ca, with dichotomous growth habit, its height ranged from 70 to 90 cm with good canopy development [19].

No significant statistical differences were found for stem diameters among materials. There was an overall average increase of 4.24 cm from the first recorded diameter, at 15 DAT, to the second one at 45 DAT. The hybrid RP and Ma variety

Rey Pakal (RP), Calakmul (Ca), Jaguar (Ja), Mayapán (Ma). Different letters indicate highly significant statistical differences between materials by Tukey (p ≤ 0.01)

showed to be 4.48 and 4.46 mm respectively (Table 3), whilst the Ja variety had the lowest average with 3.78 mm.

No statistical differences were detected in phenology, although Ca and RP showed earlier flower buds, flowering and fruit set than Ja and Ma. Considering all genetic materials, the emission of flower buds ranged from 23.4 and 25.6 DAT, flowers opening from 38.3 to 40.5 DAT and fruit set from 42.2 to 45.3 (DAT) (Table 4). The flowering data are similar to those reported by Hernández-Pinto et al. (2020) [2], who mentioned that the Ma variety begins flowering at approximately 45 DAT. Ramirez-Meraz et al., 2018 [11] have mentioned 70 to 85 DAT for the flowering of Ja variety; or 25 and 40 DAT consistent with Table 4.

On the other hand, Garruña-Hernández et al., 2012 [15], reported that flowering of HP can be delayed at temperatures above 35˚C and even inhibited above 40˚C, which occurs during the Spring-Summer season in the state of Yucatan, Mexico. The optimum temperature for HP, in Yucatan, occurs during the Fall-Winter season, when temperatures range from 24˚C to 28˚C [20].

The analysis of variance showed highly significant differences (p ≤ 0.01) in the

*INC = Diameter Increment.

*NS = No Significant Differences. DAFB: Days to Flower Buds; DAOF: Days to Flowering; DAFRUT: Days to Fruit Set.

number of fruit set before harvesting (61 DAT). The results are shown in Figure 1; the best material was the hybrid RP with 38.5 fruits, although it does not differ statistically from Ja and Ma with 30.88 and 28 fruit set per plant, respectively. Ca was the variety with the lower number of fruit set (20.58) and it was the only variety statistically different from the hybrid RP. It can be observed (Figure 1) that RP, Ja and Ma showed better fruit set capacity, occurring from 16 to 19 days, just after detecting the first fruit set from all materials (Table 4).

According to ANOVA, highly significant differences (p ≤ 0.01) were found for both total accumulated yield (t∙ha⁻¹) and the first class yield. The RP hybrid (Control) had the higher yield with 25.32 and 23.46 t∙ha⁻¹ respectively. On the other hand, Ja yielded 22.29 and 20.11 t∙ha⁻¹ and Ma 25.17 and 22.73 t∙ha⁻¹, respectively. Ca was the variety with significantly lower yield with 13.21 and 11.71 t∙ha⁻¹ (Figure 2).

Coronado Navarro, 2017 [21], has reported yields of 31.9 t/ha for Ma variety whilst for the Ja variety very good yields (around 15 t∙ha⁻¹), have been achieved under good rainfall conditions in South-Central area of the Mexican states of Veracruz, Campeche and Chiapas, or when irrigation with medium or high technology is applied. Under field conditions, using drip irrigation and fertigation systems, yields of Ja variety can be up to 30 t∙ha⁻¹ and even higher than 43 t∙ha⁻¹ under protected closed systems. In the same production systems, local commercial HP varieties and the HP native ones have shown yields from 10.8 to 26.5 t∙ha⁻¹ and 12 - 21.7 t∙ha⁻¹ respectively [11].

In the case of Ca variety, yields of 15 t∙ha⁻¹ have been reported in open field conditions and from 25 to 29 t∙ha⁻¹ in shade house systems whilst the yields of Ma have been documented to be 30 t∙ha⁻¹ under open field conditions [19].