Genetic Variability among Accessions of Calotropis procera Based on Agronomic Characters

This study evaluated the genetic diversity among 70 accessions of Calotropis procera based on agronomic characters. Seeds of C. procera were collected in the Northeast region of Brazil. The experiment was conducted in a greenhouse in Campina Grande, Paraíba State, between January and September 2016. The plants were grown for 240 days after sowing in plastic pots filled with soil. Data regarding 23 characteristics were recorded and analysed statistically (ANOVA and cluster analyses. The ANOVA has detected differences between accessions for all the characteristics indicating that all 23 agronomic characters were polymorphic. The coefficient of genetic variation ranged from 3.43% for average leaf length to 96.09% for the beginning of flowering, but were generally low (CVg < 15%) and moderate for leaf mass related parameters (CVg: 20.81-35.08). Heritability varied from 45.95 for seedling vigor index to 98.64 for total leaf mass. Globally, the high heritabilities of the various agronomic characters were explanatory of the low coefficients of genetic variation recorded. A total of 9 accessions over the 70 were found promising for use in the C. procera breeding program for final emergence percentage, speed of emergence index, beginning of flowering and number of flowers per inflorescence. They have also, presented forage potential (average total fresh mass: 1115.52 g and average leaf dry mass: 19.26 g), and should be preserved for posterity.