Cyro Paulino da Costa

Cucumber Beetle Resistance and Mite Susceptibility Controlled by the Bitter Gene in Cucumis sativus L

Antibiotic and nonpreference mechanisms are related in cucumber through the action of the bi gene and the absence of cucurbitacins. Cucurbitacins attract cucumber beetles and cause feeding whereas they have an antibiotic effect on two-spotted mites.

'PiraRoxa': cultivar de alface crespa de cor vermelha intensa

PiraRoxa is a triple red leaf lettuce (Lactuca sativa L.) cultivar resistant to Bremia lactucae, Thielaviopsis basicola and LMV, pathotype II. This cv. was obtained through pedigree selection from the cross between a Lolla Rossa RS 521998 and cv. Gizela. This shiny and intense red lettuce presents vigorous plants with loose leaves. In summer trials (2003/2004) PiraRoxa presented slow bolting performance (10 to 20 days later) in comparison to cvs. Banchu New Red Fire and Loretta. This is the first tropicalized red leaf lettuce with multiple disease resistance developed in Brazil.

Produção de bulbinhos de cebola em bandejas de isopor

Com o objetivo de estudar a viabilidade de producao de bulbinhos de cebola sob ambiente protegido em diferentes tipos de bandejas de poliestireno expandido foram instalados dois experimentos. No primeiro, trabalhando com a cultivar Serrana, foram avaliadas tres tipos de bandejas com diferentes numeros de plantas por celula: uma planta/celula na bandeja de 288 celulas, tres a cinco plantas/celula na de 128 e cinco a nove plantas/celula na de 72 celulas. No outro experimento, testaram-se nove cultivares, semeadas somente em bandejas de 128 celulas com tres plantas por celula. Utilizou-se o delineamento em blocos ao acaso com quatro repeticoes no primeiro ensaio e cinco no segundo, sendo cada parcela constituida por uma bandeja. Observou-se que quanto maior a densidade de plantio menor o tamanho do bulbinho (diâmetro e peso). O manejo adequado de adubacoes em cobertura pode viabilizar, tecnicamente, a producao de cinco bulbinhos com 1,3 cm de diâmetro (2 g) por celula, na bandeja de 128 celulas. Quanto ao ensaio de cultivares, x91Crioulax92 da Agroflora, x91Crioulax92 da Granja Lotario e x91Houstonx92 apresentaram 83%, 67% e 81% de plantas bulbificadas, enquanto que nas demais (x91Aurorax92, x91Baia Periformex92, x91Brownsvillex92, x91Petrolinex92, x91Pira Ourox92, x91Piranax92 e x91Serranax92) obteve-se 100% de bulbificacao. As principais vantagens na producao de bulbinhos em bandeja foram: uniformidade, ausencia de plantas daninhas e de patogenos. E um sistema que pode ser util aos viveiristas que tem entressafra de mudas nos meses de agosto a novembro, periodo de producao dos bulbinhos. Podera, tambem, ser uma alternativa na producao de bulbinhos para conserva, no controle de qualidade de lotes de sementes e em programas de melhoramento de cebola.

Phosphite effect on hot and sweet pepper reaction to Phytophthora capsici

Phosphite has been recommended to enhance plant resistance against Phytophthora. This work evaluated the response of hot and sweet pepper (Capsicum annuum L.) to Phytophthora capsici from juvenile up to the adult stage following treatment with phosphite. Sweet pepper hybrids considered to be resistant to P. capsici, like Reinger, Nathalie and Athenas, were evaluated. The susceptible checks were hybrid Magali R and cvs. Myr 10 and Ikeda. Hot pepper Criollo de Morelos 328, CM 334, BGH 3756, BGH 5122, CNPH 294 and Locorte were used as referential resistant lines. Phosphite did not have an effect on the hot pepper resistant lines because of their genetic homozygozity, while no protection was observed for the Athenas hybrid claimed to be resistant. Heterozygous hybrids recognized as resistant, like Reinger and Nathalie, showed higher survival following phosphite treatment, and their reaction was equivalent to the resistant cvs. CM 328 and CM 334, except for the fruiting stage. Depending of the hybrid heterozygous genotype, phosphite possibly acts through indirect phytoalexin induction through the inhibited pathogen.

