Deficiência de nutrientes em uma cultivar e estimativa de parâmetros genéticos em populações segregantes de manjericão

Abstract

Basil (Ocimum basilicum L.) is a medicinal, aromatic and condiment plant widely cultivated around the world. It exhibits considerable phenotypic variability, manifested in various traits such as plant size, leaf and flower coloration, essential oil (EO) composition, and antioxidant activity. This variability comes from the interaction between genetic and environmental factors such as cultivation methods, fertilization, and light conditions. The interaction between genotype and environment is complex and determines the phenotypic variability observed in basil populations. In Chapter 1, the influence of macronutrient and micronutrient deficiencies on the growth of an Italian Large Leaf basil cultivar was evaluated. Nutrient deficiencies significantly affected plant growth, with nitrogen and phosphorus deficiencies causing marked reductions in aerial dry mass (-N = -96% and -P = -99%), root dry mass (-N = -94% and -P = -96%), plant height (-N = -72% and -P = -93%), and leaf area (-N = -78% and -P = -97%). Visual symptoms typical of nutritional deficiencies were observed, such as leaf yellowing in nitrogen deficiency, tip curling in calcium deficiency, and leaf edge burning in potassium deficiency. It was concluded that basil is sensitive to nutritional deficiencies, highlighting the importance of adequate nutrient balance for favorable growth. In Chapter 2, genetic parameters were estimated in a segregating population derived from triple hybrid basil (Anise x Cinnamon) x Italian Large Leaf. The F2 population showed significant genetic variability, with high (>20%) coefficients of genetic variation (CVg) and phenotypic variation (CVf). High broad-sense heritability (ha 2) was observed for dry mass (ha 2 = 82.0%), plant height (ha 2 = 80.0%), canopy diameter (ha 2= 84.0%), flower hue angle (ha 2 = 95.0%), luminosity (ha 2 = 80.0%), chroma (ha 2 = 90.0%), hue angle (ha 2 = 99.9%) of the stem, 1,8-cineole contents (ha 2 = 88.0%), linalool (ha 2 = 96.0%), methyl chavicol (ha 2 = 97.0%), eugenol (ha 2 = 71.0%), Emethyl cinnamate (ha 2= 73.0%), β- elemene (ha 2 = 98.0%), methyl eugenol (ha 2 = 99.0%), E-α-bergamotene (ha 2 = 88.0%), and δ- cadinene (ha 2 = 97.0%). The combination of high ha 2 and high genetic gain (GGM) suggests that traits such as dry mass, plant height, canopy diameter, flower hue angle, luminosity, chroma, and hue angle of the stem, 1,8-cineole, linalool, methyl chavicol, eugenol, E-methyl cinnamate, β-elemene, methyl eugenol, E-α-bergamotene, δ-cadinene, and epi-α-cadinol are controlled by additive genetic action, making phenotypic selection effective for genetic improvement in this population. In Chapter 3, genetic parameters were estimated in a segregating population derived from a triple hybrid of basil (Mrs. Burns x Cinnamon) x Italian Large Leaf. Significant genetic variability was observed, confirmed by high CVg and CVf. High ha 2 was observed for dry mass (ha 2 = 89.0%), height (ha 2 = 73.0%), leaf chroma (ha 2 = 83.0%), luminosity (ha 2 = 91.0%), chroma (ha 2 = 86.0%), flower hue angle (ha 2 = 99.0%), stem luminosity (ha 2 = 95.0%), chroma (ha 2 = 93.0%), and hue angle (ha 2 = 99.9%), as well as for linalool (ha 2 = 95.0%), methyl chavicol (ha 2 = 83.0%), neral (ha 2 = 90.0%), geranial (ha 2 = 87.0%), Z-methyl cinnamate (ha 2= 96.0%), eugenol (ha 2 = 85.0%), E-methyl cinnamate (ha 2 = 94.0%), E-α bergamotene (ha 2 = 97.0%), and epi-α-cadinol (ha 2 = 99.0%). Together, the results underscore the importance of adequate nutrition and genetic study for the cultivation and improvement of basil.