Keize Pereira Junqueira

Variabilidade genética de acessos silvestres e comerciais de Passiflora edulis Sims. com base em marcadores RAPD

There are a great diversity of colors, sizes and aromas of fruits in wild accessions of P. edulis in Brazilian Savannah. These accessions are also important resistance sources against illness which can be incorpored in passionfruit breeding programs. In this work, the objetive was to evaluate the genetic variability in wild and commercial P. edulis accessions using RAPD markers. The genomic DNA of each accession was extracted and amplified using thirteen decamer primers (OPD-04, OPD-07, OPD-08, OPD-16, OPE-18, OPE-20, OPF-01, OPF-14, OPG-05, OPG-08, OPH-04, OPH-12 and OPH-16) to obtain RAPD markers. These markers were transformed in binary matrix data to estimate genetic distances among accessions and to perform cluster and graphical dispersion analysis. A total of 187 markers were generated, and only 28 (14.97%) of them were monomorphic. The genetic distances among the 15 P. edulis accessions varied from 0.091 to 0.496. The molecular markers demonstrated the high genetic variability of the wild and commercial P. edulis accessions. The accessions with yellow fruits presented greater genetic distances in relation to the accessions with purple fruits. Lower genetic distances were verified among the accesses of the same geographical origin.

Variabilidade genética de acessos obtidos de populações cultivadas e silvestres de maracujazeiro-doce com base em marcadores rapd

Sweet passion fruit (Passiflora alata Curtis) is gaining importance in the in natura fruit market due to differential value. Genetic breeding is crucial to improve crop quality and productivity. Molecular markers of DNA have been very useful by allowing obtaining a virtually unlimited number of genetic polymorphism without environment influence. This works objective was to study the genetic variability of 17 sweet passion fruit accesses, using RAPD molecular markers. One access of P. quadrangularis and another of P. edulis were used as outgroups. Genomic DNA samples of each one of them were extracted and 11 decamers primers (OPD 04, 07, 08 e16; OPE 18 and 20; OPF 01 and 14; OPG 08; OPH 12 and 16) were used to obtain the markers. The markers have been converted into a matrix of binary data, used as base to estimate genetic distances between accesses and to perform grouping and graphic dispersion analysis. From the total amount of markers, considering only P. alata accesses, it was observed 87 (62.12%) polymorphic bands, showing great intraspecific variability. Grouping analysis based on genetic distances allowed to subdivide 17 P. alata accesses in, at least, five groups of genetic similarity. The wild accesses contributed the most to the genetic basis expansion of the studied materials, opening good prospects for their use in breeding programs.

Enraizamento de estacas de três espécies silvestres de Passiflora

Em ambiente com nebulizacao controlada, estacas herbaceas com um par de folhas, contendo 2 ou 3 nos, foram testadas quanto ao enraizamento, utilizando-se de bandeja de poliestireno com celula de 95cm3 e saco plastico de 15x25x0,02cm com 1.730 cm3. Foram testadas estacas de Passiflora actinia, P. serrato-digitata e P. setacea. Observou-se que P. serrato-digitata apresentou 94,3% de estacas enraizadas com brotos e 2,4% de mortalidade; enquanto P. actinia e P. setacea apresentaram, respetivamente, 30,5% e 28,6% de estacas enraizadas com brotos e 56,8% e 60,7% de mortalidade. A alta mortalidade das estacas foi atribuida ao estado fenologico das matrizes de P. actinia e P. setacea e ao ataque de larvas de bradisia (Bradysia spp.) Estacas com dois e tres nos nao apresentaram diferencas significativas, e o recipiente saco plastico de 1.730 cm3 proporcionou melhor desenvolvimento das mudas.

Sacarose e pH na germinação in vitro de grãos de pólen de citros

Objetivou-se avaliar o efeito da sacarose e pH na germinacao in vitro de graos de polen das cultivares Valencia, Natal e Pera. Para testar o efeito da sacarose, os graos de polen foram distribuidos uniformemente em placas de Petri contendo meio de cultura basico constituido de 10 gL-1 de agar, 800 mgL-1 de nitrato de calcio e 200 mgL-1 de acido borico, acrescido de sacarose (0, 50, 100, 150 e 200 gL-1). Para verificacao do pH satisfatorio, os graos de polen foram inoculados em meio de cultura contendo 10 gL-1 de agar e 800 mgL-1 de nitrato de calcio, 200 mgL-1 de acido borico,100 gL-1 de sacarose e pH de 3,5; 4,0; 4,5; 5,0; 5,5; 6,0; 6,5. Apos inoculacao, os graos de polen foram incubados em BOD a 25oC por 12 horas. A porcentagem de germinacao foi obtida com auxilio de microscopio optico com objetiva de 10 X. Para todas as cultivares estudadas, a maior porcentagem de germinacao foi obtida com 100 gL-1 de sacarose e o maior numero de graos de polen germinados foi verificado em pH 6,5, sendo observado que maiores valores de pH aumentaram tambem a quantidade de polens estourados para as cultivares Natal e Pera e diminuiram para Valencia.

Receptiveness of the stigma and in vitro germination of orange pollen, submitted to different temperatures

The study was carried out in order to evaluate the effect of temperature and in vitor stigma receptivity on regeneration of orange cultivar (Valencia, Pera and Natal) pollen. Two experiments were carried out, in the first the ideal temperature of germination was assessed. Pollen was obtained from flowers at the balloon stage and inoculated in culture medium with 10 g L-1 agar, 200 mg L-1 boric acid, 100 g L-1 sucrose, 800 mg L-1 calcium nitrate, pH adjusted to 6,5 and incubated in a BOD chamber at temperatures of 23, 24, 25, 26 and 27oC during a 24-hour photoperiod. After 12 hours of incubation, the best temperature for pollen grain germination was 25oC for all varieties. In a second experiment, in order to test the receptivity of the stigma, flowers were collected at different flowering stages: small bud, balloon and open flower. The stigmas were by immersion exposed to hydrogen peroxide (perioxidase reaction), 3% for 3 minutes. Through the technique of Zeisler (1938), better results were detected at the balloon stage with 80 to 100% receptivity, while for the open flower the receptivity presented maximum indexes.