Biometria comparativa das cultivares de mamoeiro THB e Aliança

Abstract

Papaya (Carica papaya L.) belongs to the Caricaceae family, it is a large and perennial herbaceous plant. It is the species in the family that has the greatest economic importance. The papaya cultivation cycle is around 18 to 24 months. Currently in Brazil there are 58 papaya cultivars registered with the Ministry of Agriculture, Livestock and Supply. Cultivars Aliança and THB are both registered, are part of the “Solo” group and it is in this group that most cultivars belong. The experiments were carried out at Fazenda Santa Terezinha of the company CalimanAgrícola SA, located in the municipality of Linhares, North of the State of Espírito Santo, Brazil, with latitude 19º 11' 49" S, longitude 40º 04' 20" W and altitude of 33 m . The climate of the region is of the tropical type Aw according to the Köppen classification. In the first chapter, the objective was to adjust an equation to estimate the fruit mass for the papaya cultivars Aliança and THB, using only one measure, length or width. For the modeling of the equations, 350 and 550 fruits of the 'Alliance' and the 'THB' were used, respectively, and another 50 fruits of each cultivar were used to validate the equations. The characteristics evaluated were the greatest width, the greatest length of the fruit and the observed mass. The equations that best fit were those of the power model that use width as an independent variable. In the second chapter, the objective was to determine the optimal plot size for the evaluation of experiments of the papaya cultivars Aliança and THB in the field from planting to the second year of cultivation using the Modified Maximum Curvature Method. Seven evaluations were carried out, always being examined 100 plants, these took place from August 2018 to November 2019. The characteristics evaluated in each plant in these evaluations were: stem diameter, number of fully formed and photositetically active leaves (green), leaf area total and height of the plant. It was also evaluated the height of insertion of the first fruit, production per plant in the first and second year. The optimal plot size for the cultivar Aliança and THB is five plants. The objective of the third chapter was to adjust the logistic model that describes the growth of biometric characteristics, such as plant height, stem diameter and total leaf area, of the papaya cultivars Aliança and THB in the field. Seven evaluations were carried out, from August 2018 to November 2019. 100 plants of each cultivar were evaluated in all evaluations. The characteristics evaluated in each plant were: plant height, stem diameter and total leaf area. The height of insertion of the first fruit, production per plant in the first and production per plant in the second year were also evaluated. The logistic model fitted well for the three growth characteristics of both cultivars, clearly showing the difference between the cultivars. A curve was fitted for each trait and cultivar. Cultivar Aliança took more days to reach the inflection point. The production per first-year plant in both cultivars was equal. The height of insertion of the first fruit and production per plant the second year were higher in the Aliança cultivar.