Manoel Abilio de Queiróz

Correlações genotípicas, fenotípicas e de ambiente entre dez caracteres de melancia e suas implicações para o melhoramento genético

Genotypic, phenotypic and environmental correlations were estimated among the following traits of watermelon: number of days to the appearance of the first female flower (FF); number of fruits per plant (NF); weight of fruit (PF); flesh color (CP) and thickness (EP); longitudinal (DL) and transversal (DT) fruit diameter; sugar content (TS); number of seeds (NS) and weight of 100 seeds (PS) per fruit. The watermelon populations B9, Charleston Gray, Crimson Sweet, New H. Midget, M7, P14 and B13, their 21 F1 hybrids in diallel crosses and corresponding reciprocals were evaluated in the field, through a randomized complete block design with four replications. A great similarity among the estimates of genotypic and phenotypic correlation was found. Interesting genotypic correlations were observed between NF and PF, DL and DT; between PF and DL, DT, EP and TS and between CP and FF, EP and TS. Such correlations indicated that an increase in the number of fruits per plant is correlated with a reduction in the fruit weight and fruit size (function of DL and DT) and that an increase of fruit weight is associated with an increase in fruit size, thickness and sugar content. In addition, red flesh color was related with earliness and with increments of traits thickness and sugar content. The undesirable associations detected between number of fruits per plant and flesh color and number of fruits per plant and sugar content, however, was not sufficiently strong, indicating that it is possible to obtain recombinant individuals in segregating populations synthesized through crosses among contrasting populations.

Correlação entre testes de vigor em sementes de maxixe

RESUMO - O objetivo deste trabalho foi comparar a eficiŒncia de diferentes testes para determinaAao da qualidade fisiolUgica de sementes de maxixe (Cucumis anguria L.), visando melhorar sua utilizaAao como testes de qualidade e verificar suas relaAies com a emergŒncia de pl‚ntulas em campo. Foram avaliadas sementes de sete lotes, pelos testes de germinaAao, primeira contagem de germinaAao, condutividade elOtrica a 4 e 24 horas, envelhecimento acelerado, deterioraAao controlada, teste de frio sem solo e emergŒncia de pl‚ntulas em campo. O trabalho foi desenvolvido no LaboratUrio de AnAElise de Sementes e em um campo experimental da Embrapa-CPATSA, em Petrolina, PE, no perIodo de janeiro a maio de 1996. Nos testes de laboratUrio, o delineamento experimental foi inteiramente casualizado, e nos testes de campo foi usado o delineamento em blocos casualizados - ambos com quatro repetiAies de cinqenta sementes, sendo as mOdias comparadas pelo teste de Tukey a 1% de probabilidade. Os testes de germinaAao e vigor foram eficientes para detectar diferenAas de qualidade fisiolUgica entre lotes de sementes de maxixe. Os testes de deterioraAao controlada e de frio sem solo foram mais consistentes na separaAao dos lotes em diferentes nIveis de vigor, e ao mesmo tempo apresentaram os maiores nIveis de correlaAao com a emergŒncia de pl‚ntulas em campo. Termos para indexaAao: Cucumis anguria, qualidade fisiolUgica de sementes. CORRELATION AMONG VIGOR TESTS ON GHERKIN SEEDS ABSTRACT - This work was carried out with the objective of comparing the efficiency of different tests in the physiological quality of gherkin seeds (Cucumis anguria L.), looking for information for a better utilization of these quality control tests, as well as verifying their relation at field emergency. Seven lots of gherkin seeds were evaluated by the germination test, first count, electrical conductivity at 4 and 24 hours, accelerated aging, controlled damage, cold without soil, and field emergency. The trials were carried out at the Seed Lab and at an experimental field of Embrapa-CPATSA, at Petrolina, PE, Brazil, from January to May 1996. In the lab tests, a completely randomized design was used, and in the field tests, a randomized block design was used - both of them with four repetitions of fifty seeds, being the means compared by the Tukey test, at 1% of probability. The germination and vigor tests were effective to detect differences of physiological quality among gherkin seed lots. The damage control and cold without soil tests were more stable on the division of the lots by the vigor levels and, at the same time, showed the highest correlation with field emergency.

Caracterização morfológica e molecular de acessos de melancia

Accessions from the Watermelon Germplasm Bank collected in three different regions of the state of Bahia were characterized using morphological and molecular descriptors. The cultivar Crimson Sweet was added to the group as a check genotype. The field trial was carried out at the Experimental Station of Embrapa, Petrolina-PE. Uni- and multivariate analyses were performed. Samples of five to eight individuals from each of the 43 accessions were analyzed by RAPD technique, using six primers. Jaccard mean similarity coefficients among accessions and grouping by Tocher method were estimated. There were significant differences among accessions for all descriptors, except for the number of fruits per plant. Eight morphological descriptors (length of the main stem and fruit stripe pattern, soluble solid content, shape, weight, external color, and rind thickness at the flower scar and at the distal region) retained 79% of the variation observed among accessions. When the multivariate analysis was performed including cultivar Crimson Sweet, only two groups were formed: a group with solely the cultivar itself, and another with all the other accessions. When the cultivar Crimson Sweet was not included, the multivariate analysis showed nine groups of accessions, with a single group containing 69% of the accessions. Sixty-four RAPD markers were identified, out of which 31 were polymorphic. When accessions were grouped based on this molecular information, 28 groups were formed, 24 of them with a single accession. None of the groups with more than one accession contained individuals with the same geographical origin. RAPD markers revealed expressive polymorphism in several accessions, which is a good indication that such class of markers could be used in the characterization of accessions in watermelon germplasm banks.

