Resumo em Inglês:

Abstract: Caçari is a fruit tree that is native to the Amazon region of Brazil. The fruit is considered to have the highest vitamin C content of any edible fruit (13.757 mg 100 g-1 dry weight). The objective of this study was to evaluate the effects of 2,4-D and 6-BAP alone or in combination on in vitro callus induction and pro-embryogenic mass formation in caçari stem segments in different culture media as a precursor for caçari micropropagation. The experiment consisted of two culture media (MS and WPM) and combinations of four concentrations of 2,4-D (0, 1, 2 and 4 mg L-1) and BAP (0, 0.25, 0.5 and 1 mg L-1). The results showed that the highest percentage of callus formation (99%) was obtained in WPM supplemented with 4 mg L-1, 2,4-D and 1 mg L-1 BAP, and this combination resulted in 93% pro-embryogenic mass formation.

Resumo em Inglês:

Abstract The objectives of this study were to estimate genetic parameters and identify traits that contribute to early yield in Manihot esculenta Crantz. Ten traits were evaluated in two experiments, one with 138 genotypes and the other with 133, using a completely randomized block design with four replications. All genotype effects were significant. The accuracy was high for the traits, except leaf retention (0.57), and reliability ranged from 0.33 to 0.75. Root weight (RW) and number of roots (NR) showed the highest selection effectiveness (CV r ), although the estimate was less than 1. Moreover, RW and NR obtained high genetic correlation (0.70). Path analysis showed that only number of roots had a significant direct effect on root weight (0.49), and no indirect effect was found. Therefore, accessions exhibited sufficient genetic variability, and indirect selection based on early evaluation of number of roots can be applied in cassava breeding for fresh root yield, increasing gain over time.

Resumo em Inglês:

Abstract There is little information on pollen morphological analysis of papaya cultivars with different flesh color and origins. We observed pollen morphological characters of 17 papaya cultivars through scanning electron microscopy. The results showed that papaya pollen grains were monads, tricolporate, and small and medium-sized. The pollen grains were oblate-spheroidal to spheroidal. Foveolate, reticulate, and fossulate exine ornamentation were observed. Colpi width had maximum coefficient of variation of 25%; Shannon diversity index of all qualitative characters reached over 0.8. Using cluster analysis, 17 papaya cultivars were divided into three groups; there was no relationship between flesh colors and origins. The study findings suggest that pollen morphological analysis is valuable to provide references for breeding and genetic improvement of papaya.

Resumo em Inglês:

Abstract Peanut (Arachis hypogaea L.) is an important oilseed crop and food legume that is highly susceptible to biotic and abiotic factors. Wild Arachis species represent useful genetic resources because of their resistance to pests and diseases. In particular, understanding the affinity between B-genome species is important for broadening the genetic base of A. hypogaea (AABB genome), since only one population of A. ipaënsis is known, and relatively few other species have been described. Therefore, we aimed to determine the genomic affinity between A. ipaënsis and A. williamsii by developing hybrids. Microsatellite markers verified the hybrid status, and chromosome pairing and pollen viability results revealed that the species share high genomic affinity. Additionally, the presence of dyads detected in sporad and pollen analyses indicated the production of 2n gametes. These results will be useful for performing evolutionary studies and developing strategies for introgression programs to improve the B genome of A. hypogaea.

Resumo em Inglês:

Abstract The new table grape cultivar BRS Tainá produces white firm seedless grapes, agreeable flavor, balanced sugar-acid ratio, good berry adherence to the pedicel and yield of 50 ton ha-1 year-1. It is recommended for the tropical conditions of the Submédio do Vale do São Francisco. Propagative material is acquired from nurseries licensed by Embrapa.