Reação de pimentão ao potato virus y (PVYm)

Traditional sweet pepper cultivars showing susceptibility to the Potato virus Y (PVY) are being replaced by resistant hybrids with higher commercial value. Despite of much information about resistance source reaction and their inheritance, there is no knowledge about the genetic background of commercial resistant hybrids. Reaction of sweet pepper (Capsicum annuum L.) hybrids to the Potato virus Y (PVYm) such as Acuario, Magali R, Nathalie and their respective generations F2 and F3 as well as hybrids Amanda, Corteso W208, CPC-6272, Dagmar, Elisa, Magali, Margarita, Monteiro, Quantum, Vivo W205 was evaluated. Reaction to PVYm was evaluated as resistant or susceptible. Magali R and Nathalie hybrid did not show any mosaic symptoms. Magali R and Nathalie hybrids resistance is due to a single dominant gene indicating resistant versus susceptible parental lines crossing pedigree. Amanda, Acuario, Corteso W208, Dagmar, Elisa, Margarita, Monteiro, Quantum and Vivo W205, considered resistant to PVY, were highly susceptibility to PVY strain m. Hybrids, claimed as resistant to the Pepper mottle virus (PepMoV), were also resistant to PVYm.

'Gloriosa': cultivar de alface americana tropicalizada

Gloriosa is a tropicalized crisphead lettuce (Lactuca sativa L.) resistant to Thielaviopsis basicola. It was derived by selection from cv. Lucy Brown variants by pedigree method. Progenies S1 to S6 were selected for T. basicola resistance, desirable horticulture traits, slowbolting and adaptation for Brazilian summer crop. It presents a precocious cycle within 40 to 50 days of being planted, slowbolting, large head and three layers of frame levels. It is tolerant to Xanthomonas campestris pv. vitians and is able to be grown under high temperature and rainy summer in southern of Brazil. It is the first crisphead lettuce type developed for tropical regions of Brazil.

Hot pepper (Capsicum chinense, Jacq.) inheritance of reaction to powdery mildew

The pepper species C. chinense has been considered one of the most important resistance sources to powdery mildew Capsicum spp. However, the inheritance in this species was unknown. The purpose of this work was to study its reaction inheritance. Two powdery mildew resistant parents, Pimenta Cheiro 1 and PI 152225 and two moderately susceptible ones, Pimenta Doce IH-1761 and Pimenta Indio, were used to obtain three F1 and their respective F2 generations: Pimenta Doce IH-1761 ´ Pimenta Cheiro 1, Pimenta Indio ´ PI 152225 and Pimenta Doce IH-1761 ´ PI 152225. The powdery mildew epidemy was natural using inoculum from a highly-sporulating susceptible pepper host. Powdery mildew host reaction evaluations were carried out during the fruiting stage using a rating system based on disease severity scales varying from 1 (resistant) to 5 (highly susceptible). The experimental design was completely randomized. The following genetic parameters were estimated: gene action, heritability coefficient and expected selection gain in the F3 generation. The transgressive segregation in F2 indicated oligogenic inheritance. Results show the presence of additive, dominant, and epistatic gene action. The dominant and epistatic effects detected in crosses presented negative values, tending towards susceptibility. The heritability and selection gain estimates were moderate, with values of 35.5% and 1.7% for Pimenta Doce IH 1761 ´ Pimenta Cheiro 1, from 50.4% to 3.5% for Pimenta Indio ´ PI 152225, and 49% and 2.7% for the Pimenta Doce IH 1761 ´ PI 152225 crosses, respectively. These gene action results are favorable for breeding programs and exploration of hybrids.

