Yield and morphoanatomy of two cultivars of Brassica oleracea var. Sabellica cv. 'Darkibor' and 'Redbor' (kale) according to planting season in the School Field of the Faculty of Agricultural Sciences-UNC

Abstract

Brassica oleraceae var. saberlica, a species native to eastern Turkey, arrived in Europe and spread to almost
the entire world due to the particular flavor and nutritional content of its leaves (Tamashiro, 2017). It is
rich in calcium, iron, vitamins and has anti-cancer substances, among other properties (https://www.magyp.gob.ar/).
It is a winter leafy vegetable, with a biennial or multiannual cycle, robust, that tolerates cold temperatures
below freezing point between -7 ° C to 27 ° C. In Argentina, studies carried out in Buenos Aires reveal yield
results that oscillate between 3.1 and 6.7 tons/ha according to Logegaray (2018). It is characterized by having
an erect, unbranched and elongated stem; in which numerous simple leaves, petiolate, oblong, with curly edges
and glabrous, are inserted, which are arranged along the stem through an alternate spiral phyllotaxis. It
presents flowers grouped in a racemose inflorescence. Its fruits are siliques, needing a vernalization process
to flourish (Cartea González, 2008). The general objective of the present investigation was to compare
morphoanatomical characters and the yield of two cultivars of Brassica oleracea var. Sabellica cv. 'Darkibor'
and 'Redbor' (kale) in two planting dates in the School Field of the Faculty of Agricultural Sciences-UNC. As
specific objectives, it was proposed to characterize the two cultivars exomorphologically during their cycle,
to record different sowing times to determine optimal dates and better yields in the central region of the
Province of Córdoba and to analyze associated foliar anatomical characters. The trial was carried out in the
Experimental Field of the Faculty of Agricultural Sciences of the National University of Córdoba. The seeds
used in the trial were purchased from the company Bejo (www.bejo.es). To obtain the specimens, sowing was
carried out in germination trays. The early sowing was carried out at the end of May and the late sowing in
mid-July, and in both cases the transplant was carried out when the seedlings reached the stage of 4 true
leaves, in the months of July and September, respectively. The plots were arranged in completely randomized
blocks with three repetitions per treatment (variety per planting season, leaving 6 treatments). Each plot was
made up of three lines of 10 plants each. The plantation framework used was in borders of 0.50 m by 0.50 m,
which determines a density of 40,000 plants/hectare. Both cultivars were characterized exomorphologically in
the laboratory and in the field. For the analysis of the foliar anatomy, work was carried out in the Microscopy
laboratory of the FCA-UNC, temporary and semi-permanent histological preparations were made from cross-sections
of fresh leaves (water-glycerin 1:1 assembly), using traditional techniques and different stains ( D´Ambrogio
de Argüeso, 1986; Gil, 2013). Nikon Alphashot-2 YS2 binocular optical microscopes were used and the
corresponding photographic record was made with a 9.1 Megapixel Sony Cybershot DSC H50 and a 6 Megapixel Nikon
Cool Pix S10 camera. The measurements for the exomorphological characterization were made on the 4 central
plants of each row, whose height was measured (from the neck to the cauline apex), and 3 adult leaves per plant
inserted in the 4th or 5th node below the apex, in which the width (in the middle part of the blade) and the
leaf length (from the insertion of the petiole to the end of the blade) were measured. The leaves were harvested
considering their size (15 to 20 cm long from the leaf base to the distal end of the leaf). Subsequently, the
fresh weight was determined with a precision balance, thus obtaining the yield expressed in kg of fresh matter
per ha. The data was statistically analyzed using the InfoStat program (Di Rienzo, et al. 2020). At 60 days
from seeding, the determining photosynthetic parenchymal cells of the dorsiventral mesophyll differentiated.
The cultivar 'Darkibor' has a better behavior in early planting dates, with respect to height and foliar
development, being that 'Redbor' achieves similar values ​​in the morphoanatomical parameters analyzed for both
planting dates, determining greater plasticity when defining the same. The yield obtained in early planting
date is similar for both cultivars. All these parameters determine that early sowing dates favor the
development of the crop in both cultivars. According to the behavior and production obtained in the trials, the
cultivation of "kale" adapts to the climatic and edaphic conditions of Córdoba, making it suitable for
commercial production, obtaining the highest yields in the spring-summer season.