Capacidade de combinação em sete populações de melancia

Este trabalho teve como objetivo estimar as capacidades geral (CGC) e especifica (CEC) de combinacao e os efeitos reciprocos (ER) em relacao a precocidade, componentes de producao e caracteristicas do fruto em sete populacoes de melancia. As populacoes foram intercruzadas em dialelo, incluindo os reciprocos. Todas as variaveis avaliadas, com excecao do numero de frutos por planta, apresentaram efeitos da CGC, CEC e ER significativos. Efeitos genicos aditivos foram importantes em relacao ao numero e peso de frutos por planta, assim como em relacao a cor, espessura e teor de solidos soluveis da polpa. Quanto ao numero de dias para o aparecimento da primeira flor feminina e numero de sementes por fruto, ocorreu predominância de efeitos genicos nao-aditivos. Foram identificadas algumas populacoes e algumas combinacoes hibridas superiores, que podem ser exploradas em programas de melhoramento. As populacoes tradicionais P14 e B9, coletadas no Nordeste do Brasil, sao promissoras para serem empregadas em programas que visem melhorar o numero e o peso dos frutos, ao passo que a M7 e promissora em relacao a precocidade. As variedades comerciais Charleston Gray e Crimson Sweet poderao ser empregadas para melhorar o teor de acucar e a cor da polpa.

Avaliação de caracteres morfológicos úteis na identificação de plantas poliplóides de melancia

The quantitative variation of the morphological characters in diploid, triploid and tetraploid genotypes of watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] was evaluated in three diploids, three tetraploids and three triploids hybrids, in relation to the number of chloroplasts per leaf stomata (NCF); width and length of the leaves (LFH e CFH); leaf width/length ratio (LF/CF); stem diameter (DCE); petal diameter in male and female flowers (DCM and DCF); ovary diameter (DOV); fruit weight (PMF); transversal and axial fruit diameter (DTF and DLF); fruit diameter axial/diameter transversal ratio (DL/DT) and rind thickness (EMC). A randomized block design was employed with three replications and five plants per plot. A nested analysis was performed and the ploidy level was considered the main factor. The genotypes were clustered at a dendrogram based on generalized Mahalanobis distance and also plotted on Cartesian plain using scores of the first and second canonic variables. Relative contribution of the variables to clustering was estimated by the Singh Method and the matrix of correlation was obtained using the Principal Component Analysis. The NCF presented higher relative importance (41%) to set divergence clusters, while DCF, DCM, DOV and DT/DL when analyzed together showed themselves efficient to discriminate diploids, triploids and tetraploid plants. So, they are recommended to aid watermelon breeding programs to obtain polyploid plants.

Fontes de resistência em melancia aos principais potyvírus isolados de cucurbitáceas no Nordeste brasileiro

The watermelon, Citrullus spp., can be infected by several virus species from the Potyviridae family. In the Universidade Federal do Ceara (Brazil), a research program was started to identify sources of resistance to Papaya ringspot virus type watermelon (PRSV-W), Watermelon mosaic virus-2 (WMV-2) and Zucchini yellow mosaic virus (ZYMV) utilizing accessions from the watermelon germplasm bank from Embrapa Semi-Arido in Petrolina. In the green house experiments, 4 plants of each accession were inoculated, separately, with PRSV-W, WMV-2 and ZYMV, 8 days after planting date. Four plants from each accession were maintained as control not inoculated. The symptoms appeared in 10 days, after inoculation, in the susceptible accessions. Fifteen days after the first inoculation, the plants without symptoms were re-inoculated. Twenty-five days after the first inoculation the accessions were evaluated through ELISA test, against the 3 virus antisera and the plants without symptoms gave negative results. Five accessions were resistant to three virus, 3 of them from Citrullus lanatus, one from C. lanatus var. citroides and other from C. colocynthis. Only one accession was resistant only to PRSV-W, 21 were resistant only to ZYMV and neither one presented resistance only to WMV-2. Nevertheless, 45 accessions showed resistance to ZYMV alone and in combination with other potyviruses. Some accessions can be crossed in order to obtain plants with triple resistance in segregating populations for plant and fruit characters, increasing the genetic variability of the sources of resistance to the main watermelon potyvirus.