Reação de acessos de pimentão e pimentas ao oídio (Oidiopsis taurica)

Powdery mildew caused by Oidiopsis taurica is one of the major diseases of Capsicum spp., causing damage due to defoliation of up to 75% and yield losses of up to 40%. Disease control with fungicide is inefficient, genetic resistance being the best way of control. Few resistant sources have been identified in Capsicum annuum. Capsicum spp. collection accesses of USP/ESALQ germplasm bank were screened in their reaction and identification of new resistance sources. The screening was carried out in a greenhouse under high inoculum pressure. Disease was assessed during fruit production using a severity scale varying from 1 (resistant) to 5 (highly susceptible). From 156 accesses evaluated 53 were resistant, represented by five accesses in C. annuum, 31 in C. baccatum and 17 in C. chinense. The hv-12 was the most resistant among the C. annuum accesses. Two new resistant sources were found in C. annuum, # 124 and chilli. These accesses showed different resistance mechanisms through hypersensitive host reaction. The commercial hybrids Reinger, Nathalie, Margarita, Magali R and Magda were susceptible or highly susceptible. Most of C. baccatum and C. chinense resistant accesses showed defoliation as a consequence of hypersensitive mechanism.

Inheritance of reaction to Leveillula taurica (Lev.) Arn. in Capsicum annuum L.

The use of fungicides to control powdery mildew in sweet pepper has been ineffective and genetic resistance is the best alternative. Resistance sources identified in Capsicum annuum L. are rare and unsatisfactory. The purpose of this work was to study the inheritance of C. annuum reaction to powdery mildew. Three homozygous powdery mildew resistant parents, HV-12, Chilli and #124 and three susceptible lines, 609, 442 and 428 were used to obtain seven F1s and respectively their generations F2: HV-12 x 609, 442 × HV-12, 428 × HV-12, Chilli × 609, #124 × 609, Chilli × HV-12 and #124 × HV-12. The powdery epidemic was natural using inoculum from highly sporulating susceptible pepper host. Powdery mildew host reaction evaluations were carried out during the fruit production using a rating system based on disease severity scales varying from 1 (resistant) to 5 (highly susceptible). The experimental design was completely randomized. The following genetic parameters were estimated: locus numbers, gene action, heritability coefficient, expected selection gain and observed progress in F3 generation, and possibly allelic relationship among resistance genes of different resistance sources. The HV-12×609 cross was the only one that showed absence of dominance. Other genetically analyzed crossings showed dominant and epistatic effects. Resistance was characterized as being due to at least four pairs of genes. The heritability and selection gains estimates were high. The resistance mechanisms of #124, Chilli and HV-12 showed differences in their expression.

Análise da capacidade combinatória em berinjela

ABSTRACT COMBINING ABILITY ANALYSIS IN EGGPLANT A total of five eggplant accessions 1: PI 206472, 2: ‘Long green’,3: ‘Campineira’, 4: ‘Florida Market’ and 5: ‘E-22’ - and the hybrids 1 x 3; 1 x 4; 2 x 4;2 x 5 and 3 x 5, were evaluated with regard to the average of length, diameter, and weight ofcommercial fruits, and average of number of fruits per plant and fruit yield. The average ofhybrids 1 x 2, 1 x 5, 2 x 3, 3 x 4, and 4 x 5 were predicted, based on partial diallel crossmethodology. The objective of this study was to identify both favorable accessions and hy-brids for breeding programs. The additive genetic effects were shown to be the most impor-tant for all traits analyzed. Accessions PI 206472 and ‘Campineira’ were indicated forintrapopulational breeding programs based on general combining ability. Among the ana-lyzed and predicted hybrids 1 x 3, 1 x 4, 1 x 5, and 3 x 5 presented potential for commercialexploitation. Index terms: Solanum melongena L.; eggplant; dialelic analysis; combining ability;heterosis.