GENETIC DIVERSITY AMONG Calotropis procera (Aiton) WT Aiton GENOTYPES ACCORDING TO SEED PHYSIOLOGICAL QUALITY

Abstract

-Characterizing genetic diversity based on evaluations involving germination and seed vigor, is a fundamental stage in starting the development of a cultivation system for Calotropis procera. Thus, this study aimed to estimate genetic diversity among 35 C. procera genotypes based on germination and vigor of seeds stored for 1 year. The genotypes, which originated from areas in Paraíba (Brazil), where they occur naturally, were collected and stored in March 2014. In order to evaluate the physiological potential of the seeds, two experiments were conducted between March and April 2015. The first involved a propagation test conducted in a germination chamber, while the second involved an emergence test in washed sand, performed in polyethylene trays in a screened environment under uncontrolled conditions. In both experiments, an entirely randomized design was used, with four repetitions of 25 seeds per genotype. The characteristics evaluated were germination, average daily germination, daily germination speed, the speed of germination index, the plantlet vigor index, emergence, the speed of emergence index, total length, and total dry mass. The results showed that genetic variability exists among the C. procera genotypes for variables involving germination and vigor of seeds stored for 1 year. Also, emergence, total dry plantlet mass, and germination characteristics contribute most to the genetic divergence among C. procera genotypes.

PHENOLOGY OF Calotropis procera (Ait.) W.T. Aiton ACCESSIONS BASED ON MORPHOPHYSIOLOGICAL CHARACTERISTICS

“…Germination and emergence of C. procera seeds have been studied, with promising results (OLIVEIRA-BENTO et al, 2013;OLIVEIRA-BENTO et al, 2015;ALMEIDA et al, 2017b;ALMEIDA et al, 2018), with no finding of dormancy and values that are also relatively high in the present study. These results show that C. procera has the potential to be cultivated as a xerophytic crop by using seeds directly in the production area as emergence percentage, vigor of seedlings, and pivotal root formation are essential characteristics for the establishment of seedlings in semi-arid regions of Brazil (ALMEIDA et al, 2017b;ALMEIDA et al, 2018).…”

“…Seedling vigor index (SVI) ranged from 0.12 to 2, with an overall mean of 0.37. These values are relatively high, as these seeds are from plants with occurrence natural that have a natural variability for the expression of these characteristics (ALMEIDA et al, 2017b;ALMEIDA et al, 2018).…”

“…The relative air humidity (%) and maximum, minimum, and average temperature (°C) obtained inside the greenhouse during the experiment are shown in Figure 2. The following characteristics were evaluated: seedling emergence (SE), emergence speed rate (ESR), first count (FC), and seedling vigor index (SVI) by counting the number of seedlings that emerged between the sixth and the tenth day after sowing (ALMEIDA et al, 2017b). Plant height (HEIGHT), stem diameter (SD), number of leaves (NL), average leaf length (ALL), average leaf width (ALW), leaf area (LA), and total leaf area (TLA) were obtained at 30, 60, 90, 120, 150, 180, 210, and 240 DAS.…”

Genetic Variability among Accessions of Calotropis procera Based on Agronomic Characters

“…In this context, due to the economic potential and the need for new studies on the species, research has recently been conducted on its phenology [6], seed storage [7], oil and fatty acid contents [5], metabolomic response to changes in water availability [8] and genetic diversity [9,10,11], along with a literature review on the species [2].…”

“…Almeida et al [16] started a breeding program for C. procera, with the early selection of seedlings from estimates of genetic parameters. Recently, Almeida et al [9] performed a study of genetic diversity based on seed physiological quality. However, the literature contains no genetic diversity studies of the species using phenotypic characters, and research is needed to identify divergent accessions with potential for forage production.…”