Abstract Brazil accounts for a large percentage of the world’s citrus production, with ‘Tahiti’ acid lime tree standing out among several cultivated species. However, its cultivation is supported by a very narrow genetic base, being composed of few scion and rootstock options. In this way, the aim of this study was to evaluate the vegetative development and production of twelve ‘Tahiti’ acid lime clones on two rootstocks. The experiment was carried out at Fazenda José Guarete, municipality of São Mateus – ES. A randomized block design was used in the split plot scheme, with plot consisting of two rootstocks and subplot of the twelve ‘Tahiti’ acid lime clones. Traits evaluated were: vegetative development, production and productive efficiency, internal and external quality of fruits. Bello Fruit, Iconha, BRS Passos, Itarana, Persian 58, CNPMF 5059 and Elédio clones were superior in terms of production, vegetative traits and fruit quality. ‘Swingle’ citrumelo rootstock showed higher values for vegetative traits compared to ‘Riverside’ citrandarin. The clone and rootstock combinations that provided better agronomic performance in this study were BRS Passos, Bello Fruit, Elédio and Iconha grafted on ‘Swingle’ citrumelo and CNPMF 5059, Iconha and Elédio grafted on ‘Riverside’ citrandarin.

Combining longitudinal data and statistical models from perennial crops enabled us to estimate the optimum number of measures (harvests), implying accurate discrimination of superior genotypes in those crops. Herein, the goal of this study was to determine the optimum number of harvests based on yield traits and recommend a superior graft/rootstock combination (GRC) for Citrus latifolia Tanaka. Twenty-four GRCs of 'Tahiti' acid lime were evaluated from July 2017 to August 2018 for fruit yield per plant (FYP), number of fruits per plant (NFP), and longitudinal (LFD) and transversal fruit diameter (TFD). The experimental design was a randomized complete block with 4 replications. The experimental unit consisted of three individuals, totalling 244 individuals. The GRCs were composed of (i) two hybrids that were used as rootstock, citrumelo ‘Swingle’ (Citrus paradisi x Poncirus trifoliata) and cintrandarin ‘Riverside’ (Citrus sunki x Poncirus trifoliata); and (ii) 12 different C. latifolia genotypes that were used as grafts: Bello Fruit, Eledio, Iconha, Itarana, Santa Rosa, Bearss lime, CNPMF 01, CNPMF 02, CNPMF 2001, CNPMF 5059, BRS Passos, and Persian 58. Mixed models were employed to estimate the variance components. The optimum number of harvests was determined based on selective efficiency values above 0.9. The estimated repeatability coefficients presented values of 0.14 (LFD), 0.16 (TFD), 0.36 (FYP), and 0.38 (NFD). Based on the results, four harvests were able to choose genotypes based on FYP and NFP, whereas LFD and TFD were considered inefficient traits for recommending superior GRCs.

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The objective of this study was to determine a suitable plot size for field experiments with papaya genotypes. Two experiments were carried out using a randomized complete block design with 11 and 12 papaya genotypes, respectively. In both experiments, plots consisted of one row, with 10 plants each. Spacing between rows was 3.5 m, with 1.5 m between plants. The characteristic evaluated was fruit production in t ha -1 in first year of cultivation, and the basic unit used was one plant. Suitable plot size was estimated using Lin and Binns, and Hatheway's methods. These methods are complementary and should be used together in the determination of the optimum plot size. The results of these tests showed that the optimum plot size for the evaluation of yield in papaya was four plants by plot with four replications each assuming 30% of the precision for establishing differences among the means of two genotypes.

Genetic diversity studies provide fundamental information for characterization, conservation and utilization of available genetic resources in plant genetic improvement programs. To evaluate the genetic divergence among papaya accessions, 17 morphoagronomic variables from 59 accessions of the active germplasm bank were evaluated in an experiment at Santa Teresinha Farm, belonging to Caliman Agrícola S/A, in Linhares-ES, Brazil. The experiment was conducted in a randomized block design with two replicates. The divergence between the accessions was estimated using the Tocher optimization method and the agglomerative hierarchical approach based on the Unweighted Pair-Group Method Using an Arithmetic Average. (UPGMA). There was significant difference for all the variables evaluated, showing variability among the accessions. The variables plant height, first fruit insertion height, greatest thickness of fruit pulp, fruit diameter, and fruit length had heritability above 80%, indicating expressive gains in the simple process of selection. Genetic variability was found among the accessions, and Americano, short-peduncle-STZ-03 and Califlora 209 were the most divergent. The optimization methods Tocher and hierarchical based on UPGMA were partially concordant for the formation of heterotic groups of papaya accessions. The variables fruit mass, fruit diameter and plant height contributed the most to the genetic diversity.