Reação de acessos de Cucurbita sp. ao Zucchini yellow mosaic virus (ZYMV)

Cucurbita moschata is subject to infection by several viruses, especially from the family Potyviridae. The pumpkin accessions of the Vegetable Germplasm Bank Collection of the Universidade Federal de Vicosa and the Cucurbitaceae Germplasm Active Bank from the Embrapa SemiArido was evaluated to identify sources of resistance to the virus ZYMV. A total of 100 pumpkin accessions was evaluated, 61 from Embrapa Semi-Arido, 37 from UFV, and two from the seed company Sakata Seed Sudamerica. Four plants of each accession were inoculated with ZYMV during the cotyledonar phase before emergence of the first true leaves. Plants were re-inoculated two days later. Plants without symptoms after 30 days of the first inoculation were evaluated for the presence of ZYMV by indirect ELISA tests. After inoculation in January three accessions (BGH 1934, BGH-1937 and BGH-1943) were immune to ZYMV. Symptoms appeared in the susceptible accessions 10 to 15 days after the first inoculation whereas no symptoms were observed in the resistant and tolerant accessions until the end of the evaluation period and ELISA tests for virus concentration were negative. The accessions BGH-1934, BGH-1937, and BGH- 1943 can be used in breeding programs to incorporate resistance against ZYMV in commercial cultivars.

Diallel analysis of yield and quality traits of melon fruits

The purpose of this study was to estimate the general and specific combining ability of melon hybrids to identify the best combinations. Six parents and their respective hybrids were evaluated in a complete randomized block design with three replications. The following traits were assessed: total number of fruits, average fruit weight, yield, longitudinal diameter, transversal diameter, flesh thickness, internal cavity size, flesh firmness, and soluble solids. The traits total fruit number, yield, flesh firmness and soluble solids content are controlled by additive and non-additive effects, while average fruit weight, longitudinal diameter, flesh thickness, internal cavity size are controlled by additive effects. The most appropriate crosses for breeding of Cantaloupe, Honey dew, Piel del sapo, Meloa and Amarelo melon are, respectively: Gold Mine x Hy Mark, AF-646 x AF-1749, Meloa x Rochedo and AF-646 x Rochedo.

DIVERSIDADE GENÉTICA ENTRE ACESSOS DE COQUEIRO-GIGANTE

The tall coconut (Cocos nucifera L.) has great socioeconomic importance in Brazil and was first introduced on the coast of the north-eastern region, where it has been exploited in a semi-extractivist manner. The goal of this study was to quantify the genetic divergence between accessions introduced and preserved at the International Coconut Genebank for Latin America and the Caribbean, estimate the efficiency of descriptors used in the discrimination of the accessions, and indicate the essential descriptors for the activities of characterisation and evaluation. The accessions used were: Polynesia Tall; Tonga Tall; West African Tall; Rennel Tall; Rotuma Tall; Vanuatu Tall; Malayan Tall and Brazilian Tall Praia-do-Forte. Thirty-five quantitative descriptors recommended for the species were used. Genetic divergence was estimated by the Mahalanobis’s generalised distance and the cluster analysis was performed using the unweighted pair group method with arithmetic mean (UPGMA). The relative importance of the descriptors was measured according to Singh and Jolliffe’s methods, and the variables were selected taking into consideration the matching information in the two methods, eliminating those that were discarded in the two procedures. The agronomic characteristics indicated that the first canonical variable explained 90.25% of total variance. The most efficient descriptors for detecting the genetic divergence were: fruit equatorial circumference; nut polar and equatorial circumference; quantity of liquid endosperm; total fruit weight; nut weight; stem height; girth of stem at 1,5m height; number of leaflets; and number of bunches. The most dissimilar accessions according to the agronomic characteristics were Rotuma Tall and West African Tall, which can be primarily indicated as genitors for the formation of segregating populations in breeding programmes.

CLASSIFICAÇÃO BOTÂNICA E DIVERGÊNCIA GENÉTICA EM MELÕES DA AGRICULTURA FAMILIAR MARANHESE

The aim of this work was to perform botanical identification and to estimate genetic diversity in two sequential inbred generations (progenies S1 and S2) of melon accessions from traditional agriculture in the state of Maranhão, in order to generate useful information for commercial melon breeding. Two field experiments were carried out in a completely randomized block, using four replicates of 15 accessions from a first selfing cycle in 2013, and three replicates of 25 subaccessions (generation S2) in 2014. Flower and fruit descriptors were measured to obtain quantitative and qualitative data, in addition to a systematized photographic documentation of fruit for visually comparing the progenies S1 and S2. Distance matrices for quantitative and qualitative data were obtained and used to perform a joint analysis and UPGMA method. Large genetic diversity was found in the accessions analysed, since the presence of melon progenies was observed in the Cucumis melo ssp. agrestis, with its botanical varieties momordica and conomom, and of the Cucumis melo ssp. melo, with the botanical varieties cantalupensis and chandalak. Divergence analysis showed the formation of three groups in generation S1 and four groups in S2. However, the groups were not separated either by subspecies or by botanical variety. Thus, in addition to the large genetic diversity among and within melon accessions from family farming in the state of Maranhão, the progenies presented a large introgression of traits of the different subspecies and their botanical varieties due to the reproductive system and seed management of these species.